# Adaptive Cruise Control (ACC): connector corrosion...



## perfrej (Dec 24, 2009)

My adaptive cruise control and front assist systems started to fail a few days ago. Cruise would let go with a "bong" and "ACC Fail" message. I would stop the engine at the next down hill and the system would restart and function again. Yesterday the restart option sort of disappeared and the failure went into permanent mode. So, time to drive by the tech and see what was cooking.

The Phaeton is a marvel of interconnected systems and had error codes in the engine, the transmission, the distance control unit, the cruise control and one or two more. Being a truly demonic Phaeton tech, Jan immediately remembered a technical bulletin on the subject with corrosion in one of the two conectors to the TRW control unit. The note specified that the harness between the right and left sides of the area just below the wipers to be exchanged for a new version with a different brand connector that is better sealed for moisture.

There is now a request for a free exchange of the harness in the system, and in the mean time the connector in question has been cleaned with VW contact cleaner. It works, sort of...

I guess you North Americans don't have the problem 

I'll get the number of the bulletin and publish it in case someone this side of the pond gets the problem.

/per


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## Voodtje (Oct 23, 2009)

Interesting topic, as I too have problems with the adr. it gives the faultcode 01674, aicc trip switch non-funtion. could you tell me more about locations of the specific parts?

Jean-Pierre


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## lucatambu (Apr 5, 2011)

yes, please, to have date/number of the technical bulletin can be very helpful for us european ...
thank you i advance
:thumbup:


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## WillemBal (Nov 20, 2010)

Voodtje said:


> Interesting topic, as I too have problems with the adr. it gives the faultcode 01674, aicc trip switch non-funtion. could you tell me more about locations of the specific parts?


Hi Jean Pierre,
The fault code 01674 is generated by a supposedly malfunctioning release switch inside the Brake Booster itself. The Brake Booster (F317) itself isn't hard to find. Just open the hood and look at the LHS of the plenum chamber. You can see a little white tank, the reservoir for the brake oil fluid, which is connected to the brake booster.
But the location of that release switch is more complex. It is there to help distinguish whether the brake was electrically activated. You might say that this is a vital component to determine whether the brakes are actually working when the Brake Booster Controller J539 (Address 23) gives a signal to the solenoid inside the brake booster.
Perhaps you have noticed, with the ACC (Adaptive Cruise Control) set to a specific speed, that the brake pedal moves when the car too closely approaches a car in front of you, obviously due to a difference in speed between yours and the one in front of you. When the Phaeton approaches a car, you will first be notified by the instrument cluster in the form of bars indicating the real distance to the car and the set minimum distance to that car. The ADR (Automatic Distance Regulation, Address 13) then will come into action in order to maintain the pre-set distance. It will first release the gas throttle so that your car will smoothly adapt to the speed of the car in front of you. If that does not help, the Brake Booster Controller starts to work and will activate the Brake Booster by activating a solenoid, indirectly causing brake pressure. The release switch sits there to monitor this happening. When it does not switch its contact, there will be an upcoming safety issue, reason for disabling the ACC all together.

For this ACC system to work properly, no errors are allowed of any of the related components. It needs literally flawless ABS controller, Brake Booster, TPMS system, Tranmission Control, Steering Wheel Electronics, CAN controller and zero troubles with your engine (the ECU). If any of these controllers (possibly others) the ADR/ACC function will not be available, which will be indicated in the instrument cluster.

To solve this problem, a diagnostic scan tool such as VCDS is essential. A complete scan has to be made, then any controller which has been throwing on or more DTC's must be reset. When the fault is not sporadic (=persistent), it will automatically generate the same DTC again. This implies that you can either solve the problem or diagnose where the problem is by means of the VCDS. Let's hope that it is not caused by the release switch itself, as this switch may be very hard to reach, being built inside the brake booster.

Willem


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## Zaphh (Jul 5, 2008)

A slight note: ADR works even when TPMS is ineffective (the case in my car now).

P.


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## Bindaham (Apr 4, 2014)

My ACC doesn't function. Here's the scan faults that shows why:

*Address 13*: Auto Dist. Reg Labels: 3D0-907-567.lbl
Part No: 3D0 907 567 E
Component: AC101 V8 6HP194 10 0334 
Coding: 0001451
Shop #: WSC 00000 000 00000
VCID: 2E530240BAD4F851CD7-5140

*1 Fault Found:
00233 - Sensor for Automatic Distance Control Coverage Area Blocked 
003 - Mechanical Failure
*


*Address 17*: Instruments Labels: 3D0-920-xxx-17.lbl
Part No: 3D0 920 881 Q
Component: KOMBIINSTRUMENT RB4 0421 
Coding: 0005121
Shop #: WSC 79301 793 90315
VCID: 3467102854F8D281BB3-515E

*1 Fault Found:
00466 - Control Module for Steering Column Electronics (J527) 
004 - No Signal/Communication - Intermittent
*



*Address 23*: Brake Booster Labels: None
Part No: 3D0 907 563 B
Component: BREMSBOOSTER 4010 
Shop #: WSC 00000 000 00000
VCID: 275DF764952EA9190E1-5140

*1 Fault Found:
01674 - ADR Release Switch in Brake Booster 
009 - Open or Short to Ground - Intermittent - MIL ON* 



Regards,

Salah


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## Paximus (Aug 26, 2011)

Hi Salah,

On my car, a mechanical blockage in front of the radar sensor will self-clear once 'normal service' is resumed. While the obstruction is present (dried salt, water splash, ice) a message is put up on the in-dash display. Of course, painting over the radar window on the bumper cover fitted on pre-2007 cars will not self-clear!

