GM P0402 Engine Code

[badluck24/7]

2007 Silverado LBZ Duramax, P0402 - EGR A Flow Excessive Detected. Didn't find much on this code directly related to the Duramax but I read EGR and think $$. Get a CEL light when trying to get onto freeway at speed or throttling down to pass. No issues while city driving. Only under throttle. Can anyone point me in the right direction as far as anything I can check myself during this holiday weekend? Let me know if more info is needed.

 

[Havasu blue label]

Shit my traction light just kick on

 

[mjc]

2007 Silverado LBZ Duramax, P0402 - EGR A Flow Excessive Detected. Didn't find much on this code directly related to the Duramax but I read EGR and think $$. Get a CEL light when trying to get onto freeway at speed or throttling down to pass. No issues while city driving. Only under throttle. Can anyone point me in the right direction as far as anything I can check myself during this holiday weekend? Let me know if more info is needed.

Can you reset it and go on?

 

[badluck24/7]

Can you reset it and go on?

I can reset it and it’s fine until I have to give it “heavy” throttle them it comes back on like clockwork. Just trying to figure out if it’s something dumb like a dirty sensor, loose clamp, or worse like a serious EGR problem.

 

[monkeyswrench]

If it's stone stock, check all your V-clamp and other fittings. They can get to being loose, and effect ratios. If it's tuned, the the flow could be out of factory parameters. In both cases, there is an exhaust backpressure sensor deal...it can get carboned up, giving false readings.

Sorry, not any real help, but some places to look.

 

[TrojanDan]

I just had Robinson’s Automotive change out my FICM on Wednesday and the mechanic had to unplug the EGR sensor to install the FICM. After a few miles my LLY threw a P402 code and I went back to the shop. The mechanic unplugged the EGR sensor then reattached it and it’s been fine the last couple of days. Try unplugging it and plugging it back in. Hopefully it’s just a loose connection.

 

[SBMech]

EGR Valve is sticking. Take it off and clean it then check operation of it.