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Peterkmiles
Peterkmiles, UK Car Mechanic
Category: Audi
Satisfied Customers: 41
Experience:  13 years experience at the highest level of automotive technology
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my temp gauge is permenatly reading hot even when engine is

Customer Question

my temp gauge is permenatly reading hot even when engine is off and cold
Submitted: 3 years ago.
Category: Audi
Expert:  Peterkmiles replied 3 years ago.
Hi,

Could you please provide your vehicle details?

Best Regards
Customer: replied 3 years ago.


Audi 2.0 A4 2001

Expert:  Peterkmiles replied 3 years ago.
This fault tends to suggest the ect (engine coolant temperature) sensor is earthing out. It could be a faulty temperature sensor, an electrical fault (wiring or ecu).

An easy test is to disconnect the ect sensor and see if this changes the reading on the dash.

If it does then below Is the process for replacing the sensor.

I had to remove the airpipe going across the back of the engine bay after removing the engine cover.

The wiring must come off first and the replacement sensor attached, it'll make the replacement faster and easier when the new one is connected and ready to go in.

To take off the wiring, I had to use a thin screwdriver to push the slot of the plug towards the centre of the wires and it pulled free. I then attahced the new sensor to the wires. Next, afte much struggling I managed to get that small screwdriver under the existing sensor and pulled the plastic clip down and almost out, and removed it carefully by hand. You probably need to have a replacement clip to hand in case of breakage. Before pulling the dud sensor out, I opened the coolant reservoir cap and squeezed the top radiator hose as flat as I could and put the coolant reservoir cap back on - keeping a low vacuum in the system. Back down to the sensor. I put the new o-ring on the new sensor, pulled the old sensor out and quickly sticking a finger into the opening to recover the old o-ring.
Quickly putting the new sensor and o-ring into place, reseated the plastic clip, put back in the air pipe, put back on the engine cover, started it up, cleared the fault codes with the vag-com and monitored both the interior guage and the ect reading in the engine readouts.