There are three sensors on the Brake Booster when ADR is fitted. Just to complete our DTC Message Collection, on mine I have seen DTCs from the other two, which throw up a fault message on the ADR display and turn it off for a few ignition cycles.

I have not got round to replacing the sensors yet. I hope it's not a master cylinder seal, or corrosion on the Brake Booster Controller plugs, which can short out the signals from the three sensors referred to above (see TPI 2021809/4). If it is the latter, then I can't find the actual Brake Booster controller location on my RHD car, and VW Germany was unable to tell me through an ERWIN request. They said to follow the wires! There is not much access on a V10, a dormouse could not follow the wires, maybe an ant could.


Address 23: Brake Booster Labels: 3D0-907-563.lbl
Part No: 3D0 907 563 C
Component: BREMSBOOSTER 4310
Shop #: WSC 00000 000 00000
VCID: 285501749817EF5EF37-513C

2 Faults Found:
*01435 - Brake Pressure Sensor 1 (G201)
009 - Open or Short to Ground - MIL ON*

*01673 - Potentiometer for Diaphragm Position in Brake Booster
009 - Open or Short to Ground - MIL ON*


Incidentally, I see that your VCDS does not have Michael's Brake Booster label file 3D0--907-563.lbl. What version of VCDS do you have?

Regards,
Chris


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## Bindaham (Apr 4, 2014)

Hello Chris,

Unfortunately, I haven't got the time recently to go under or around the car but will definitely explore these issues soon. 

I have found  this site for you (SSP 272) that might be of help in determining the location of the Brake Booster controller (J539) location (please refer to page 52 in that site). 

With regard to the version of VCDS that I use, It's the last version prior to the last update. I noticed at my last scan that there was a new update.

Regards,

Salah


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## Paximus (Aug 26, 2011)

Hi Salah,

Thanks very much for looking up the SSP. Unfortunately the RHD (Right Hand Drive) car does not have the Brake Booster controller in that physical location, which is why I asked VW HQ. It is a shame that they do not know where it is! I have had a long search, but cannot find it. I may now ask the factory.

I hope you find the cause of your ADR problem. Maybe it is exactly what the car is reporting, the ADR release switch.

Chris


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## Bindaham (Apr 4, 2014)

That's strange Chris! I thought since you have a RHD vehicle, the controller should either be in the same position as in our LHDs or in the opposite position.

Will definitely report on that switch.

Regards,

Salah


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## Paximus (Aug 26, 2011)

*Location of Brake Booster Controller in RHD Phaeton*

To answer my own question, on a Right-Hand Drive Phaeton the Brake Booster Controller is fitted down beside the engine controllers on the left side of the vehicle in the plenum chamber. The 3D drawing from the factory (attached below) explains where it is. It is reasonably accessible from inside the engine bay, by which I mean the wheel arch liner does not have to be removed.

This controller operates under the request of the radar unit itself at the front of the vehicle, operating the brakes as needed and monitoring the integrity of its part of the ADR system. It also contains a relay which disconnects the drive train bus from the radar assembly when the car is secured, to prevent snooping on the bus and acquiring information capable of helping car theft. The radar assembly is physically outside the security perimeter, so is vulnerable.

Chris


*Location of Brake Booster Controller in RHD Phaeton*








image (c) volkswagen


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## Paximus (Aug 26, 2011)

Again, to close my own open question on my ADR fault: The original problem was that the radar cruise was shown as 'Defective' in the in-dash display, and the Brake Booster Controller recorded a DTC saying that the G201 Brake Pressure Sensor output was implausible.

After a while, a second DTC appeared saying that the 'Potentiometer for Diaphragm Position in Brake Booster' was intermittently giving zero output.

The whole problem started on collecting the car from a main dealer after a routine service with brake fluid replacement.


-------------------------------------------------------------------------------
Address 23: Brake Booster Labels: 3D0-907-563.lbl
Part No: 3D0 907 563 C
Component: BREMSBOOSTER 4310
Shop #: WSC 00000 000 00000
VCID: 285501749817EF5EF37-513C

2 Faults Found:

01435 - Brake Pressure Sensor 1 (G201)
008 - Implausible Signal - MIL ON​
01673 - Potentiometer for Diaphragm Position in Brake Booster
009 - Open or Short to Ground - Intermittent - MIL ON​-------------------------------------------------------------------------------


These were the actions taken over a two-year period:

