What is your question?
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What is your question?
PO503 Could you give me an estimate to replace the wiring harness. Could be a short circuit maybe. Thanks.

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The P0503 code is for the speed sensor, so I'm not sure why the O2 sensors were replaced. Not sure about the wiring harness cost, but I would pay a qualified tech to diagnose this issue to determine what is wrong. I wouldn't replace the wiring harness before having it looked at, otherwise you risk wasting more cash.
I have taken it to a GM authorized dealer who kept it two days and still could not tell me why the light keeps coming on to the tune of $700. for this one trip. Thanks for your help.
I took my car to another GM dealer in Nashville and they wanted to replace the transmission in my car. The transmission does not seem to be a problem. Do you have any other suggestions