Q: PO402 Excessive gas recirculation code

asked by on March 05, 2017

I have a piece of exhaust flex pipe that's cracked and it's between the manifold and the catalytic converter. Would that cause check engine PO402 code?

My car has 122248 miles.
My car has an automatic transmission.

Hi there - while a cracked exhaust tube of any sort is a problem that needs to be addressed, I don’t think it’s related to your P0402 code. P0402 indicates excess exhaust flow into the intake - probably caused the EGR valve not closing properly, or a broken EGR valve spring. I recommend a rough running inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.

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Hello, thank you for writing in. The vehicle is likely experiencing an issue with low vacuum due to the exhaust leak. This low vacuum WILL cause the EGR system to malfunction. You should focus your attention on repairing the exhaust leak, and test to make sure the codes then go away once the computer has had time to reset. If the code does not go away at that point, you will want to look further into the EGR system and make sure it is not clogged with debris or buildup. If the problem continues after that, you may end up needing to replace the entire EGR system. For more help, contact our service department to schedule an appointment.

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