The G201 Brake Pressure Sensor 8E0 907 597 was replaced. This is the one on the ABS unit. It made no difference.
The G420 Potentiometer for Diaphragm Position in Brake Booster was replaced. This made no difference either.
The J539 Brake Booster Controller (aka Control Unit for Distance Regulation) was checked for plug corrosion as per TPI 2021809/4. The plugs were dry and sound. The TPI implies a water splash risk to the controller on a Left-hand drive car (it's near the base of the windscreen and under a coolant tank which has been known to leak), but my Right-hand drive Phaeton has the Brake Booster Controller in a drier position near the engine controllers.
The cable loom from the J539 Brake Booster Controller to the Brake Servo Sensors and the G201 was tested, no fault found.
The J539 Brake Booster Controller 3D0 907 563B was swapped out for a used unit obtained from allegro.pl. This cleared the Potentiometer fault report.
The F318 ACC Trip Switch (pressure) was replaced. This cleared the fault and the ADR now works. The F318 is the 3D0 907 597 brake pressure sensor mounted on the brake master cylinder.

This has been a trying time. The G201 Brake Pressure Sensor is around £200, the G420 position sensor is around £100, the J539 Brake Booster/Adaptive Cruise Controller is around £500 and the F318 brake pressure sensor is around £200. The labour was around £600.

But I am now delighted to have my radar cruise back in operation! I do a lot of night driving on clear roads and it's the best thing ever. It is so good to not have to flip the eyes down to the speedo every 60 secs to avoid a ticket, since to the Phaeton 100mph feels not so much different from 70mph, and it is so easy to drift over 80 and get caught by an average speed trap. (So far, so good). But if there is traffic, the adaptive cruise acts like a safety monitor or co-pilot and reduces the adrenalin, making for a lower-stress drive.

Chris


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## bluebit (Oct 26, 2018)

Paximus said:


> was checked for plug corrosion as per TPI 2021809/4.


Hi Chris - but where i can find this TPI 2021809/4 ?
Maybe you can send me this document to ([email protected])?

Best Regards 
Bartosz bluebit


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## Paximus (Aug 26, 2011)

Hi Bartosz bluebit,

Here's that TPI 2021809/4 document describing the ACC fault that I referred to.

I hope that helps.

Chris


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## ElSmoko (Feb 10, 2019)

I bought my car in part because it had ACC, and it worked perfectly for a couple of months before exhibiting the same problems as the OP described. My error codes point to "electromagnetic interference" on the brake sensor, which makes me think the connection is corroded or potentially the sensor is on its way out. I've lifted the cowl and can see the back of the connector, but it lives behind some of the brake master cylinder hard lines. Does anyone have any advice on how best to get the connector off and cleaned for example?


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## Paximus (Aug 26, 2011)

Hi,

According to VW, on a LHD car you have to disconnect the brake pipes from the master cylinder to access the F318 "ACC trip switch" (it's really an analogue pressure sensor identical to the main G201 on the ABS distributor assembly). Unfortunately, there are no official instructions for doing this for a RHD car. Obviously, the secondary coolant tank, if there is one, has to be swung to one side to see the brake booster and master cylinder assemblies.

I replaced the G420 'Membrane Movement Sensor' on the Brake Booster itself on my RHD car without removing pipes, (it made no difference to my ACC fault, by the way) but I got the dealer to change that F318 pressure switch because a 2-year brake fluid change was due anyway. I suppose either of those could be faulty, assuming the ADC is tripping because the brake pressure map is not tracking the brake pedal/membrane movement map. The third ADC safety switch is buried inside the brake booster. I have no experience of that, except having read that it is not accessible and the whole booster has to be changed if it's faulty.

The F318 on the master cylinder was the cause of my ADC problem. After replacement the ADC was back in glorious business. I will have a quick look at the brake booster area on the RHD car to refresh my memory when I get a chance, as the repair was done a few years ago.

I now realise how good the Phaeton's relatively early implementation of radar ACC is, after comparing it with the 12-year newer design of BMW i3's disappointing video camera-based system. That gives up and drops out abruptly exactly when the poor human at the wheel (me) could do with some technological backup, ie when the sun is low in front of you, or there is a sudden strong sunlight reflection from a wet road, or at night when there are a set of relatively confusing lights spread out ahead. The Phaeton's ACC is not perfect but it's certainly good enough to give a very welcome safety net for braking and therefore a much more relaxing drive. It doesn't care about those i3-type problems and continues regardless. I would not be without it.

Chris


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## ElSmoko (Feb 10, 2019)

I believe mine is the sensor on the bottom of the booster, which I think realistically means the booster will have to come out. In which case I will more than likely replace the sensor just in case, and hope ACC comes back. It mainly seems to trip when it would "consider" braking, such as when passing a slower car, so I suspect it is a sensor reading mismatch. I have error codes for ADR release switch issues, and after a while they seem to build up and completely stop ADR/ACC working at all. I took it to VW and they said there were no codes other than the radar unit itself failing, a £2100 repair. Reading the codes myself the radar sensor shows no faults, just the ADR switch.


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## Paximus (Aug 26, 2011)

Hi,

Feel free to post the VCDS scan results if you have them.

The plug on the lower part of the brake booster is certainly the one that connects to the internal ACC safety switch gubbins, the one that can't be replaced. However, it might well be worth changing the ACC pressure sensor on the master cylinder first, it's a cheap part and would rule it out before you invest in a brake booster. Likewise the brake pedal/diaphragm travel sensor is not too expensive, compared to cost of a brake booster assembly.

