Here is some information from another forum that might help. Not sure it's the same issue or not.

http://www.duramaxforum.com/forum/2011-lml-duramax-powertrain/536146-egr-cooler-bypass-valve-gm-letter.html


There are lots of threads from various forums on this if you do a general Google search.


Good luck!

 

The best (easiest way) to do the repair is to pull the cab. GM instructions tell you pull the transmission. If you have the patience it might be possible to do this repair without doing either. If I had to try one in my driveway I'd try to jack up the right side of the cab, unbolt mounts along that side, loosen left side and lift right side with a couple floor jacks.

If you are not afraid of some hard work, that would be the way I'd recommend. If you do try to tackle it, feel free to ask questions, I myself am a GM tech, and I think there's a couple others that float around these forums.

 

FWIW, Alldatadiy says it's 3.0 hours to replace the EGR valve, $323.58 for the EGR valve, dealer list. Additionally, they say 3.1 hours to replace the EGR cooler (EGR valve is attached to the cooler), so maybe 6 hours to pull the cooler and valve, replace the valve on the cooler, and reassemble. This would be for a 2008 2WD. I wouldn't think yours would be drastically different.

 

An EGR valve is a totally different animal than an EGR cooler bypass valve.

On a LML engine, the EGR valve is near the front on the left side, it has a brown connector with a yellow retainer. The cooler bypass valve is at the rear of the passenger side, almost can't see it below the cowell, but has the same style connector plugged into it. The rate for the bypass valve is near 10 hours I think. Don't have access to labor times on my iPhone.

To replace EGR cooler(s) on a LML is very different too, there's two. Two halves anyway, one along the right side, joins to one across the top/front of the engine. Rear one is a bear, front one not too bad.

A 2008 has a lot less junk (err emissions components) in the way!

 

To replace EGR cooler(s) on a LML is very different too, there's two. Two halves anyway, one along the right side, joins to one across the top/front of the engine. Rear one is a bear, front one not too bad.

Thanks for the information, this is helpful.

So are there (2) EGR cooler units and (1) EGR bypass valve that need to be bought? If it is reading failed bypass will I be able to replace the (1) component and be done or is it a best practice to replace all these parts while you're in there. I know I won't want to do this twice.

 

There is no reason to replace a cooler that is not faulty. You only need the actual valve, on the part diagram you supplied it is call out #3. You will also need gaskets 14, 18, 29, and 39. If you attempt without removing the can you may need more gaskets/seals.

The most difficult part of the job will be removing bolts #15 in the diagram, they are accessed from the back side.

 

Thanks again for getting me in the right direction. Taking a look at the cab, looks like (6) bolts. Do I need to worry about any wiring harness snag or is there enough slack built into the one at the firewall?

Also, on a separate note, is driving around with a bad unit going to do any damage? I don't put a lot of miles on it but was going to take the truck up and down the coast possibly a few hundred miles but not sure if this unit (if stuck open) will cause any major failures in the engine.

Thanks again guys.

 

I don't think I'd worry about the codes while driving, they are not codes that cause reduced power and the only difference between the cooler bypass valve being operational or not is the tempature of the EGR gasses. It's still going to recirculate the gasses, just might not be the tempature that the ECM wants them to be.

There is 4 bolts per side of the cab on a crew cab, 3 behind the front wheels and one in front. The one in front is from above but the threaded end of the bolt has a hexed end so you can turn out out of the nut. Hold the nut and turn the bolt out of the nut.

Don't lift the cab any more than a few inches on the right side to prevent straining any components. There are lots of things that could be damaged if it's lifted too far without disconnecting anything. Remember to leave the bolts in on the left side, just loosen a couple turns, you'd hate yourself if they were removed and something happened to shift on you. I've never actually done this, just going by experience working with these trucks, so be mindful of things that might be pulled/stretched while jacking up the side of the cab.

 

So my 2011 GMC has 82,000, check engine light came on, showed the p140a and p2493 codes, checked and reset, came on again later in the day. From above post appears it should be ok to drive, have not noticed any issues so far today. Taking a 600 mile trip end of the week towing 5th wheel. Doubt our sorry dealers here could have it fixed by then if they will even do it.
Question-OK to make the trip and worry about when I get back?
Pete

 

Your truck should be fine to drive, as long as those are the only codes stored. As long as you don't mind the CEL.

 

For what it's worth have your dealer look into your VIN and see if you are covered by the special policy they put in place for those trucks. I don't remember what years and models were involved but there was a good chunk of trucks that were covered by it, they are usually covered for something like 10years/180k or something. Always good for when you're outside of warranty.

 

I have mine in the shop as we speak and was told that they warranty for the P140A was 120K. I have 125k when I dropped it off, it will be interesting to see what happens. I have had it there almost a week now and was told it could be two weeks before they even look at it.

I might be deleting for sure now. Not expecting good news.

 

I'm having the same issue p104a and p2493. 2011 GMC Sierra 2500. Is there a way to check if my VIN is covered under the extended warranty?

 

GM will cover repairs up to 10 yrs or 120000 miles.
I know you make one criteria. Most likely your not the original owner. Then they can look up when put in service by vin. But your not close to 2021 if your over 120k your SOL
http://www.duramaxforum.com/forum/attachment.php?attachmentid=545122&stc=1&d=1416689105

 

I'm the original owner. I've never received a letter like this one. I got one for something about the DEF and the sensors for it that was 10yrs/120k miles. I saw something about being only the 3500? How is that possible when it's the same motor and drivetrain?