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Q: How to fix or figure out exhaust system leak code P0402

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The engine EGR system may have exhaust leaks at the back pressure transducer

My car has 133500 miles.
My car has an automatic transmission.

A: Hi there. The code you have denotes excessi...

Hi there. The code you have denotes excessive EGR flow detected, not exhaust leaks. Anything on the EGR system could be causing this - a stuck open EGR valve, a stuck open switching valve/transducer, debris caught in the EGR diaphragm. Performing tests on this system should be performed by a qualified technician to ensure a proper diagnosis of the system and prevent the return of a Check Engine Light or drivability concerns. YourMechanic has several available technicians that can assist you with a Check Engine Light diagnostic if you would like to have an expert pinpoint the problem and guide you through repairs on site.

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