Chris


*LHD 2008 Phaeton 3.0TDi ACC connections at the brake booster*
The three items marked B are the ACC Pressure Switch on the master cylinder on the left, the ACC trip switch inside 
the booster (centre) and the ACC diaphragm/brake pedal movement sensor clipped to the brake booster (right).








image (c) Volkswagen


*RHD version (this one is from the Bentley Flying Spur)*








image (c) Bentley Motors


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## ElSmoko (Feb 10, 2019)

Since you very kindly offered, here's the errors I've pulled out of the car this afternoon. These were the only faults logged, and I've cleared them all. It's got me a little stumped, as there are now more faults than there were previously. Every time I reset all the codes, and normally after a start or two I get front assist and ACC working again, but only for a few miles, maybe up to half an hour if I'm lucky. After a few days or so, it goes back to failing every time I start ACC.

If you have any ideas of what to try, I would be eternally grateful. My local VW dealer had no ideas, all the specialists I've called around here have said "go to VW", so I'm somewhat on my own! But I have the power of you guys 


Sunday,24,February,2019,15:03:42:00001
VCDS Version: Release 17.8.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 01: Engine Labels: None
Control Module Part Number: 3D0 907 401 D HW: 3D0 907 401 D
Component and/or Version: 3.0TDI EDC17A100AG 0050
Software Coding: 0406002C190F0260
Work Shop Code: WSC 01065 000 00000
VCID: 204ED81CF0C3E246AA-5120
2 Faults Found:

053283 - Please Check Fault Codes in Control Module for Automatic Distance Regulation 
U1023 - 003 - - Intermittent
Freeze Frame:
Fault Status: 00100011
Fault Priority: 6
Fault Frequency: 1
Reset counter: 255
Mileage: 119259 km
Time Indication: 0
Date: 2019.02.13
Time: 19:52:02

Freeze Frame:
RPM: 0 /min
Speed: 0.0 km/h
(no units): 0.00
(no units): 0.00
Bin. Bits: 00000100
Bin. Bits: 00000111
Bin. Bits: 00000001

049441 - No Communication with ABS Brake Control Module 
U0121 - 007 - - Intermittent
Freeze Frame:
Fault Status: 00100111
Fault Priority: 2
Fault Frequency: 13
Reset counter: 255
Mileage: 119259 km
Time Indication: 0
Date: 2019.02.13
Time: 20:02:53

Freeze Frame:
RPM: 0 /min
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 11.78 V
Bin. Bits: 00000000
(no units): 8.0


Readiness: 0 0 0 0 0 


Sunday,24,February,2019,15:04:31:00001
VCDS Version: Release 17.8.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 02: Auto Trans Labels: 09L-927-760.lbl
Control Module Part Number: 09L 927 760 N HW: GS1 9.1 1.4 
Component and/or Version: AG6 09L 3,0 TDI RdW 3401
Software Coding: 0000001
Work Shop Code: WSC 00000 000 00000
VCID: 428A72941E8FD056DC-515A
1 Fault Found:

049442 - No Communication with ESP (Vehicle Dynamics) Control Module 
U0122 - 000 - - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 119259 km
Time Indication: 0
Date: 2019.02.13
Time: 20:02:53


Sunday,24,February,2019,15:05:27:00001
VCDS Version: Release 17.8.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 05: Acc/Start Auth. Labels: 3D0-909-13x-05.lbl
Control Module Part Number: 3D0 909 139 B HW: 5WK 485 04
Component and/or Version: Kessy 6840
Software Coding: 0004328
Work Shop Code: WSC 01065 000 00000
Additional Info: XXXXXXXXXXX ELV XXXX 
Additional Info: Geraet 00000
VCID: 285EC03C9FF31A06E2-807C
1 Fault Found:

01316 - ABS Control Module 
004 - No Signal/Communication - Intermittent


Sunday,24,February,2019,15:06:02:00001
VCDS Version: Release 17.8.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 13: Auto Dist. Reg Labels: None
Control Module Part Number: 3D0 907 567 K HW: 3D0 907 567 K
Component and/or Version: AC201 RDW 1 031 0671
Software Coding: 0010000
Work Shop Code: WSC 01065 000 00000
VCID: 3466244C533B6EE65E-8060
1 Fault Found:

00272 - Function Disabled due to Electromagnetic Interference 
012 - Electrical Fault in Circuit - Intermittent - MIL ON
Freeze Frame:
Fault Status: 10101100
Fault Priority: 7
Fault Frequency: 2
Reset counter: 95
Mileage: 119264 km
Time Indication: 0
Date: 2019.02.14
Time: 09:55:53

Freeze Frame:
Count: 18


Sunday,24,February,2019,15:07:02:00001
VCDS Version: Release 17.8.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 19: CAN Gateway Labels: 6N0-909-901-7L.clb
Control Module Part Number: 6N0 909 901 HW: 3D0 920 982 P
Component and/or Version: J533 GW-K-CAN TP20 4227
Software Coding: DFFFF7BE031003
Work Shop Code: WSC 12345 067 57206
VCID: 70EEE85C63A312C67A-8024
3 Faults Found:

