3.0 Duramax P1488 CEL code

BillP89 · July 9, 2020

2nd day of owning this truck got this same code... I hope there is a fix and that driving with it isn’t so bad because my schedule is hectic and dealer is a little ways away.

Edited July 9, 2020 by BillP89

BillP89 · July 14, 2020

Any one have an update on this issue?

RockyBlue · July 29, 2020

Still working through this issue. Been to the dealer several times. They have a few 3.0 Duramax trucks that are experiencing the same thing. GM Engineering is now thinking it is a leak caused by a clamp. New clamp is on back order so I will bring the truck back in once the part is available. This back and forth is driving me crazy!

Colossus · July 31, 2020

What dealer are you working with

Desmo · August 22, 2020

My LM2 had this code, dealer performed a service on recall N202300791 to reflash the ECU or module that controls the DEF injection. They also replaced the failed sensor. I only have a few miles on the truck since this fix, hopefully the CEL stays away.

gearheadesw · August 26, 2020

Wow, so no diesel in my future. Only in America can we totally screw up a diesel.

BurnsMax · August 26, 2020

1 hour ago, gearheadesw said:

Wow, so no diesel in my future. Only in America can we totally screw up a diesel.

My LM2 has been solid with just a little over 5K on the clock. Had a TSB for the shifter but that would be with any Silverado. Gas mileage is great. Last trip I had 520 miles and 3 gallons left on the small 24 gallon tank. Diesel is only .05-.10 more in my area

Edited August 26, 2020 by BurnsMax
Added info

Ogee1 · August 26, 2020

Hey everybody, just wanted to update my experience with the P 1488 code. So after 7 trips to the dealership to fix this issue, I was given a letter from “GM senior engineer “ that there would be a recalibration done in September. Well this was back in late May and I had had enough of the issue, so I filed a buyback/ repurchase request. I really like the trucks performance and MPG. GM bought back my truck and I got an almost identical truck in return. It took almost two and a half months, but it finally got done. I got an almost identical truck thinking that the issue was very limited and wouldn’t have to deal with it again.

Well guess what? My second truck has this same damn code. I thought that I would be done with the issue, but now I have to wait until next month to see what this recalibration is going to do. I will keep everyone posted as to what happens with this so called recalibration.

Hey Rockyblue, the clamp issue you posted is the first I’ve heard. Please keep us updated if the repair works or not. Thanks

steve841 · August 26, 2020

12 minutes ago, Ogee1 said:

Hey everybody, just wanted to update my experience with the P 1488 code. So after 7 trips to the dealership to fix this issue, I was given a letter from “GM senior engineer “ that there would be a recalibration done in September. Well this was back in late May and I had had enough of the issue, so I filed a buyback/ repurchase request. I really like the trucks performance and MPG. GM bought back my truck and I got an almost identical truck in return. It took almost two and a half months, but it finally got done. I got an almost identical truck thinking that the issue was very limited and wouldn’t have to deal with it again.

Well guess what? My second truck has this same damn code. I thought that I would be done with the issue, but now I have to wait until next month to see what this recalibration is going to do. I will keep everyone posted as to what happens with this so called recalibration.

Hey Rockyblue, the clamp issue you posted is the first I’ve heard. Please keep us updated if the repair works or not. Thanks

Definitely update us! Thanks

gearheadesw · August 27, 2020

On 8/25/2020 at 9:52 PM, BurnsMax said:

My LM2 has been solid with just a little over 5K on the clock. Had a TSB for the shifter but that would be with any Silverado. Gas mileage is great. Last trip I had 520 miles and 3 gallons left on the small 24 gallon tank. Diesel is only .05-.10 more in my area

There's no denying that modern day diesels have serious problems. Just check this thread, yours might not, but it's very, VERY common, from one ton trucks down.

Colossus · August 28, 2020

One ton trucks? Hell it's with the big rigs too! The emissions stuff really screwed things up.

RockyBlue · September 3, 2020

Sorry been so long since I have posted here. Still wrestling with this. My dealer is Ed Bozarth Chevy in Colorado. I am in the same dealership as another owner who had his in the shop for over a month and Chevy bought back the truck. Mine is up next. The clamp issue didn't turn up anything. GM engineering shipped out a whole new exhaust assembly for the other truck owner but that didn't work either. I like the performance on the truck but don't think I can pass emissions with an engine code. Not to mention the possibility of going into Limp Mode which I've heard can happen.

Colossus · September 4, 2020

Down at Park Meadows? That is my neck of the woods. They always treated me well every time I had to deal with them.

yousaveone · September 4, 2020

Ed Bozarth is pretty good. My engine is great but truck has weird infotainment quirks and climate control issues. No matter how good the dealer is they only can do with the provided FSBs or TSBs to do. This is a bad on GM, and the USA in general. ALL PARTS need to be made and assembled in the USA; I'd pay more for that.

RockyBlue · September 6, 2020

On 9/3/2020 at 10:07 PM, Colossus said:

Down at Park Meadows? That is my neck of the woods. They always treated me well every time I had to deal with them.

Yes that is the one. I will be taking my truck to them next week to start the process. 30 days in the shop for them to try and fix. Then start the buy back process.