Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!
1 - 13 of 13 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
Just got a gmc 2500. I’ve had it for a week it has 150 miles on it now and after taking a 20 minute ride down the interstate I got an engine power reduced message, the engine light came on and the truck would barley move. Taking it to the dealer tomorrow. Has anyone had this problem with a new L5P?
 

·
Premium Member
Joined
·
5,057 Posts
nobody here can help you unless you know what code it is throwing.
 

·
Registered
Joined
·
218 Posts
Without knowing the code, my first guess is that the dealer didn’t fill up the DEF when you bought it. If that is the case, you should have gotten some warning messages on the dash letting you know that engine power will be reduced in X number of miles.

Like I said, just a guess since it is a brand new truck and you didn’t post the codes.
 

·
Registered
Joined
·
6,772 Posts
Low def goes to reduced speed limit, not to reduced power.

Even if it was empty, the first reduced speed limit is to 65 mph, after 500 miles. It runs a countdown screen that cannot be dismissed during the 500 miles.


If it was under 300 miles til DEF empty (and it only has 150 miles total on truck) it would have been giving 'miles to empty' warnings every time it was started.



At only 150 miles on new truck -- my money is on a faulty sensor or loose connector somewhere
 
  • Like
Reactions: 2ndwindranch

·
Registered
Joined
·
4 Posts
Discussion Starter · #5 ·
Low def goes to reduced speed limit, not to reduced power.

Even if it was empty, the first reduced speed limit is to 65 mph, after 500 miles. It runs a countdown screen that cannot be dismissed during the 500 miles.


If it was under 300 miles til DEF empty (and it only has 150 miles total on truck) it would have been giving 'miles to empty' warnings every time it was started.



At only 150 miles on new truck -- my money is on a faulty sensor or loose connector somewhere

I agree with you, after limping it home last night I got in it this morning and the engine light was off. I drove it around town for an hour and it never came back on and seemed to be running fine. The auto parts store says they can’t get any codes if the engine light isn’t on and the dealer is closed today. I’ll just keep driving it until it does it again and try to get the code to let everyone know what it is.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #6 ·
nobody here can help you unless you know what code it is throwing.
Went to the dealer today and they said the code was po735 which is a transmission code. They think it was just a hiccup in the computer. Does that sound normal to you guys?
 

·
Registered
Joined
·
6,772 Posts
'uhNo
Computers don't get 'hiccups'.
 

·
Registered
Joined
·
1 Posts
Low def goes to reduced speed limit, not to reduced power.

Even if it was empty, the first reduced speed limit is to 65 mph, after 500 miles. It runs a countdown screen that cannot be dismissed during the 500 miles.


If it was under 300 miles til DEF empty (and it only has 150 miles total on truck) it would have been giving 'miles to empty' warnings every time it was started.



At only 150 miles on new truck -- my money is on a faulty sensor or loose connector somewhere
 

·
Registered
Joined
·
34 Posts
Just got a gmc 2500. I’ve had it for a week it has 150 miles on it now and after taking a 20 minute ride down the interstate I got an engine power reduced message, the engine light came on and the truck would barley move. Taking it to the dealer tomorrow. Has anyone had this problem with a new L5P?
This happened to my 2018 when it was new. It was not easy to diagnosis because it occurred during short trips around home and managed to hobble home. When I would get in it the next day to drive it to the dealer, everything would be OK. It happened once when my dealer had the truck to spray the bed liner. After their own experience, they finally figured out that it was a defective valve body in the transmission that was sticking in a lower gear.
They changed out that valve body and it never happened again.
I hope this helps you solve your problem.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #10 ·
This happened to my 2018 when it was new. It was not easy to diagnosis because it occurred during short trips around home and managed to hobble home. When I would get in it the next day to drive it to the dealer, everything would be OK. It happened once when my dealer had the truck to spray the bed liner. After their own experience, they finally figured out that it was a defective valve body in the transmission that was sticking in a lower gear.
They changed out that valve body and it never happened again.
I hope this helps you solve your problem.
Thank you for the helpful information. I’ll definitely keep this in mind if I run into the issue again. I have 12k miles now and haven’t had an issue.
 

·
Registered
Joined
·
2 Posts
I agree with you, after limping it home last night I got in it this morning and the engine light was off. I drove it around town for an hour and it never came back on and seemed to be running fine. The auto parts store says they can’t get any codes if the engine light isn’t on and the dealer is closed today. I’ll just keep driving it until it does it again and try to get the code to let everyone know what it is.
Hi I have the same problem today so what I need to do?
 

·
Registered
Joined
·
2 Posts
It shows reduce engine power the only thing I know it maybe missing it’s DEF fluid but it has 27% left so I don’t think that was the problem
 
1 - 13 of 13 Posts
Top