[WolverineFW]

The wire was providing voltage to the relay....I should say across the relay coil. I believe it is a switched ground on that circuit. The relay was not faulty and stuck. The fan relays on mine were in the external relay box under the cowl on the other side. There Is a removeable cover to get at it.

I bought an oscilloscope to investigate further but then the problem stopped.

I never took off the wipers or removed the entire cowl.

I just moved the wipers out of the way and popped the cowl up enough to get at it.

Cut slots in the security screws with a Dremel and used a flat screwdriver to turn them out.

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[bcredeur97]

I feel like this needs to be addressed:

Heat delivery temperature in cooling system: -273.1 °C

Anyone know what sensor this is? There's clearly something wrong with it anyway so I feel like that should be addressed before I move forward with anything else. It's the only super obvious data point I have currently

 

[WolverineFW]

I feel like this needs to be addressed:

Heat delivery temperature in cooling system: -273.1 °C

Anyone know what sensor this is? There's clearly something wrong with it anyway so I feel like that should be addressed before I move forward with anything else. It's the only super obvious data point I have currently

That is an absolute zero reading. I think I saw that too. I believe it might not apply to this engine.


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[bcredeur97]

That is an absolute zero reading. I think I saw that too. I believe it might not apply to this engine.


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maybe so.. but check this out:

A new day.. a new code! - AudiWorld Forums

A7 - A new day.. a new code! - Picked the car up this morning from the garage after it being in for a week because of oil leak from timing chain cover. I noticed on the way hom there was a warning triangle for the engine start/stop function. I cleared a load of stored codes and this one lingers...

www.audiworld.com

that looks like an Audi 3.0L TDI motor. I know it’s a little different but ours could very well have that same sensor in that spot, so I’m going to check and see if mine does and unplug it to see what, if anything, changes. His was actually unplugged in his case and he too had that crazy reading.

but if it’s indeed no applicable, I need some evidence of that.. im going to check if that’s a measuring block and I can see if anyone else can maybe look at their working car and see if it has that same absolute zero value

 

[WolverineFW]

My motor is an Audi 3.0L TDI...[emoji6]

maybe so.. but check this out:

A new day.. a new code! - AudiWorld Forums

A7 - A new day.. a new code! - Picked the car up this morning from the garage after it being in for a week because of oil leak from timing chain cover. I noticed on the way hom there was a warning triangle for the engine start/stop function. I cleared a load of stored codes and this one lingers...

www.audiworld.com

that looks like an Audi 3.0L TDI motor. I know it’s a little different but ours could very well have that same sensor in that spot, so I’m going to check and see if mine does and unplug it to see what, if anything, changes. His was actually unplugged in his case and he too had that crazy reading.

but if it’s indeed no applicable, I need some evidence of that.. im going to check if that’s a measuring block and I can see if anyone else can maybe look at their working car and see if it has that same absolute zero value

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[WolverineFW]

Usually if a sensor reads absolute zero, it is an open circuit...

maybe so.. but check this out:

A new day.. a new code! - AudiWorld Forums

A7 - A new day.. a new code! - Picked the car up this morning from the garage after it being in for a week because of oil leak from timing chain cover. I noticed on the way hom there was a warning triangle for the engine start/stop function. I cleared a load of stored codes and this one lingers...

www.audiworld.com

that looks like an Audi 3.0L TDI motor. I know it’s a little different but ours could very well have that same sensor in that spot, so I’m going to check and see if mine does and unplug it to see what, if anything, changes. His was actually unplugged in his case and he too had that crazy reading.

but if it’s indeed no applicable, I need some evidence of that.. im going to check if that’s a measuring block and I can see if anyone else can maybe look at their working car and see if it has that same absolute zero value

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[WolverineFW]

Another thing I remembered was that I ran output tests on both fans and they both ramped up and down properly as I changed values.

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[bcredeur97]

Another thing I remembered was that I ran output tests on both fans and they both ramped up and down properly as I changed values.