01044 - Control Module Incorrectly Coded 
000 - - 
Freeze Frame:
Fault Status: 01100000
Fault Priority: 2
Fault Frequency: 1
Reset counter: 53
Mileage: 119259 km
Time Indication: 0
Date: 2019.02.13
Time: 19:52:55

01342 - Engine Control Module 2 (Slave 1) 
004 - No Signal/Communication
Freeze Frame:
Fault Status: 01100100
Fault Priority: 2
Fault Frequency: 1
Reset counter: 53
Mileage: 119259 km
Time Indication: 0
Date: 2019.02.13
Time: 19:52:55

01316 - ABS Control Module 
004 - No Signal/Communication - Intermittent
Freeze Frame:
Fault Status: 00100100
Fault Priority: 2
Fault Frequency: 1
Reset counter: 93
Mileage: 119259 km
Time Indication: 0
Date: 2019.02.13
Time: 20:02:53


Sunday,24,February,2019,15:07:36:00001
VCDS Version: Release 17.8.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 23: Brake Booster Labels: None
Control Module Part Number: 3D0 907 563 E
Component and/or Version: BREMSBOOSTER 0220
Software Coding: 
Work Shop Code: WSC 00000 000 00000
VCID: 2A5A3A3481FF2816F4-807E
2 Faults Found:

01674 - ADR Release Switch in Brake Booster 
009 - Open or Short to Ground - MIL ON
Freeze Frame:
Voltage: 11.00 V
Torque: 0.0 Nm
Absolute Pres.: 0.0 bar
Content: 0.0 mm
Current: 0.000 A
Speed: 0.0 km/h
Count: 71

00272 - Function Disabled due to Electromagnetic Interference 
000 - - - Intermittent - MIL ON
Freeze Frame:
Voltage: 11.00 V
Torque: 0.0 Nm
Absolute Pres.: 0.0 bar
Content: 0.0 mm
Current: 0.000 A
Speed: 0.0 km/h
Count: 104


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## Paximus (Aug 26, 2011)

Hi,

Thanks for posting the scan. I sorted the fault codes, because I'm not as young as I once was and by the time I get to the end I've forgotten the beginning:











1. I assume you haven't pulled any controller connectors off recently? That logs a code or two which get picked up much later.
2. The CAN Gateway says it can't find Engine 2. This is odd because I didn't think 3.0TDi had an Engine 2 controller. Am I wrong?
3. The Brake Booster faults are all registered during engine cranking, as far as I can see. This might be useful information.


Please may I ask when you replaced the vehicle AGM batteries? Both were due for replacement in 2018. The reason I ask is that for 300 millisecs during cranking the left battery can only supply a reliable voltage for the first 5 years of its life. After that, it provides a low voltage during that critical fraction of a second, enough to affect some controller memory status, so the infamous gremlins start to appear. It would be nice to rule these out. This could confuse the CAN Gateway into not recognising controllers that _are _present (eg the ABS one here), and/or looking for ones that are _not _present (Engine 2 maybe?)

If there are CAN-bus disruptions, this could trigger some odd symptoms. Have you ruled out fraying of the steering column CAN-bus cable? This can short out at the base, next to the carpet. As per the drive-train SSP, this could cause some gremlins because both Drivetrain and Comfort CAN-buses run in the column.












Perhaps someone else can chip in.

Chris


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## ElSmoko (Feb 10, 2019)

Thanks for your time on this Chris, you're a legend. Worryingly, I didn't actually start the car when I read these codes off - I was sat in it quickly pulling the codes with the ignition on but the engine off. I hadn't noticed that the voltage dropped so low, that is scary. I just checked the date on it and shockingly it's week 26 2007! So I shall be getting myself to eurocarparts probably ASAP to swap that out, and see what happens. I'm not convinced it's the root of all my troubles, but I can certainly imagine it causing some. I drove the car again today and the ACC worked perfectly until I pulled up on the drive after a 10 minute journey, when the front assist and ACC failed. I'm convinced it's a sensor, but I'll keep my fingers crossed it's a battery!


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## ElSmoko (Feb 10, 2019)

OK so today I picked up a battery from EuroCarParts, not a pukka VW one but a 100AH Exide Premium one with 5 year warranty. I've had good luck with Exide before so I was happy to go with it, and it was a good price as well with the 50% discount they have on at the moment. It was a total pig to get in, but it's in! I only replaced the left side battery for now, partly to see if it would fit (which it does, perfectly), but I will replace the right side one as well now I know it fits.

My faults have changed a little, but the problems still persist for sure  I've done a couple of journeys and cleared the codes, but the ones below keep coming back. I did have ACC working perfectly for a few minutes again today, so I think I still have some sort of sensor problem. I really want to get this sorted so my ACC works properly and reliably (it's a cruise control kinda car!) so I'd love any advice on how to sort it out! 

