carlzday

06 avalanche Z 71...the vehicle was serviced today, and diagnosed by a reputable garage ..they replaced the S1B1 O2 sensor, they cleared the code, they drove it while on their " $60,000 ", diagnostics machine for 15 mins .and, all was good with all O2 sensors working within spec and no further codes ...the check engine light was finally off ..... I drove it home, a total of maybe 5-6 km ..still no light when the vehicle was shut off.

Then...6 hours after getting it from the garage, as soon as the engine was turned on, the service engine light, reappears ... I then drove it maybe 10 more km ...let it run while I was in the store and the light still continues to stay on. (it should be noted that the temp outside was about -15C (7F)--if that matters ) does this sometimes happen...I've read a few other forums where they stated that their codes had to be cleared up to 3 times before it stayed off