Volvo V70 1999 2.4 B5244S - MIL comes on when driven - gearbox replacedArchived Message
Posted by Nick Bell on August 31, 2004, 6:09 pm
Hi All, Puzzled about this one. Problem started after gearbox replaced (different garage) and another O2 sensor bush welded in place on exhaust?? EML light comes on after being driven, ignition off then back on after 5 minutes. AD Pro EODB shows O2 Readiness tests not complete etc.. Live data shows pre-cat O2 sens. @ about .45V almost permanently and post-cat @ 0.9V. Checked continuity of signal and return cables back to ECU. Both OK. Checked voltage @ sensor and return is about 3.5V and signal is 3.8V. Incidently this is confirmed by Autodata. I presume just the voltage difference between sig. and ret. need to be considered. The O2 sens. has, apparently, been replaced at the dealers recently so should be OK. Been back to Dealer several times They replaced AMM and now say needs ECU. Plugged old spare O2 sens. (possibly the original) into socket and monitored volts in live data while spraying sensor with carb. cleaner. Could get volts varying between 0V and 0.9V. Have decided either 'new' sensor faulty, or welded bush is not air tight and letting in air! Any comments about diagnosis or sensor voltages relative to battery -ve please. Garage are taking off exhaust to check sens. bush, and penetration into exhaust flow. Will be going back when this done. Regards, Nick Bell