Basically the Activa is showing the orange ECU light for alot of the time. It comes on when idling for a while, or if the engine is hot ie town driving.
It doesn't show when the car is cold, so first thing in the morning or on the drive home from work having been sat up for a while. But should I stop mid journey in either of these cases, turn it off for a minute then start it again the light will illuminate.
The problem with the light being on is that the fuel consumption is dreadful! It also means if I increase the boost, it will limit it while the light is on, which isn't fun.
I had the car plugged in to a diagnostic machine which said the fault was the ACAV valve. I've never heard of that, but going on the Citroen PR-net lookup it brought up the following diagram: (sorry about size)
The only two related sensors there are number 15 (Idle control valve) and number 20 (Reheating unit).
The car idles fine most of the time. Very occasionally it struggles to idle when re started hot but otherwise good. If you unplug the ICV when running the revs rise and fall back into place when replugged....whether the light is on or not.
The interesting thing is that mid journey while the light was on, I stopped and unplugged the reheating thing (don't know what it actually does) and the light dissapeared! Only did it that one time however, possibly a coincedence?
But with the ICV being expensive and the reheating thing not, I took the plunge and bought a reheating unit. Plugged it in, reset boost, unplugged battery for 15mins and tried it. Light was out, but came on again later having let the car idle, which it was doing no problem.
The Citroen dealer said there is a common fault on this engine with the plastic boost pipe that goes to the ECU, but I'm not convinced yet.
Anyone else have any knowledge on this subject? Any ideas gratefully recieved!
Cheers
