ECT sensor issues in VW

[wokcz]

I have a VW Fox that is having issued with the engine coolant temperature (ECT) sensor. MIL was on, so I plugged ELM327 and it showed DTC P0118 (Engine Coolant Temperature Sensor Circuit High Input).

I removed the sensor, it has 4 pins, so it seems it has two sensors (one for ECU and one for dash) I tested the resistance of the two sensors with a multimeter with the sensor in cold and hot water, and got what seemed to be correct values (don't remember the readings right now but it was similar to what the manual said it should be). Then cleaned all the contacts and pluged it back in, cleared the DTC. After using the car for a few days, MIL is on again, same fault.

This time I checked freeze frame data, and coolant temperature shows -40C (lowest on the range the sensor can read, -40/150). Cleared the fault again to check freeze frame data once again when the fault appears, and coolant temp is always -40C at the time of the fault. The thing is, when I plug in the scanner, and check coolant temperature, is always a normal value, never something weird like -40C.

So my question is, could a faulty sensor cause this intermittent bad reading (always -40C at the moment the fault occurs), or is the problem more likely to be somewhere else?

[builes13002]

You want to remove DTC problme . You post your dimp

Envoy? de mon SM-J500H en utilisant Tapatalk

[wokcz]

You want to remove DTC problme . You post your dimp

Envoy? de mon SM-J500H en utilisant Tapatalk

What are you talking about? If I wanted to remove a DTC I would post in the appropiated section. What I am asking is if a faulty ECT sensor can cause this type of intermittent bad reading (-40C) or if I should be looking somewhere else to solve the issue.

[autoden]

Start with a new sensor. But get one from original, as aftermarket ones give trouble. Then you can recheck the readings. These do go down regular so I always start there.

[Nuz18t]

i would folow Autoden advice, if problem come back check plug/wiring!
Cheers

[wokcz]

Just fixed it a few hours ago. Sensor was ok, and cables were ok, it was this connector:

wxNoqMo.jpg

Replaced it and after like 12 driving cycles, no errors. The fault used to show up on the 2nd or 3rd cycle before.

[autoden]

Good work
, always nice to get a fix