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rick-l rick-l is offline
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Join Date: May 2002
Location: St Louis
Posts: 4,211
Quote:
Originally Posted by RANDY P View Post
1st O2 sensor actually does feedback to CPU to adjust air fuel. 2nd o2 is there as differental to show the 1st one is working. Most don't change 2nd one till outright failure.

the 1st O2 has to cyclevoltage readings a certain amount of times and if it doesn't then it stores the code tenatively as pending, then eventually a failure. You reset the code it'll come back eventually.

rjp
The 1st O2 sensor is used to adjust fuel trim at cruise and idle. The 2nd O2 sensor is used to test the catalytic converters ability to store oxygen or how efficient it is.
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Rick
88 Cab
Old 06-03-2009, 08:45 AM
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