207 1.6 VTi thermostat

[PopPops]

Hello, I hope this topic hasn't been covered before, but I could find no reference.

My wife's 10 plate 207 Automatic (genuine 12k miles and in immaculate condition) with the 1.6 VTi engine has just flagged an "engine management system faulty" problem. This happens immediately from start-up. We are in France at present and the only clues to the problem are that the temperature gauge varies wildly (coolant OK and no overheating) and the aircon doesn't work. I guess the ECU has switched off the aircon due to the fault. The car's performance seems unaffected and the autobox changes exactly as before. The registered mpg seems as expected too.

I have done some initial diagnosing. The temperature sensor seems OK. It read about 3k Ohms when cold and when substituting a 1k resistor the temperature gauge read around 65C, and the resistance of the sensor gradually reduced as the engine warmed, so all seems OK there.

The top hose seemed to be warm long before the engine reached 90C but the bottom hose remained cold. When driving, the gauge never exceeds the normal 90C but rapidly drops below 70C going downhill say, and seems to settle around 80C at a steady speed.

I don't have access to a code reader here, but my guess is that the thermostat is faulty. Am I correct in thinking that this engine uses an electronic thermostat? I have removed the other black connector on the housing and get an almost open circuit reading of whatever's connected to it in the housing, I assume the thermostat "motor".

Is there any way of getting the fault code without a reader?

Am I on the right track, and if so, has anyone experience of changing the housing?

Many thanks, I'm sorry this post is so long, but I was trying to get all the relevant information down.

Nigel.

[Gibbo_Wirral]

Check the Lexia owners thread, there might be someone nearby with Planet.