Adam K

Lately my defi exhaust gauge have been erratic, I have gotten a fault indicating 'exhaust sensor ground short' when ignition is on but engine is not.
When running engine I can't tell if values are wrong, but when I wash windows or turn off main beams the value goes negative or through the roof!

I have disconnected the wire and checked that it isn't broken or chafed from the firewall to control unit. At the very sensor I can imagine that the wire is chafed, but how could switching window wash or main beam change anything there?
No other sensors behave like this, is it possible to be a problem with any other wires or power supply to the Defi control unit anyway?

audioscape

have you tried putting a multi meter across the power supply cables to see if there are any variations? when you operate the main beam or window washers.
what is the resistance on the ground wire to chasis. should be less than 1 ohm
what cable are you using as the supply to the gauges is it the ignition live to the stereo or have you run a seperate ignition live from the fuse box

Adam K

Yeah, thanks for telling me the obvious
Got my hands dirty (not really, couldn't bother to hoist the car to get to the sensor itself) and both wires on the exhaust sensors had 'something else than 1 ohm' But 1 ohm across themselves... No other sensor wires had anything but 1 ohm to vehicle ground.
Just to bite the dust and order another exhaust sensor, eh...