Hi guys bit lost with this one?
Car sat for 6 months after an issue with the Air suspension compressor (now converted to coil spring) there are no driving issues or warning lights on dash. The car failed the Mot with rather high results. Wanted to be sure with this as the Cat is over £400!
Firstly code read which showed two reocurring faults as follows-
B7 Idle Contact Signal Improbable
30 Oxygen sensor heating Open Circuit/Positive
Short
Cleared but both soon returned. Scoped sensor to find the signal stuck at 1.2v? even introducing an air leak only got the signal down to about 0.6v and took a while to get there! Checked heater Voltage which is present when sensor disconnected but goes to 0v when connected, (I dont have pcm pin data to check back at control unit) Changed sensor due to slow switching but no change and same faults still log? Checked injection period which at idle is 2.4ms on all four cylinders (scoped). Am i overthinking this one when it just needs a new cat? Is It possible that the suspension compressor has damaged the pcm as when it came to me the fuse had been bridged by the RAC and was momentarily pulling 60amps when ceasing!! If i have missed an obvious test please enlighten me Emmissions are as follows( Thankyou and sorry for long post)
CO idle- 3.600-4.150 cruise- 5.800
C02 idle- 12.09% cruise- 11.24%
HC idle- 266 ppm cruise- 183 ppm
LAmbda idle- 0.887 cruise- 0.835
02 idle- 0.38% cruise- 0.08%