what does the code 402 mean in pontiac grand am gt 2002

Asked by Nov 10, 2012 at 03:51 PM about the 2002 Pontiac Grand Am GT

Question type: Maintenance & Repair

I have changed both upstream and downstream o2 sensors and installed a new thermostat and then cleared the codes,, 2 days later service engine soon light light comes on with code 402...Could this be the catalytic converter ????    I hate to spend the cash if this is not it,, please help me if you can kevin k thankx

1 Answer


Let me guess auto zone told you that the code meant the O2 sensors were bad so they could sell you 2 $80 sensors? P0402 has nothing to do with a bad O2 sensor its caused by excessive egr flow and the link takes you to a site that will explain how to diagnose what exactly it is so you don't have to throw parts at it. http:// www.obd-codes.com/p0402 feel free to reply to this post if you need more help, I will get an email on my phone within 20 minutes of your reply and I will get to it once I have a few free minutes.

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