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mine doesn’t do that. It doesn’t respond to the output test at all. The fan just runs at full speed no matter what

that is likely pretty telling obvious communication issue between fan and ECM

ill have to check those ECM connections like you suggested and go from there.

 

[MidnightTouaregV8]

Please find a good known unit (ECT) and compare values with existing ECT (you'd have to remove it)
Others suggested checking the wiring. Don't dismiss it. The culprit could be a corroded connection.
ECT is a thermistor and changes resistance depending on the temperature of the coolant. A simple boiling water test will reveal if there is an issue with Ω reading.
I am not familiar with the VW TDI cooling system operation. But I reckon it has a similar protection mode in case of ECT is compromised.
Even at full bore, a cooling electric fan can't cool the radiator below or at ambient. It just can't.
The exception is when ambient temps below 0°C. In his case, it is a warm winter day at 11°C.

When it comes to diagnostics, people tend to overthink. Don't overthink, follow the breadcrumbs scan data give you.

 

[WolverineFW]

mine doesn’t do that. It doesn’t respond to the output test at all. The fan just runs at full speed no matter what

that is likely pretty telling obvious communication issue between fan and ECM

ill have to check those ECM connections like you suggested and go from there.

If you cannot control fan speed...I would be looking at the fan motor controllers.

You need to check the signal coming to the controller and see if it is being commanded to run 100 percent.

If one or both are damaged....the fans can run at full speed. One fault on can back feed the other. There are a couple good You tube videos on testing VAG fan controllers.

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[SaVAGeSoot]

Well.... that was a good 🏒 game! 🏆🥇

Regarding suggested flaky\wonky ECTs.... log\graph their values during your drive... this should clarify if one of the temps jumps around quickly or inexplicably due to the failure, connection, etc.

I think your problem is on pin #4 as others have also suggested.
It should go to pin #48 on the 105 pin connector on the ECU.

 

[SaVAGeSoot]

I unfortunately don't have any codes from before yesterday saved. Oddly enough the one I do have saved is the one from 111k miles... but that was before I had this issue, and it has no codes

VCDS saves all AutoScans regardless of you asking it to or not... so any time you ran one, there's a record saved.
Poke around your VCDS folder to find them, or look at the manual or RT youtube vids.... I can't recall where I saw that info at the moment.

 

[SaVAGeSoot]

Happy Friday!

 

[SaVAGeSoot]

VCDS saves all AutoScans regardless of you asking it to or not... so any time you ran one, there's a record saved.
Poke around your VCDS folder to find them, or look at the manual or RT youtube vids.... I can't recall where I saw that info at the moment.

I knew I wasn't making this crap up.....

Update: VCDS now has a Scans folder (typically C:\Ross-Tech\VCDS\Scans ) that should save a copy of the Scan even if you don't explicitly Save or Copy it anywhere. "Even if you don't believe in Saving Auto-Scans, Auto-Scans believe in saving you!" We still recommend you save scans somewhere so they don't get lost in computer moves or updates.

 

[SaVAGeSoot]

@bcredeur97 disconnect connector #7 and clean\inspect it. Pay special attention to pin #3.

 

[bcredeur97]

@bcredeur97 disconnect connector #7 and clean\inspect it. Pay special attention to pin #3.
View attachment 255386

so I think you got me on the right track.

i opened the fuse panel and there was liquid dun dun dunnnnn

But it’s actually someone’s fault — someone’s been in here before, the rubber seals were not seated properly.

check pics:

 

[bcredeur97]

More carnage

 

[SaVAGeSoot]

And people wonder why I hate big red shoe wearing butchers.

 

[bcredeur97]

And people wonder why I hate big red shoe wearing butchers.

I’m going through every single connector

cleaning it with electric contact cleaner.
Using a heat gun to carefully dry it out completely
Putting a little bit of dielectric grease.

And praying! Lol

 

[bcredeur97]

The connectors are cleaning up nicely. Just a little worried about the small pins I’m not sure if my brush is getting well enough in there