Today I put on a hardpipe from the turbo to intercooler. Then when i started the car the check engine light came on. Checked the code and it said code #21 (bad O2 sensor). I have a NB a/f ratio gauge that still seems to be working fine. I checked all the connections and the light still stays on. Is my O2 sensor actually bad? Or maybe a bad connection? maybe on one of the heater wires?
O2 sensor bad?
- Thread starter 1992supraman
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