alexxxutz

Hello audiworld. This is my first thread here. I am an Audi A7 Sportback 2015 V6 diesel 320hp owner and had some issues with it.
The car started to report high coolant temperature (over 130 degrees) even immediately when I first start the engine in the morning. Obviously the coolant is not warm. Also the car has very low power due to software limitation.
On vag-com there is only one error about torque limitation due to high coolant temperature and P0429 error "Control module for catalyst heating (bank1)".
If I keep the engine running at high rpm (4-5k) for 20-30 seconds, the reported temperature is lowering instantly to 90 degrees and the car works normally, then randomly increses and decreases instantly.

I went to a garage and they replaced the coolant temperature sensor (OEM code 079919523) but the problem is still there. Nothing changed (possible the replaced sensor is also broken?)

Audi rep diagnosed the car and told me about G694 sensor that needs to be replaced (dont know the OEM code).

Any thoughs?

PS: Sorry for my bad english

wilco184

The temperature display on the dash is taken from G62 which is the main coolant temperature sensor (the one on the EGR cooler which it sounds like you've already had replaced) and G694 which is the coolant temperature of the block coolant circuit (this is on the front of the engine, to the right of the water pump). The fact that the issue exists as soon as you start the car suggests one of these sensors is at fault. G694 part number is 079919523 and G62 should have been 079919523B.

Thanks,

Matt.