Hello,

I have replaced my coolant temp sensor today. But it still sticks between 80 and 90. It didn't reach 90 . Do I need to reset the coolant temp sensor error code using VAG-COM?

Thank you

Should be no need specifically to reset any codes to get the "correct" temperature displayed. Maybe the replacement sensor is missreading?

Is It a genuine temp sensor that you have fitted? If so have you cleared any faults off the ecu?

How long does it take to heat up. I think thermostat is stuck open personally if it won't get up to full temps.

It is a genuine one from VW. Rightnow I do not have VAG-COM. So I haven't cleared coolant temperature sensor fault from ECU. It takes upto 5KM to reach between 80 and 90. Any ideas.

My 110TDi takes about 5-6 minutes before the guage indicates the coolant temp is up to 90 deg C, so that does not sound unreasonable.

When I idle the car for more than 20 minutes, the guage didn't move more than 80. I will change the Themostat during next service schedule. I hope this problem will not harm the engine. Please clarify.

The sensor had two outputs, iirc. One for the guage and one for the ECU. If in theory it is undereading then possibly it might affect things like the fans cutting in. I am not in a position to clarify though - most people say their guages read 90 pretty much all the time (apart from a few minutes after a cold start).

The sensor had two outputs, iirc. One for the guage and one for the ECU. If in theory it is undereading then possibly it might affect things like the fans cutting in. I am not in a position to clarify though - most people say their guages read 90 pretty much all the time (apart from a few minutes after a cold start).

Could having the faults on the ECU be causing it though? IIRC as I was watching Shark_90 whith his vag com, I had two faults in regarding my faulty temp sensor & one was in the Instrument menu of vag com.

Rather than randomly changing components why not verify the fault and then diagnose it.

Does the thermostat open? Is the engine getting up to temperature correctly?

After finding coolant temperature sensor error fromVag-Com only, I have changed the sensor. I haven't found any sort of performance degradation before changing the sensor too. The car is not obtaining the proper temp 90. It stuck between 80 and 90 only. Is there any method to detect thermostat is stuck open?