# Engine Coolant Temp. Sensor (G62)



## n968412L (Apr 23, 2009)

Got an incipent problem.

When the engine is warming up - say within the first ten minutes... or nearer about five.... as the coolant temperature gets to about 60°C, the coolant temperature gauge suddenly behaves erratically - and often drops completely to zero for a few seconds, and then recovers. Usuall twice When the engine is fully warm it sits rock steady at 90°C. When it's wavering around 60°C, even if it's not moving wildly, it is hunting, with a variation of about the width of the needle.

And when it falls to zero, if I'm accelerating at that time, the engine behaves strangely, surges, and I have had a couple of very very rough gear shifts. On one occasion PRNDS lit up and I had to cycle the ignition to get it out of limp mode.

It looks as though it just might be the temperature sender.... but who knows on a Phaeton.

Scan below. This is composite of two scans as I always have trouble scanning this car, although individual controllers seem accessible OK. I've checked all controllers and these are the only ones with fault codes.


Friday,31,January,2014,18:11:54:37747
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: 12.12.0.0
Data version: 20130910


VIN: WVWZZZ3DZ58004546 License Plate: OY05XMZ
Mileage: 97380km-60509mi Repair Order: 


Chassis Type: 3D (3D - VW Phaeton (2002 > 2006))
Scan: 01 02 03 05 06 07 08 09 11 15 16 17 18 19 29 34 36 37 38 39
46 47 68 71

VIN: WVWZZZ3DZ58004546 Mileage: 97380km/60509miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: None
Part No SW: 070 906 016 B HW: 028 101 073 7
Component: V10 5,0L EDCG000AGMª5726 
Coding: 0000175
Shop #: WSC 01065 000 00000
VCID: 0F26BDB71DCE1F661D9-513C

2 Faults Found:
17075 - Fan 1 Control Circuit 
P0691 - 000 - Short to GND
Freeze Frame:
RPM: 588 /min
Torque: 79.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 13.22 V
Bin. Bits: 00001100
Temperature: 77.4°C
Duty Cycle: 11.2 %

16502 - Engine Coolant Temp. Sensor (G62) 
P0118 - 000 - Signal too High - Intermittent
Freeze Frame:
RPM: 1554 /min
Torque: 268.6 Nm
Speed: 14.3 km/h
Load: 28.6 %
Voltage: 13.07 V
Bin. Bits: 00001100
Temperature: 27.0°C
Temperature: 34.2°C

Readiness: 0 0 X X X 

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: None
Part No SW: 09F 927 760 B HW: GS1 9.0 4.1 
Component: AG6 09F 5,0L V10TDI 1202 
Coding: 0001101
Shop #: WSC 00000 000 00000
VCID: 30641E4BA0B0209E243-5120

1 Fault Found:
17167 - Shift Monitoring 
P0783 - 000 - 3-4 Shift - Intermittent
Freeze Frame:
RPM: 1760 /min
RPM: 1664 /min
RPM: 1120 /min
(no units): 42.0
(no units): 25.0
Temperature: 39.0°C
T.B. Angle: 28.2°
Voltage: 12.40 V

------------------------------------------------------------------------------
-------------------------------------------------------------------------------
Address 05: Acc/Start Auth. Labels: 3D0-909-13x-05.lbl
Part No SW: 3D0 909 135 N HW: 5WK 470 21
Component: Kessy 6610 
Revision: 66105312 Serial number: VWZ3Z0E1312413
Coding: 0004328
Shop #: WSC 01065 000 00000
VCID: 30641E4BA0B0209E243-513C

Subsystem 1 - Part No: XXXXXXXXXXX 
Component: ELV XXXX

2 Faults Found:
00165 - Switch for Transmission Position P/N 
007 - Short to Ground - Intermittent
00172 - Key 2 not learned 
008 - Implausible Signal - Intermittent

-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
Address 09: Cent. Elect. Labels: 3D0-937-049-V1.clb
Part No: 3D0 937 049 H
Component: STG.Bordnetz 5101 
Coding: 0000003
Shop #: WSC 00199 210 83391
VCID: 2F661D37BD8E3F663D9-513C

1 Fault Found:
00907 - Intervention load Management 
000 - -

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
Address 18: Aux. Heat Labels: None
Part No: 3D0 815 005 AA
Component: Standheizung 2426 
Shop #: WSC 01065 000 00000
VCID: 5CBC9AFB9CB8F4FEA8B-513C

Subsystem 1 - Part No: 3D0 815 005 AA
Component: Standheizung 2426

3 Faults Found:
01415 - Recirculating Pump (V55) 
010 - Open or Short to Plus - Intermittent
01299 - Diagnostic Interface for Data Bus (J533) 
013 - Check DTC Memory - Intermittent
00664 - Fuel gauge 
002 - Lower Limit Exceeded - Intermittent

-------------------------------------------------------------------------------
Address 68: Wiper Electr. Labels: Redir Fail!
Part No: 3D2 955 120 
Component: Front Wiper 3000 
Shop #: WSC 00000 000 00000
VCID: DFC62DF70DAE6FE64D9-5120

Subsystem 1 - Part No: 3D2 955 120 
Component: Front Wiper 3000

1 Fault Found:
65535 - Internal Control Module Memory Error 
015 - Cannot Be Tested at this Time - MIL ON

-------------------------------------------------------------------------------


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## PanEuropean (Nov 3, 2001)

Hi Mike:

I think you are correct in your diagnosis that the temperature sender is failing - the symptoms you describe and the intermittent nature of the fault recorded in controller 1 support your diagnosis. I'm not sure where that component is located on a V10 Phaeton - perhaps Chris can help out with the location. Hopefully it is in a location that is easy to access. I doubt that it is a particularly expensive part, I don't think it does anything other than measure temperature (in other words, it's not a actuator).

