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Q: Code p0140 we replaced 02 sensor and catalatyic converter

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We replaced the catalatyic converter and the back 02 sensor and we checked the wiring for 12 v it's all good
My car has an automatic transmission.

A: The vehicle should have an original equipme...

The vehicle should have an original equipment HO2S not aftermarket generic. For a P0140 code, the wiring harness should be closely inspected for damage: chafing, pinches, melting, or water intrusion into connector. Exhaust leaks upstream of the HO2S must be eliminated as that can also cause this DTC. After all other possibilities have been eliminated, the PCM may turn out to be the root cause. An experienced mechanic performing scan tool diagnostics would be recommended at this point. A technician from YourMechanic can come to your home of office to thoroughly diagnose your Check Engine Light and make the correct repairs.

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