About 3 weeks ago my MIL (Malfunction Indicator Light) turned on. Did a scan and here's what I found.

Last night, I did some investigation using VCDS. The car had been off for 2 days. I monitored the Coolant Temperature Sensor, G62 as it warmed up at idle in the driveway. Temperature steadly rose from the ambient temperature 0C to 87-89C over the course of 15 minutes.

Today, on the way to work (30 minute drive mostly in town), the MIL came on again. Coolant gauge in the middle less than 15minutes into the drive.

I did a scan tonight after I got home (left the car running and grabbed the laptop). Scan came up at first 87C then 7C, 8C, 9C. Shut the car off, then 4C, 5C etc. See "measuring blocks.jpg". Coolant temperature guage was in the middle. Oil temp 160F.

So it looks like my Coolant Temperature Sensor is bad. I checked the sensor, looks original with the car, black. I also have full service records since mile 0, never been replaced.

No issues with cabin heating.
Car sounds/runs fine.

53k Miles on Odometer
2004 A6 2.7T

Before I spend the $20 and more importantly, the time, does anyone see differently?

 

Agree. A good starting point, for the money. Put a ECT sensor in it, clear the faults and ship it.

 

I bought the parts from the local dealer $40 and did a write up for others.

https://www.audiforums.com/forum/aud...1/#post1360310