P0402 Mercury - 2003 Grand Marquis

Question

I have a P0402 Check Engine light code. I can't find anything for a 2003, just up to
2002.

Would like to know what might cause this problem and where the parts are located
on the car.

Thanks,
Ken

Answer 1

Hi there,

This code indicates an issue with the EGR. Here is a list of possible causes.

P0402 MERCURY - Exhaust Gas Recirculation Flow Excessive Detected

Read more: https://www.autocodes.com/p0402_mercury.html