Hot engine temperature warning - P0118

Hi all I have a c3 Picasso 1.6hdi that currently is causing me headaches . Having issue of bad starting when cold and also engine temperature to high alarm comes up almost straight away . Then after a short time the anti pollution alarm flashes up . Diagnostics code of p0118 of which is not clearing . I've changed the ECT senor and still had the fault . Now had a vehicle electrician check all wiring and he said can't find any issues there . So my question is are there anymore engine temp switches I could change or is it worth changing the actual thermostat housing . Could it be the ECU it's self . Sorry I know its a lot of things but really need help . Not sure what other info I need to give Many thanks in advance .

Pjn4156 wrote: ↑Tue Nov 16, 2021 6:06 pm Hi all I have a c3 Picasso 1.6hdi that currently is causing me headaches . Having issue of bad starting when cold and also engine temperature to high alarm comes up almost straight away . Then after a short time the anti pollution alarm flashes up . Diagnostics code of p0118 of which is not clearing . I've changed the ECT senor and still had the fault . Now had a vehicle electrician check all wiring and he said can't find any issues there . So my question is are there anymore engine temp switches I could change or is it worth changing the actual thermostat housing . Could it be the ECU it's self . Sorry I know its a lot of things but really need help . Not sure what other info I need to give Many thanks in advance .

Hello Pjn4156

I would connect up lexia tool (available here) to monitor the live data from the Engine Coolant Temperature sensor.

The P0118 fault could be a bad earth, poor connection at the sensor or a failed ECT bad sensor. You have changed the sensor and had the wiring checked so that leaves the live data to look for constant or intermittent faults on the sensor which may help identify the cause.