'ello all,

Strange one here, intermittently I get a CEL. The code that then shows up is rear 02 sensor open circuit (or something like that ). When stationary it shows up as 0v and then varies when in motion to around 0.8v. There doesn't appear to be a difference in the readings when the CEL is on and when it's off. The light turns off on it's own i.e. I don't reset the ECU. Any ideas? Dealer can't explain it.

 

Same thing was happening with my UK MY00 (CEL coming on and fault code pointing to rear 02 sensor). With the diags connected I could see that the voltage intermittently dropped to 0v, which it shouldn't do apparently, which suggested a faulty sensor. Had it replaced on warranty and it's been fine ever since.

 

Strange thing is that this is a brand new sensor.

 

could be the wiring that the sensor plugs on to?

 

Dealer says it seems fine, CEL has been off for 2 days now after being on for 2, after being off for 1 after being on for 4, etc.