code PO403 does anyone know?

[360duramax]

I have a 2007 GMC classic crew cdab and my check engine light came on, took it to the dealr and they said it was a PO403, which is an evap code so they say they cleared it, i drove off and 30 miles later the light came back on,
back to the dealer- this time they looked and an update needed to be downloaded from GM, drove off and 30-60 mile later light came back on

I have an appointment Monday the 8th for them to look further

Now a little history, i fueld up and drove off for about a mile with out the fule cap on, and it was snowing like crazy

Anyone have any idea's??

[Duramaster]

:confused: P0403 is an EGR code. I take it you are driving a 2007 Sierra Classic with a DMAX LBZ engine. :confused: No EVAP codes for the DMAX application. Anyway, if the ECM has the latest calibration in it the next step is to replace the EGR Motor itself. If your technician has any questions, give him this bulletin number........... 06-06-04-066A It's all about the EGR motor operation or lack thereof. :cool:

[360duramax]

Fantastic! this is why i love this forum. I witll make mention of that when i take the ol'Gal in for repair

[larryh1]

360, I just had the same code, 4/12, took it to the dealer and they stated just what Duramaster states. The motor was bad in my egr valve, tech said it was sticking. Don't know what that means concerning the egr valve, but it fixed it. There were also some PCM (?) udates installed. Any idea what those are Duramaster. I asked the service manager he said it could be a lot of different things that update the trucks computer.


Larry

[rickster58]

I also have a 2007 GMC Sierra Classic Crew Cab (Dually) with DMAX LBZ engine. Have been receiving PO401 and PO403 DTC's after installing K&N Air Charger and 4" free-flow exhaust. Can this be causing the problem, or is there really a problem with the engine that needs to be addressed by the dealer? Please advise.