# V10 TDI - ECU Replacement - Both Master (01) and Slave (11)?



## Appaz (Oct 30, 2009)

Hi guys, 

I have V10 Diesel. 
This engine has 2 ECU's (Engine Control Units). 
One of mine ECU's got toasted. 
So service guys tell me it is impossible to change just one ECU and get it familiar with another one to work well togerther. I have been told I have to replace both ECUs at once. 

Could this really be true? 

_Update question:_ 
I am thinking of getting two ECU units of salvaged phaeton, identical to my car. They both are fully functional. 
Is there any option how to tell which one this cars ECU's is primary ECU, which one is secondary ECU? 

Thanks, 
Ed.


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## PanEuropean (Nov 3, 2001)

Hello Ed: 

I don't know if it is necessary to replace both the master (01) and the slave (11) engine controllers at the same time if only one of them is inoperative. 

I *do *know that the engine controller is a participant in the anti-theft system, and it is very probable that if you replace one or both of the engine controllers, you will need to have the ignition keys and the immobilizer system (anti-theft system) re-adapted. Generally this means that you have to take the car to a VW dealer, where they can hook the car up to their diagnostic scan tool (VAS 5052, etc.), and at the same time hook their diagnostic scan tool up to the VW computer system via internet. 

So, you might want to do a little bit more investigation about what the re-adaptation requirements are before you replace the controller, otherwise, you might find yourself with an inoperative vehicle because the anti-theft system will not permit it to start. 

Be aware that when the anti-theft system is (re)adapted, you must have all the vehicle keys present. If any keys are not present at the time of the adaptation, they will be disqualified and will no longer work. 

Michael


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## Appaz (Oct 30, 2009)

Thank you for your response, Michael. 

I have to say, car already is at official VW service, and they are taking care of it. 
So no worries about re-adaption of keys. 
I just wanted to know, do they charge me right (both ECUs to change?). But, as far as I may guess, as far you and google is telling, this must be true. 

So I have another question, as edited first post above - how to detect, which one of used ECUs was primary, whichone was secondary... 
Any hints? 

Thanks, 
Ed.


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## PanEuropean (Nov 3, 2001)

Hello Ed: 

I believe that both of the controllers (the master, which is 01, and the slave, which is 11) are the same part number. When the controllers are installed, the vehicle recognizes which one is installed in the Controller 01 (master) position, and which one is installed in the Controller 11 (slave) position. This is probably accomplished by the controller looking at the vehicle wiring harness and finding a configuration setting (for example, one pin to ground or something similar to that idea) that tells the controller what role it should play. 

Below is an excerpt from a VAG-COM scan that I made of a V10 Phaeton a few years ago. You can see that the part numbers and hardware/software identification is the same for both controllers. 

Although is is possible that it may only be necessary to replace one controller (the defective one) if the dealer is able to obtain a replacement controller that is exactly the same part number *and *hardware identification *and *software identification, it is also possible that the dealer cannot obtain an exact matching controller - hence the reason why they are telling you that it is necessary to replace both controllers. In other words, they may not have to replace both controllers because both are defective, but they may have to replace both controllers in order to ensure that they both match each other exactly. 

On this matter, I would be inclined to give the dealership the benefit of the doubt. 

Michael 

*Sample Controller Listing - V10 TDI* 
Address 01: Engine Labels: None 
Part No SW: 070 906 016 B HW: 028 101 073 7 
Component: V10 5,0L EDCA000AGMª5726 
Coding: 0000175 
Shop #: WSC 01065 


Address 11: Engine II Labels: None 
Part No SW: 070 906 016 B HW: 028 101 073 7 
Component: V10 5,0L EDCA000AGSª5726 
Coding: 0000175 
Shop #: WSC 01065


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## Appaz (Oct 30, 2009)

OK, thank you. 
So far I understand. 

But, what I do not get.... could you please explain, if I purchase two used ECU's, and seller does not know, which one was master, which one was slave. 
So my repair service guys will get these ECU's, which look identic, and will not know, which one was master, which one was slave.... 
Will they be able to detect which was master, which was slave - so they know where to plug each ECU? 

----- 

Edit: 
I think I got it: "that tells the controller what role it should play.". 
So no matter what type controller was on previous engine - master or slave? You "just plug them" and they auto-detect their new states - master / slave? Did I understand it correct? 

Thank you.


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## PanEuropean (Nov 3, 2001)

Ed: 

I am guessing here, but it is an educated guess, based on how the car recognizes other duplicate controllers. 

By example, I believe that the controllers for the left and right xenon headlights are the same part number. But, when you install the controller, the vehicle assigns the appropriate controller number (29 for the left light, and 39 for the right light). I suspect that this is accomplished by the wiring harness in the vehicle - in other words, there is probably some kind of tiny difference in the pinouts of the wiring harness on each side, such as one pin leading to a ground on one side, but not on the other side. 