The 'hard' failure of the number 1 cooling fan is of concern - it's not going to cause you problems in February, but it might cause you problems come May or June if you get stuck in traffic. I suspect that the coolant temperature sender is likely located somewhere near to the radiator, that means that you won't need to pay two complete labour charges if you get these two faults fixed at the same time.

I can't comment on the fault in the transmission controller, that is out of scope of my knowledge.

The fault in the KESSY (controller 05) about the transmission lever position uncertainty might have to do with dirt or a spill of liquid into the electronics that surround the shift lever. Undoubtedly that is related to you occasionally seeing PRNDL light up - PRNDL will light up all at the same time if the car cannot determine what position the shift lever is in. Have a look at this discussion: Transmission (any version) - PRNDS lights up in display . If you are lucky, you will only find dirt or spilled liquid that is preventing that little sliding plate from freely moving around. If you are unlucky, you will find the sliding plate broken (that necessitates replacement of the whole electronics board, about USD $220 for the part). The post about Retrofitting Keyless Start to Phaetons that are equipped with Keyless Entry provides full instructions for parts removal to get in there and have a look at things, and it also provides quite a bit of elaboration (beginning with post #51 on page 2) about that sliding plate.

The rest of the fault codes are, I think, not worthy of serious investigation - unless they persist time and time again, my guess is that they are the consequence of a momentary low voltage state and can be safely disregarded.

Michael


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## n968412L (Apr 23, 2009)

The sender seems to be right at the front and top of the engine... could not be better placed! However I cannot see how to unclip the wiring connexion to it... no obvious little lugs to prise out of the way... and I'm reluctant to pull any harder than I have... I think there must be a catch somewhere....

No 1 fan doesn't seem to be a problem. It's always been like this from when I got the car (two years ago today as it happens) and in the summer the fans run. I've been meaning to pluck up courage to exercise all the functions on the engine controller, which includes the fans... but never quite managed it. But I don't think it's a factor in this problem. However if I succumb to taking it somewhere... it might be worth doing.

I don't think there's anything wrong with the gear stick lever electronics. Nothing been spilled there in the two years I've had it - and that particular fault has been occurring intermittently again for the two years I've had the car. But I've never had PRNDS before on this Phaeton. And the odd thing is, it came during the temperature gauge being on zero just as I accelerated to join motorway traffic.

There is a deeper worry I have... this car is harder to scan than my other one - lots of controller time outs etc. And I've had couple of MIL incidents on it which have both gone away, but the cause seems to be lack of communication between controllers.

I think a G62 sender is only going to be a few quid - so I'll probably buy one and try and pop it in soon...


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## PanEuropean (Nov 3, 2001)

n968412L said:


> ... this car is harder to scan than my other one - lots of controller time outs etc....


Mike:

Do you scan it with the engine running? That is what I always do - it seems to eliminate communication errors, missed controllers, etc. 

Michael


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## n968412L (Apr 23, 2009)

PanEuropean said:


> Mike:
> 
> Do you scan it with the engine running? That is what I always do - it seems to eliminate communication errors, missed controllers, etc.
> 
> Michael


Absolutely. I've too much respect for the LH battery to do it any other way. I had a good e-conversation with Chris Paximus about this a while ago... I suspect I might have some gremlins, possibly corrosion, in some of the can bus connexions. I need to have a look sometime soon.... when the weather's better.

Regards

M


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## n968412L (Apr 23, 2009)

Think it's solved....

New sender (£32) installed. The location could not be in a better place. Top of the engine at the front.. and so high up that no coolant runs out!

But what a swine to fit. I couldn't understand why I couldn't get it in... till I put a bit of silicone lube on the o-ring. Then it went in so easily I couldn't actually see why it didn't go in before.

Now the temperature readings from cold increase monotonically... ie it doesn't have excursions back to zero. And subjectively it drives much more smoothly when the engine is cold... I'll test that out a bit more... 

Happiness restored.

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## Gabs08PHTN (Jan 6, 2011)

Congratulations Mike! 
Good to hear that it was an easy fix. 
On the V6TDI it sits not as conveniently. It is located behind the engine, on the UK's driver's side , between the engine and the front bulkhead. So I hope it takes a long time for it to fail!

Gabriel


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## n968412L (Apr 23, 2009)

Gabs08PHTN said:


> On the V6TDI it sits not as conveniently. It is located behind the engine, on the UK's driver's side



Yes.. I had a quick look. One of the very many advantages of owning a V10. 

Regards
Mike


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