ok i am not too familiar with the car codes but if there was a bad sensor wouldnèt the check engine light come on.I mean when my maf sensor was bad the light sure did come on bright and as orange as ever but someone told me that you can have a bad sensor and the light not come on anyone who anythin about this stuff please reply as soon as possible.

 

That's true, you could have a bad sensor that give eroneous information, but is still within the parameters the ECM is expecting to see.

FYI, just be cause a code sets, does not mean that particular sensor is bad, but most likely that what that particular sensor is sensing, is not correct. Make sense?

 

Meaning a "high voltage at CTS" code 15 could mean that the sensor 'thought' the voltage was high because the sensor was hosed ? Even though the voltage might be normal ? Meaning 'high voltage at cts' might be set even though the voltage was normal or maybe even low ?
The mind reels......



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88 GTA Charcoal Grey Bone Stock except for loose muffler which makes it a bit louder than normal.

 

I guess a better explanation on my part (re-reading my post even confused me) would be like:

code 44 O2 sensor detects lean exhaust.

Could be a bad O2 sensor, sure, but more than likely the O2 sensor is doing it's job as designed to do, and there is not enough fuel in the A/F mixture...caused by some other part of the fuel system being at fault.


Now lokk at a bad O2 sensor, reporting "good" info to the ECM..

O2 sensor is fouled, which skews it's readings. Car runs rich (due to in this example a bad O2 sensor) but it's output voltage is within the 100-900mvs expected by the ECM and has the required crosscounts to make it seem like it's operating normally.

[This message has been edited by 8Mike9 (edited July 18, 2001).]