I have an 07 GMC 2500 with the Duramax. 62000 Miles, bought it new.

Drove 200 miles in heavy rain Wednesday to the family's house for Christmas. Truck sat Thursday, wasn't ran. Friday morning, went out and started the truck and let it run for about 15 mins. Elevated Idle was on and was not plugged up. Went back out and shut the truck off. (Outside temp was about 30 degrees.) Few hours later, went back out and started the truck to take the family out. Again, not plugged up. Elevated idle was on. Ran for about 10 mins. Noticed that there was a surge now and then in the elevated idle, and it did not go off hi idle until I pressed the brake. Got in it, had a check engine light on. Truck ran fine with no obvious operational issues. Got back home and plugged it in.

Got up this morning, unplugged it, started it with no problems, check engine light was still on. Took it to Blackwell Baldwin GMC in Poplar Bluff, Missouri to see if they could at least check it out as I had 200 miles to drive back home. Codes showed EGR valve. (Sorry, I didn't write them down. Should have) Technician cleared the codes, checked a couple of things and told me I should be ok driving home. Dealership did not charge me for any of this. Drove home in 30 MPH headwind at 70-75 MPH. Truck ran flawlessly and the light did not come back on during normal operation.

Seems to me if I had a legit problem, that the light would have come back on over a 200 mile duration at 70-75 mph. What do you guys think? I have an appointment with my local GMC dealer Mon morn, but I have an 800 mile round trip to make early this week with the truck.

I had this same problem with very similar circumstances. I was out of town and had a dealer clear the codes. When I got back my local dealer they had to clear out the EGR valve because the Check engine light had come back on. I did the EGR plate right after that....Good luck!

I had this same problem with very similar circumstances. I was out of town and had a dealer clear the codes. When I got back my local dealer they had to clear out the EGR valve because the Check engine light had come back on. I did the EGR plate right after that....Good luck!

Could you or someone elaborate on the EGR plate?

Do a search on EGR Blocker plate and sit back, relax and read.

do the egr block...add fingerstick if required and Pho git about it. It will be one of the best mods you can do for your intake, pce of mind and your wallet.

stk

The EGR code is P0403. Mine went out at 30,000 miles. It took three trips to the dealer before they finally repaired it. GM's requirement is that they clear the DTC code and reprogram the ECM with a wider span for the EGR alarm. When it next fails they "clean" the EGR valve and clear the DTC code. Finally they replace the EGR valve. The mechanic may have adjusted your EGR setting, allowing the light to remain off for a time. I went two days before it returned. Mine was covered under the 100k DuraMax warranty with a $100 deductible. EGR valves are a consumable, like many of the other sensors, PCV valves and filters, except that the DuraMax costs $500 at the dealer.

As I understand it, the EGR valve has to be functional before you block it. Yours should be covered under warranty.

The dealer's mechanic assured me that operating the truck with the non-functioning EGR valve would not harm the engine.

I had the exact same thing happen on my 06 after letting it idle for an extended period once. The CEL came on and off several times over the next few days and then went off and never came back on. While it was on I had the code read at Autozone and I think it was the 0403 or something like that.

I plan to do the blocker plate at some point but in the meantime am not losing any sleep.

Hi everyone.. This is my first post, I usually just use the search button and learn learn learn. I have the same exact problem. 63k miles, LBZ, cold weather, plugged in, idling often, and now I am plowing snow with it. It has been below freezing for about 10 days in a row so the truck hasn't had a chance to thaw. I read somewhere the p0403 EGR code has something to do with cold weather. I had autozone clear my code today, but it came back on within 10 mins. Truck is in garage thawing now, I will get it cleared again and see if it helps any..

My father is getting the same code (p0403). We took it to the dealer and they replaced the EGR valve. We then blocked it and put the stick in. He has been getting the code off and on now for the past 4 months. He has taken it to the dealer and they are saying that it has something to do with the mas air sensor so they have replaced gaskets and even used special glue to seal the resonator on the top of the motor. He is still getting the light and code. Is there any way that the fingure stick is causing this code to come on. The last time it was at the dealer, he pick up the truck and blocker plate was on the floor mat, but they said nothing about it. We now have the blocker plate out with the stick in and he is still getting the code. From what I know the dealer has installed 2-EGR valves, 6-gaskets and sealed up the intake system with sealant. So I know that this code has nothing to do with the fingure stick but has anyone out there had problems with the stick causing this code? We are going to remove the stick next and take it back to the dealer to see if we can get this code to clear. O' his truck is an stock 2007 classic. The only mods were the plate and the stick. Let me know your thoughts.

That sounds frustrating. I thawed my truck out but the code came back again today. Going to the dealer tomorrow to find out what's going on with mine

My father is getting the same code (p0403). We took it to the dealer and they replaced the EGR valve. We then blocked it and put the stick in. He has been getting the code off and on now for the past 4 months. He has taken it to the dealer and they are saying that it has something to do with the mas air sensor so they have replaced gaskets and even used special glue to seal the resonator on the top of the motor. He is still getting the light and code. Is there any way that the fingure stick is causing this code to come on. The last time it was at the dealer, he pick up the truck and blocker plate was on the floor mat, but they said nothing about it. We now have the blocker plate out with the stick in and he is still getting the code. From what I know the dealer has installed 2-EGR valves, 6-gaskets and sealed up the intake system with sealant. So I know that this code has nothing to do with the fingure stick but has anyone out there had problems with the stick causing this code? We are going to remove the stick next and take it back to the dealer to see if we can get this code to clear. O' his truck is an stock 2007 classic. The only mods were the plate and the stick. Let me know your thoughts.
http://www.dieselplace.com/forum/showthread.php?t=274346&highlight=p0403 Post #2

I made a mistake in my post. The code we are getting is P0402 not the P0403. So anyone out there have a solution for this code and all the problems he is have in the previous post.

I made a mistake in my post. The code we are getting is P0402 not the P0403. So anyone out there have a solution for this code and all the problems he is have in the previous post.
Check the fittings on the intake from the filter to the turbo. Including the Resonator and the PCV hook this will trip the 402s. Does your dad have an aftermarket air intake? If so, put the stock one back on and see if that takes care of your P0402