2016 -Low Power Mode Service Engine Light

trpshoot · October 15, 2017

Last week after towing my 12K fifth wheel to Florida, I was in a parking garage and had to make a four point or so turn to get it of the garage, after driving down the block and the tranny shifting to third, the RPM's sky rocket and then there was a loud clunk into fourth gear. This went on a couple more times and I pulled over, and started and stopped the ignitijon maybe 3-4 times. I had zero issues the rest of the week that I was not towing and just driving. Yesterday after towing about 450 miles, I get a steady yellow engine light that comes on and the display "reduced power" or a message similar to that. The freaking truck wouldn't let me go over 10 mph while towing the camper on a stretch of interstate that does not have a full shoulder. So after successfully not getting rear-ended on the interstate, i make it to an exit My engine temp is fine, no other issues. I shut the truck off, wait 10 minutes or so and cycle the ignition, the LOW POWER/REDUCED POWER message disappeared however the yellow engine light stays and is on steady. I successfully tow the trailer home the last 40 miles without issue, power seems normal, etc. After getting home, I disconnected both positive and negative cables from each battery and waited about 5 minutes and reconnected. Light is still on... So I have just over 12,000 miles on this truck now. I am going to schedule an appointment with the dealer, what are your thoughts?

Did the shifting incident have anything to do with the temporary loss of power issue yesterday? A bad sensor in the tranny, two bad sensors?

8lugCT · October 15, 2017

No answer, but I'm subbing to find out

redwngr · October 15, 2017

If it was mine, I'd take it in to both find out what the issue is and get it documented.

trpshoot · October 15, 2017

Dropping off at the dealer on Tuesday... Funny thing is that I didn't mention the other problems that were 100% my fault. At one point the fifth wheel trailer plug came partially unplugged which created a STABIL TRACK, SERVICE TRAILER, and ABS light to come on; after reading the manual that was quickly fixed by cycling the ignition a few times. A couple days later I evidently didn't get an actual positive click on the fuel cap, so I got another light... again, clicking the fuel cap like I have done for over a year and then cycling the ignition made that light go away... my young one last year when we picked up the truck named the truck the Millennium Falcon... the wife and I have renamed it the "MILLENNIAL FALCON." This is a ridiculously delicate snow flake of a truck...

TRKLGND · October 16, 2017

So... if the issues were 100% your fault, how is the truck a snow flake?

trpshoot · October 17, 2017

20 hours ago, paracutin said:

So... if the issues were 100% your fault, how is the truck a snow flake?

Two out of four issues were my fault, however when coupled with the other two issues serious issues we decided to make light of the all the overall travel incidents. So... it is a joke.

trpshoot · October 18, 2017

So the two issues that were not my fault... can not be figured out by the dealer who says they consulted with GM tech support.

INCIDENT: #1 Since a code was not thrown last week with transmission shifting issue, the dealer and GM tech support can not find a reason for the failure to shift into 4th gear. GM tech support can not explain why cycling the ignition a few times resolved the issue.

INCIDENT: # 2 The GM tech read the Global Diagnostic System 2 (GDS2) / Freeze Frame/Failure Records and can not see any reason for the truck going into REDUCED POWER / LIMP MODE. They can not replicate the trouble code, the code is generic and all diagnostic checks come back normal.

The dealer verified that all computer programming is up-to-date and then reset the computer to erase the engine light/ trouble code..

So no longer a joke, this so called Heavy Duty Diesel is a snowflake. I hugged it and told it that it was special before starting and driving home; no error codes so far... I told it that even though it sets in an insulated garage... I am going to put a blanket over the hood and keep it plugged in if the ambient temperature gets below 70 degrees.

8lugCT · October 18, 2017

Make sure to wipe the exhaust soot dribble from the tail pipe

trpshoot · October 19, 2017

Here are the codes that I found hand written on the work order:

P0234

P2599

P2263
P262B

I searched these codes and see that some have to do with the turbo and it says the turbo should be removed and inspected... I know that nothing was physically removed from the truck, so maybe I need to take to a different dealer? I won't be any more towing until probably May 2018, so do I wait that long and see if another code gets thrown?

So much junk on the internet, I don't what to believe about the codes. One post says the whichever code has to deal with the infamous assisted power steering; another one talks about shifting issues.

trpshoot · October 20, 2017

On 10/18/2017 at 8:23 PM, trpshoot said:

Here are the codes that I found hand written on the work order:

P0234

P2599

P2263
P262B

I searched these codes and see that some have to do with the turbo and it says the turbo should be removed and inspected... I know that nothing was physically removed from the truck, so maybe I need to take to a different dealer? I won't be any more towing until probably May 2018, so do I wait that long and see if another code gets thrown?

So much junk on the internet, I don't what to believe about the codes. One post says the whichever code has to deal with the infamous assisted power steering; another one talks about shifting issues.

What are the thoughts about these codes, is there a probable issue that needs to be corrected which warrants a trip to a different dealer, or do i just wait to see if it happens again?

cire0309 · October 20, 2017

http://www.dieselplace.com/forum/63-gm-diesel-engines/365-duramax-fifth-generation-2011-2016-lml/904225-p0234-p2263-p2599-towing-up-hill.html

Sounds like 3 of 4 are related to the turbo. Go find the service manager, ask them about these handwritten codes and what they did to troubleshoot your truck other than just clearing the codes.

Colossus · October 21, 2017

"Can not duplicate the problem" is what the response will be and they won't do anything until they can duplicate the problem. That is how they are now trained.

Downhill Duramax · November 30, 2017

My 2015 has dropped into "reduced engine power" mode 3 times all at highway speeds. Had plenty of def all 3 times and all 3 times it was related to emission control codes. How is this not flagged as a NTHSB safety issue. Without warning the vehicle drops from 70mph to 10 or 20mph. GM knows they have issue. I wish their Cracker Jack engineers could experience "reduced engine power" on crowed interstate hwy with their own kids in the car. It's sad when the only viable solution to make the vehicle dependable & safe is to decommission the emission controls. Now I understand why people were willing to pay premium on my 2004 (no def) Duramax.

avalonandl · December 7, 2017

Make sure you have good tight battery connections. I know this seems silly but an interuppted battery signal will cause the dreaded issue. disconnect all the batteries and check for corrosion on terminals.