Wednesday,27,February,2019,19:25:07:00001
VCDS Version: Release 17.8.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 01: Engine Labels: None
Control Module Part Number: 3D0 907 401 D HW: 3D0 907 401 D
Component and/or Version: 3.0TDI EDC17A100AG 0050
Software Coding: 0406002C190F0260
Work Shop Code: WSC 01065 000 00000
VCID: 204ED81CF0C3E246AA-513C
Fault Codes have been Erased

1 Fault Found:
053283 - Please Check Fault Codes in Control Module for Automatic Distance Regulation 
U1023 - 003 - 
Freeze Frame:
Fault Status: 01100011
Fault Priority: 6
Fault Frequency: 1
Reset counter: 255
Mileage: 119586 km
Time Indication: 0
Date: 2019.02.27
Time: 19:24:39

Freeze Frame:
RPM: 756 /min
Speed: 0.0 km/h
(no units): 0.00
(no units): 0.00
Bin. Bits: 00000100
Bin. Bits: 00000111
Bin. Bits: 00000001


Readiness: 0 0 0 0 1 

Wednesday,27,February,2019,19:26:01:00001
VCDS Version: Release 17.8.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 13: Auto Dist. Reg Labels: None
Control Module Part Number: 3D0 907 567 K HW: 3D0 907 567 K
Component and/or Version: AC201 RDW 1 031 0671
Software Coding: 0010000
Work Shop Code: WSC 01065 000 00000
VCID: 3466244C533B6EE65E-8060
1 Fault Found:

00272 - Function Disabled due to Electromagnetic Interference 
012 - Electrical Fault in Circuit - MIL ON
Freeze Frame:
Fault Status: 11101100
Fault Priority: 7
Fault Frequency: 1
Reset counter: 58
Mileage: 119582 km
Time Indication: 0
Date: 2019.02.27
Time: 19:16:16

Freeze Frame:
Count: 18


Wednesday,27,February,2019,19:26:45:00001
VCDS Version: Release 17.8.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 23: Brake Booster Labels: None
Control Module Part Number: 3D0 907 563 E
Component and/or Version: BREMSBOOSTER 0220
Software Coding: 
Work Shop Code: WSC 00000 000 00000
VCID: 2A5A3A3481FF2816F4-807E
1 Fault Found:

00272 - Function Disabled due to Electromagnetic Interference 
000 - - - MIL ON
Freeze Frame:
Voltage: 12.00 V
Torque: 0.0 Nm
Absolute Pres.: 0.0 bar
Content: 0.0 mm
Current: 0.000 A
Speed: 0.0 km/h
Count: 104


Wednesday,27,February,2019,19:27:23:00001
VCDS Version: Release 17.8.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 19: CAN Gateway Labels: 6N0-909-901-7L.clb
Control Module Part Number: 6N0 909 901 HW: 3D0 920 982 P
Component and/or Version: J533 GW-K-CAN TP20 4227
Software Coding: DFFFF7BE031003
Work Shop Code: WSC 12345 067 57206
VCID: 70EEE85C63A312C67A-8024
2 Faults Found:

01342 - Engine Control Module 2 (Slave 1) 
004 - No Signal/Communication
Freeze Frame:
Fault Status: 01100100
Fault Priority: 2
Fault Frequency: 1
Reset counter: 58
Mileage: 119576 km
Time Indication: 0
Date: 2019.02.27
Time: 13:45:01

01044 - Control Module Incorrectly Coded 
000 - - 
Freeze Frame:
Fault Status: 01100000
Fault Priority: 2
Fault Frequency: 1
Reset counter: 58
Mileage: 119576 km
Time Indication: 0
Date: 2019.02.27
Time: 13:45:02


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## ElSmoko (Feb 10, 2019)

I've replaced both batteries now with 100Ah Exide AGMs, which has ironed out a few minor errors which were coming up. I'm now just left with with fault 00272 which sounds like a wiring or connector corrosion problem, and then fault 01674 which is the brake booster ADR release switch. I'm off on my travels again for a couple of weeks, but I think I'm going to have to book it in to be done somewhere when I get back. I'm desperate to get these issues sorted and get ACC up and running!


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## Paximus (Aug 26, 2011)

Sorry not to respond sooner. I'm sure that the new batteries were long overdue and will help stabilise the car's operation in general, even if there are still one or two defects with that ACC.

It will also be interesting to see how the non-OEM wet cell batteries perform, as opposed to the AGM ones which are usually fitted to tackle heavy discharge recovery. Perhaps you'll get three years reliable performance. The battery charge controller is probably calibrated for AGM charging though.

Can you do another scan in a couple of weeks time when everything should be steady-state? I am really interested in that CAN Gateway fault. If the car is in any doubt about the reliability of the drive train bus then the engine ECU will certainly shut off the ACC as a precaution against legal liability for a self-drive issue.

It does sound most like there is a problem inside the Brake Booster, but I still would not rule out either the Brake Pressure Switch on the master cylinder or the Brake Pedal Travel sensor mounted on the brake booster. The ACC algorithms check each input's response against a prediction map, but it's quite plausible for the controller to come to a wrong conclusion.

