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Mike S.
Mike S., ASE Certified Technician
Category: GM
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Experience:  ASE Certified with 25+ years experience.
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2000 GMC Sierra 1500: my check engine light came..light stayed

Resolved Question:

I have a 2000 GMC Sierra 1500 5.3 litre engine. About two months ago my check engine light came on and  they checked the codes and they were po 137 and po 157. The light stayed on for about three weeks. And after three weeks the check engine light went off  with out me doing anything and when I took it back to get the OBD reading it came up with no codes. What do you think caused the check engine light to come on??? and go off and now show no reading (no problem)???
Submitted: 5 years ago.
Category: GM
Expert:  Mike S. replied 5 years ago.

WEll, the codes will clear themselves after so many warm-up cycles. I believe it's about 40, so it sounds like that is what happened.

Now about the codes P0137 and P0157.

P0137 refers to HO2S-12 (Bank 1 Sensor 2) Circuit Low Input.

P0157 refers to HO2S-22 (Bank 2 Sensor 2) Circuit Low Input.

If you want more info on those codes, click here. The codes are listed twice, once with RPO code OSG and one without. From what I gather RPO code OSG stands for the Plant Code, Oshawa, Ontario, GM of Canada.

If the truck is running fine now, I would just ignore it. If they come back you have the diagnostic procedures and some possible causes in that doc.

You could have had some water in the gas. That is about the only thing I see from the possible causes that may have cured itself.

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