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View Full Version : DIY Video: Trans Cooler Valve replacement (Fix code P2753)



AudiC7Owners
02-19-2021, 02:04 PM
While I was able to get my car on a lift to install my new exhaust, I took advantage of the time and also replaced my Trans Cooler Valve, otherwise known as your N82 valve. This is a very straight forward and simple replacement that will save you a LOT of money in a few ways. You will only be spending about 150$ in parts, and about an hour of your time vs paying 1500$ at the dealership (That's the highest price I've seen someone pay so far).

Signs of Failure:
-You get code P2753
-You smell a faint coolant smell near the drivers side door, but don't see any leaks anywhere
-You see small puddles of coolant under the car on the driver's side right under your downpipes (Like silver dollar sized puddles, not much, and doesn't happen all the time).

The reason replacing this valve when it goes bad is so important is because, if neglected, it can result in catastrophic damage to your TCU. Then, instead of spending 150$ in parts and an hour of your time, you will be out thousands of dollars replacing your TCU or your Transmission. The way this happens is that when the valve fails, coolant migrates out of it via the electrical connector plugged into it. It then works through that up the wires of the wiring harness. If it makes it all the way to the TCU, then you are screwed.

Tools List:
-Work Light
-Jack stands & Jack
-T30 torx bit (I think... might be smaller)
-Locking hose clamps (Like these... I got 2 for 11$/each at harbor freight https://amzn.to/3ueG0wN)
-Wire cutter/stripper
-Heat Shrinked crimp connectors
-Pliers
-Something to catch dripping coolant
-Eye protection

Parts Needed:
-Valve: 4H0121671D (I suggest you buy from FCP Euro for their lifetime warranty)
-Connector Housing: 8K0973702
-Repair Wire: 000979025EA
-Wire Weather Seal: 4B0972740

Noteworthy Information:
-In the video, there are lots of things removed that you probably don't have to remove. This is because we were working on multiple things at once on the car. You need to remove the belly pan that gives you access to the valve. You MIGHT not have to remove the cross brace like we did, but it may give you more room for access to the valve. Be careful of the wiring harnesses attached to it if you do remove it.

-Watch the entire video with the volume on so you can listen to what my friend is talking about. He explains how to determine how much of your wiring harness you need to replace.

-Make sure you check what side each wire plugs into the oem connector before you cut it. There is a Green wire & a purple (or black) wire. The connector is labeled "1" & "2". Make note of which color goes to which number, because your repair wire is yellow. If you plug them into the wrong sides then you will get a fault code.


https://youtu.be/pRMSKLgIi9Q

donimator
06-16-2022, 05:00 PM
Any idea what the supply voltage should be to the valve? I have 3.3 volts

morski
06-17-2022, 04:02 AM
Blue wiring seal is 4B0972740 But check the correct cca of cable you are using as there are other size seals available. Alway worth putting these back on as they are cheap and a bit more peace of mind

miahshodan
04-19-2023, 04:52 PM
I had the same error on my 2012 A6 3.0T. ordered the wiring kit, new plug, etc. But when I took off the valve last night, there was no coolant in the wiring, so I just replaced the valve and cleared the code. So far so good. Do you know if the same fault would come with no wiring failure?

AudiC7Owners
04-19-2023, 07:09 PM
I had the same error on my 2012 A6 3.0T. ordered the wiring kit, new plug, etc. But when I took off the valve last night, there was no coolant in the wiring, so I just replaced the valve and cleared the code. So far so good. Do you know if the same fault would come with no wiring failure?

Yes. It would be the same fault if the wires were fine.

dspl1236
07-02-2024, 06:28 AM
Thanks for the video, my 2013 just popped this code.

Newbie_from_NJ
01-10-2025, 12:18 PM
Thanks for the insight and the amazing video as always!

My Check Engine Light just turned on a day ago with this code on my 2013 A6 3.0T with 111K miles. Fortunately, I saw your video and realized the consequences with the TCU if ignored. That said, I only drove the car 20 miles after the light came on. Your exact parts have been ordered and I won't even risk driving it to the shop. I'll have it towed there just to be on the safer side, considering I also have an engine code P1624 MIL Request Signal Active (Check TCM for errors too!) (both codes came out at the same time.) I ran a VCDS full scan last week and they weren't there then.

Below is a pic of the coolant leak found in my driveway. Seems significant, no? Bottom of pic is where the front of the car would be.
https://www.dropbox.com/sc/e81260o5czkhn3j/AAAq53Rc0LHFU2z0S0KOvDzma

Newbie_from_NJ
01-29-2025, 08:24 AM
Update: I replaced the coolant valve, connector and wires. That resolved the CEL, Engine and Auto Trans DTCs. Thanks again!