02 sensor

[HELLBENT93]

does the code 172(HEGO shows system always lean, rear) for the o2 sensor mean the sensor is bad or is it that it just knows the mixture isn't right, if so why would cause it to read lean? Could insufficient egr flow do this?

 

[sdpatt]

The 172 code reveals that the rear bank O2 sensor was not switching from the lean reading. If both sensors were showing lean, then I would suspect an engine control problem that was creating a true lean condition. Since only one sensor had the problem, this most likely indicates that the sensor has retired and should be replaced. Since both sensors have probably been installed the same length of time, this would probably be a good time to replace both of them. The O2 sensors should be replaced at the same interval as the spark plugs because they also get tired and are unable to switch from rich to lean quickly enough to keep the engine at the optimum mixture. This will penalize you be creating higher emissions output and higher fuel consumption.

You should check out AutoZone for the Bosch 13223 (or 15716) with 8.5" leads for $49.00.

 

[Machspeed]

sdpatt:
The 172 code reveals that the rear bank O2 sensor was not switching from the lean reading. If both sensors were showing lean, then I would suspect an engine control problem that was creating a true lean condition. Since only one sensor had the problem, this most likely indicates that the sensor has retired and should be replaced. Since both sensors have probably been installed the same length of time, this would probably be a good time to replace both of them. The O2 sensors should be replaced at the same interval as the spark plugs because they also get tired and are unable to switch from rich to lean quickly enough to keep the engine at the optimum mixture. This will penalize you be creating higher emissions output and higher fuel consumption.

You should check out AutoZone for the Bosch 13223 (or 15716) with 8.5" leads for $49.00.

ya...thats what i was gonna say...