Chris


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## ElSmoko (Feb 10, 2019)

It's been a while - I had to order a replacement brake booster from Germany, even VW over there didn't have one so it took about 4 weeks to arrive. It has now been fitted (a horrendously fiddly job apparently) and I got the car back last night. No change :facepalm:

I now only see the "electromagnetic interference" error, not the brake sensor warning I would sometimes see. I've also gotten rid of the CAN gateway error by recoding the module. It was coded for engine II, and had a couple of things I don't have fitted as well.

I'm not sure here to go now with the ADC error. I've spent £1,200 getting the brake booster changed out and a gearbox flush (which has made it silky smooth), and I'm not sure where to look next. I don't want to spend £300 on a second hand radar module just to see if that's the culprit, and I've never seen the control module available anywhere - I bet it's pricey from VW that's for sure.


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## Paximus (Aug 26, 2011)

It sounds like good progress to me. It's taken me 2 years to trace a radio fault in another vehicle, not a Phaeton, replacing the head unit, re-wiring the glass antenna cable, replacing the RF amp under the headliner, only to find another cut in the feed cable 2-inches further up the loom from the place I repaired on Day 1. Aargh...

You could try swapping out the radar unit with pot-luck on a used one, they are available on Allegro from £60 to £500, if you can persuade a vendor to post it to the UK. Here's the current list of availability: Allegro search for 3D0 907 567. (1 zloty is about £0.20). The logic for this is that 'Electronic interference' probably means that the radar signal is being blocked (by the unit itself). I assume no-one has painted over the radar cover on the bumper or obscured the central badge, if that's where your antenna is mounted.

I do have the original J539 Brake Booster Controller 3D0-907-563B that I swapped out of my 2005 car if you care to try it, again out of curiosity to see what changes occur in the error reports. PM me if you want to borrow it. However, I haven't researched if the drive train CAN-bus was changed on your 2008 car from mine, which would show up in a change of suffix letter on the part number.

Chris


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## ElSmoko (Feb 10, 2019)

Paximus you sound like my hero. What a nice chap, thanks for the offer of bits to borrow  I'm going back to the garage tomorrow evening hopefully, to have a re-scan and a think with the mechanic. I suspect the radar unit could be faulty, in which case there is one on ebay for £300, or I have a Polish reseller through work who I'm sure would gladly help me get one over there. Mine has the later, smaller radar unit so it's still about £250 I think, may be safer sticking with a UK unit.

I've had a look over the cabling and the radar unit itself, and it all looks fine. It looks through the badge, which I actually took off and cleaned with acetone to see if it helped. It didn't  The other suspect would be the control module for the ADR itself, but for some reason I suspect it's the radar unit up front. VW quoted me nearly £2,500 to replace it, I'll be annoyed if they were right that it was the fault, although I won't have spent that much money by the time I've chased all other avenues.

FYI the wet batteries I put in are doing well. I've noticed the car holds voltage better when turning on - the interior lights would dim a little sometimes when I first turned the key. In all honesty when I bought the batteries I was searching for AGM and thought that's what I'd bought, it hadn't even occurred to me they were flooded cells. Oops. If I had money to burn I'd love to try out some lithium batteries out of curiosity, although I'm not sure how they work from a BMS/charging perspective.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

ElSmoko said:


> FYI the wet batteries I put in are doing well. I've noticed the car holds voltage better when turning on - the interior lights would dim a little sometimes when I first turned the key. In all honesty when I bought the batteries I was searching for AGM and thought that's what I'd bought, it hadn't even occurred to me they were flooded cells. Oops. If I had money to burn I'd love to try out some lithium batteries out of curiosity, although I'm not sure how they work from a BMS/charging perspective.


That's encouraging to know that "regular" car batteries work. 

I would be scared a lithium battery would burst into flames since they seem to do that in cell phones, vape pens and laptops.


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## ElSmoko (Feb 10, 2019)

53PL-50AAA-VW611BAN said:


> That's encouraging to know that "regular" car batteries work.
> 
> I would be scared a lithium battery would burst into flames since they seem to do that in cell phones, vape pens and laptops.


Apologies, I'm about to go massively off-topic 

Regular flooded lead acid batteries will always work, as they are very similar - it's just a matter of voltages and current at the end of the day. The question is more about lifespan - an AGM is generally happier to discharge further and recover, but also they are charged at slightly higher voltage. As such, will the flooded battery be being overcharged. I've checked the voltage at the terminals and it's around 14.4-14.5v, which should be fine for a flooded battery, so I think it will be OK. As a good quality battery (at least in my experience), I'd hope they should last a sensible length of time, but they were only £100 per battery and have a 5 year guarantee so I can't really complain.

I'm a bit of a lithium fan-boi I think. It gets a lot of bad press in terms of danger. Yes, if you pierce a lithium cell with a nail for example, it will puff up and may catch fire. In a cell phone it's easy to drop it somewhere it shouldn't go, bend it, maybe puncture it and cause a fire. In a car, the chances of anything more than some vibration and jiggling about are minimal, so I'd say it's a pretty good spot for a lithium battery. They have significantly higher energy density as well, so it results in more capacity for less weight and space, with the ability to still supply massive current. They can also be charged harder than lead acid, and for many more cycles, so sounds good to me. Swapping from lead acid though requires a battery management system to manage voltages etc though, which is where a conversion becomes difficult. The fear of fire I find a little comical though, as completely untrained people routinely pump highly flammable liquid into their cars every day, storing them in a very dangerous manner - a container with highly explosive vapours, and nobody worries about that in the slightest. Yes, lithium batteries can burn, but so can petrol, and statistically I'd say petrol is far more dangerous and hazardous stuff.

