Remembering why I
dislike working on
AO Silver Member
Join Date: Sep 2001
Re: Alfadiag tells me of a lambda fault.
That looks what I'd expect for a working probe - output drops to zero when the fuel is cut off on overrun, otherwise it dances around 0.6V - 0.7V or so which is where you'd ecpect it to be. It looks to respond quickly too, which is a sign it's healthy. An aging or poluted probe can be very sluggish to respond to changes in O2 content. More likely is a simple connection problem.
Quick way you can test the heater - do that logging process again from cold - you should see the lambda voltage start low (probably!), then fairly rapidly rise to a nominal 0.7V By fairly rapidly, I mean a few seconds - say 10 to 15 tops. This does assume you are seeing true probe volts, not a processed reading. It's possible the ECU might substitute a default value when the probe is cold.
One symptom of a faulty heater circuit is getting a lambda out of range fault under low speed/light load conditions.
Last edited by ChrisS; 18-07-08 at 14:09.