Planning the next
AO Silver Member
Join Date: May 2007
Location: United Kingdom
You probably have the ME2.1 ECU and the 15A fuse with Red/Black & Red/Black is probably fuse S45.
S45 powers :
Evaporation solenoid valve
Air flow meter
Cam angle sensor
So that has narrowed things down a bit.
You could now work on a process of elimination.
e.g. disconnect one lambda probe and see if the problem goes away. From your original description, it seems that it fails reliably (?) so once you have a level of confidence that one component is OK, move on to the next.
One caveat : I don't know if the ME2.1 will reset the ECU warning light automatically when a fault goes away. If not, do you have access to a device to reset fault codes?
My hunch is that this may be related to the heater within one of the lambda probes.
I don't know if the V6 will run without the cam angle sensor connected. Can anyone else advise? I'd leave it until last anyway.
If it isn't any of those components, it could also be a short from maybe frayed wiring somewhere in the loom. You could check for that visually and with the multimeter :
Remove the fuse
Put the multimeter on DC volts and switch the ignition to MAR. Establish which side of the fuse holder is +12v.
Switch off the ignition.
Change the multimeter to continuity
Check continuity between the other fuse holder terminal and earth whilst moving the engine loom around.