That said, a proper 100kWh battery powering an electric car is a bit of a different matter - it's relatively a more significant lump of the car and therefore more prone to being bent/crushed/punctured, so design of the battery casing and the car around it becomes much, much more critical.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

ElSmoko said:


> Apologies, I'm about to go massively off-topic
> 
> Regular flooded lead acid batteries will always work, as they are very similar - it's just a matter of voltages and current at the end of the day. The question is more about lifespan - an AGM is generally happier to discharge further and recover, but also they are charged at slightly higher voltage. As such, will the flooded battery be being overcharged. I've checked the voltage at the terminals and it's around 14.4-14.5v, which should be fine for a flooded battery, so I think it will be OK. As a good quality battery (at least in my experience), I'd hope they should last a sensible length of time, but they were only £100 per battery and have a 5 year guarantee so I can't really complain.
> 
> ...


I don't know what the problem was with the phones that caught fire and I wasn't even thinking about Teslas. Do they have lithium batteries? 

Can the battery controller and the power supply control unit charge lithium batteries?


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## ElSmoko (Feb 10, 2019)

53PL-50AAA-VW611BAN said:


> I don't know what the problem was with the phones that caught fire and I wasn't even thinking about Teslas. Do they have lithium batteries?
> 
> Can the battery controller and the power supply control unit charge lithium batteries?


Pretty much any even partially electric car except some very mild hybrids and, weirdly, the Prius, will use lithium batteries. Nickel Metal Hydride ones were used in Prius's, and the old Honda Insight as well, and they don't last that long or store that much energy. But they are cheaper to replace.

Lithium batteries need to be charged differently to lead acid ones, so I'd say no, our battery controller etc won't handle it. That said, some of the lithium "direct replacement" batteries use different chemistry - LiFePO4 which gives you lower voltage per cell and is much closer to the standard 12v lead acid battery bulk charge and float charge voltages.

Lithium-ion cells are nominal 3.7v, maximum of generally 4.3v, so a "12v lithium battery" would be 3 cells in series, giving you 11.1v nominal and 12.9v fully charged, less than a lead acid cell.

The LiFePO4 cells are nominal 3.2v and 3.6v fully charged, so a 4-cell setup of those is almost exactly the same as a lead acid battery.

People often forget that a single lead acid battery cell only gives you 2v, so a normal car battery has 6 of them in series to give you the 12v we all know and love.


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## ElSmoko (Feb 10, 2019)

It's been a while since I've been trying to sort this issue, and I thought it best I put in an update.

I bought the car in August last year, and the ACC worked perfectly. After a couple of months or so, it would occasionally trip out and throw an error in the brake system, and the radar. This became more and more common, and eventually even on a power cycle the problem would persist. Clearing the codes would "fix" it short term, but it always came back after a few engine starts.

Initially I replaced both batteries, which cleared up some of my other fault codes, but essentially had no effect on the ACC situation. I checked and cleaned the connector on the radar unit itself, which seemed to help a little, but certainly didn't fix the issue. I have a fault code showing a problem with the brake booster switch, and an "electromagnetic interference" problem. I had the brake booster replaced for £720 for the part and around £300 fitting (horrendous job apparently), and this cleared the electromagnetic interference fault at first, and permanently fixed my brake booster error. Matt at Bishops Waltham Village Garage down here in Hampshire had the car back again, checked all the wiring and cleaned it as he went, and gave me the car back to see if the fault came back...

I've had the car a few weeks now, and I've done hundreds of miles in it, many of them with ACC doing the pedals for me. I don't want to say it aloud, but the problem has not come back once since that last visit. Matt thought the radar unit itself might be at fault, potentially overheating as it seemed to work perfectly from a cold start, but always fail after some driving, or on a "hot start". I've got a second hand replacement bookmarked on my browser just in case - a new unit is over £2,000, whereas used is around £300 - but I'm hoping I won't need to use it.

I love the car, and think ACC is a great feature. I'd love to tweak the software to smooth it out a little, but for all the motorway driving I do, especially in 50mph average speed limits, it's a true license-saver and stress reducer!


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## Paximus (Aug 26, 2011)

Thanks for posting that update! So many threads tail off into nothing, so it's welcome to hear what is happening.

Regarding the Phaeton's radar sensor, I used to have the odd criticism, but after using the BMW i3's camera-based system I now know how lucky we are. The camera-based system is not as reliable, in that it switches off suddenly just as I wish for a couple of seconds of support, eg turning into the sun or at night when it fails to distinguish car lights from other lighting.

In fact I gave up using the BMW camera-based system as it doesn't support my safety and just adds stress. The Phaeton system is reliable (except when it gives up in very extreme spray conditions, when a camera would also fail) and controls the car smoothly and predictably. I love it.

Chris


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