G62 - signal too low - intermittent. NOT the sensor.

On my daughters Octavia III 2016 there's an intermittent fault on the G62 sensor (coolant temp sensor, 1.6TDI, CXXB engine, 4x4).

Most of the time it works ok, but suddenly i reads +140°C (i.e. sensor wire short to ground, R=0Ohm, I think) and a DTC is saved in the memory. The sensor has been replaced without any difference. It happens once each second day or so, and the DTC also triggers the Engine Lamp. Sometimes it can be a little bit more often, and sometimes the temperature gauge may change from the normal 90°C position when this happens,

I read on an Audi forum about someone with the same problem that found an insulation issue on one wire in a harness where routed through the firewall/metal. When this wire was short to the metal the G62 error (140°C) appeared....

Anyone that have had this intermittent G62 failure on an Octavia III, and may have a hint of a common location for such insulation problem - if it's relevant ?

Edited 19 August, 20241 yr by Ingper