I do know (for sure) that on the aircraft that I am responsible for, we install two Data Acquisition Units, one for the left engine and one for the right engine. Within the wiring harness of the aircraft, we supply a ground to one pin of the connector for the left engine DAU, but we do not supply a ground to the same pin on the right engine DAU. The DAU itself (analogous to your engine controller) has firmware in it that tells it that if it detects the presence of a ground on a certain pin, then it is installed in the left engine position, and if there is no ground detected on that pin, then it is installed in the right engine position. The DAU then modifies the way it operates according to what side of the aircraft it has been installed in. The same part number is used for each side of the aircraft, in other words, both DAUs are identical. 

I am guessing that the Master and Slave controllers on the V10 and W12 engines probably use a similar scheme for functional identification. The only reason that these two engines need two controllers is that one single Bosch controller cannot manage more than 8 cylinders - so, rather than creating a single new, expensive, and low-demand controller that can manage 10 or 12 cylinders, VW just splits the work up between two controllers, same way my employer does with the aircraft DAUs. 

Michael


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## Appaz (Oct 30, 2009)

Thank you. 

Based on what you tell and on fact that visually both ECUs are really identical, there must be no problem with installing them just in any of two possible position. 

Otherwise, if they would be strictly one as a slave, other one as a master, they would be made so it is possible to identify their role. Factory code, a writing on unit sticker, different plugs, whatever. 

I am buying thses two ECUs from one car same as mine and will see how it goes. 
Will report after. 

Thank you once again.


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## apper01 (Aug 14, 2010)

my suggestion is that the phaeton uses a fixed bus topology and as such the car scans the bus at startup and all attached modules report back in sequence and get their bus address accordingly and identify themselves almost like a pci bus on your pc.

Aart.


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## Spacewalker (Nov 23, 2009)

I have to also replace ECU,but unfortunatelly spare parts garage have only one, and they dont know if is master or slave. Prepare this with PIN is no problem, but nobody know is really matter master and slave, or no different. Engine working with 5 cyl 1st, and 5 cyl 2nd. Not 8 cyl 1st and 2 cyl 2nd. Communication is beetwen them, so when one Glow Plug is faulty, both see the problem. Im gonna buy one nad analize software.

Who can recognize which one is which ?
Both from one car


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## mog3618 (Dec 14, 2006)

PanEuropean said:


> Hello Ed:
> 
> I believe that both of the controllers (the master, which is 01, and the slave, which is 11) are the same part number. When the controllers are installed, the vehicle recognizes which one is installed in the Controller 01 (master) position, and which one is installed in the Controller 11 (slave) position. This is probably accomplished by the controller looking at the vehicle wiring harness and finding a configuration setting (for example, one pin to ground or something similar to that idea) that tells the controller what role it should play.
> 
> ...


Sorry to bring this back from the grave... I am stuck in a bind and this thread is the most relevant to my issue that I have found.

I am dealing with an 04 Tuareg which has the V10 tdi. The car came to me dissasembled and I have it back together but I am getting a codes listed below..

18332 - Controller Pin Coding 
P1924 - 000 - Implausible Signal - MIL ON
Freeze Frame:
RPM: 0 /min
Torque: -489.8 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 12.62 V
Bin. Bits: 00000000
(no units): 0.0
(no units): 0.0

18048 - Internal Control Module 
P1640 - 000 - EEPROM Error
Freeze Frame:
RPM: 0 /min
Torque: 0.0 Nm
Speed: 0.0 km/h
Bin. Bits: 00000000
Bin. Bits: 00000000
Bin. Bits: 00000000
Bin. Bits: 00000000
Bin. Bits: 00000000

I fear the ECM's are in the wrong location but I am not certain. You stated that the locations 01/11 assigned when they are plugged in. If I swap the locations will I set off the immobilizer?


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## Paximus (Aug 26, 2011)

Hi Frank,

Although this is a Phaeton forum, the Touareg shares 90% of its systems with the Phaeton, so I hope someone here can help you.

I was under the impression that once the engine controllers were installed and paired together the pairing was permanent. In other words, the one that is instructed to be Master at address 01 by being plugged into the Master socket will code itself accordingly, and the slave at address 11 in the Slave socket will permanently set itself up for that role.

Could your ECUs have been taken out and replaced in the wrong sockets? They are visually indistinguishable.

If the ECUs did not come with that engine, then their CAN-bus security keys will not match the other drive train bus components and they will not allow the engine to run. This is because it is only permitted to change one of the four security-coded components before having to carry out a re-coding of the bus security. If more than one is changed, the security key on the drivetrain CAN-bus must be reset at a dealer, using an on-line link to VW HQ.

You did not post the part of the scan that relates to the controller addresses or the drivetrain bus. Feel free to post a full scan if you think that will clarify things a little, especially whether any other controllers are unhappy.

Chris


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