GMC Sierra 2500 HD Questions

Get answers to questions about your GMC Sierra 2500 HD at RepairPal. Find solutions, diagnose problems and get back on the road.

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We have alldata, they show us a location of where it should be, however we have searched this truck, top to bottom, and cannot find the fuel pump flow control unit. It is a closed system so how does it monitor the fuel flow?

Horn works normally when truck is cold and not running. Works when truck is started. Stops working as soon as transmission put in D and brake pedal released. Will not work again until truck turned off and cooled down. I have changed the horn relay- no change. What next? Scan tool?

vehicle on its own, just happened out of the blue, with no other concerns.

I turn it off, try again, it may take 2 or 3 times then it will start normal. It sounds like the starter is cranking, but it either doesn't start, or it starts, runs rough for a second, then it runs fine

The brake lights still work but my cruise control has stopped working. The wires are colored but the switch only has the letters A B C D E and F as identifiers for the wires. How can I find out which terminals the 3 broken wires connect tro?

only happens in 4wd lo or hi

I'm trying to change my plug wires and want to make sure they are put on correctly.

Have to turn radio off for 2 to 3 minutes then back on for the scanning to stop

Ran diagnostic and these where results: 1. P0654 ENGINE SPEED 2. P0758 2-3 shift 3.P 2761 TCC/ PCS solenoid 4. U 0107 lost communication 5. U 1041 lossEBCM/EBTCM 6. C0035 LiFT fr SPEED. Had another test run and was told it needs throttle body, & may need more repairs. At estimated $700 or more. Now I'm broke down 800 mls from home and low on cash I need help

Push the peddle and no power.

Trying to fix my ABS breaking system. I need a schematic.

Is there a way to by pass the power steering unit and isolate the breaking system, so they work if the power steering unit goes out? 8100 engine (gas) with Allison Transmission.

Can't get the app to get past "resyncing data"......... uninstalled and reinstalled and still no luck regardless of if i'm on wifi or not. Any suggestions would be appreciated. Online version working fine though!

Can't get the app to get past "resyncing data"......... uninstalled and reinstalled and still no luck regardless of if i'm on wifi or not. Any suggestions would be appreciated. Online version working fine though!

Can't get the app to get past "resyncing data"......... uninstalled and reinstalled and still no luck regardless of if i'm on wifi or not. Any suggestions would be appreciated. Online version working fine though!

I just took my truck out after months of sitting idle. There is evidence of rat tearing. My truck now has a warning message to check the 4x4 system and the airbag. I inspected and only found that the rats ate the wires on the coolant level sensor connector. My AC is also not working and makes a lot of noise. Can you tell me what the problem might be?

Tiene algun orificio de lubricacion el cardan de la transmission proveniente del motor por donde SE pueda escurrir y perder todo el aceite de la transmission si SE dañara algun sello?

I drilled out my ignition cylinder too far, ( in the dark)....I now need to install the case, and the I need to pull the steering wheel?..if so, can u give me step by step instructions please?
Signed...using power tools without light..:(

Had it replaced @ 40000 miles due to metal shearing off in the system. Happened again at 80000 miles but repaired instead of replaced. Now again at 166000, needs replacing. To the tune of $12000.00. Is this normal? I've driven vehicles for 40 years and never had this happen before.

I got my truck stuck several weeks ago in a huge off-road mud pitt...ever since, I've had infrequent shifting issues. Some days it's fine and other days it would shift a little rough and the dash lights wouldn't move as I shifted through the gears.

It runs just as strong but now it won't shift out of 3rd or 4th gear. The RPMs are so high at 45 miles an hour but it won't shift through the rest of the gears or kick down.

I'm really thinking it's somethiing electronic but it's slightly out of my area of expertise.

My automatic door locks quit working about this same time.

Any ideas? I'd apreciate the the assist !

Battery is good fuses are good was driving and it shut off Will not start back

happens occasionally

Years ago I installed a open air filter box that had a K&N filter on it. I started getting the P0101 code. I was told that the maf doesn't like the oil that is used in the filter. I replaced the K&N filter with a cone shaped dry filter. I also took the maf out and cleaned it with some electrical cleaner but still get the code off and on. I don't really notice a difference in the way it runs. I decided the other day to purchase a new maf sensor and put it in and after I drove it awhile the code came back. My question is can having an open air box cause it to get to much air causing the code or do I need to look for other problems.

I have a manual dual a/c controller. A couple months ago the lights went out on the controller but still worked fine. Then right after that is was blowing hot on the driver side and cool on the passenger side. But after starting it over and playing with the controller it started working fine again. Now it's not blowing at all and making a ticking sound behind the controller or passenger side dash. Does anyone know what is causing this or what I need to fix?

Truck had a surge at 1100 rpm for a while, then the check engine light came on. I drove it like three times since...the last time I was stopped at a light when my truck just died right warning no bad noises or idles. It hasn't started code P0673 when I scanned it...but I didn't think glow plugs would cause my truck to die and not start again! I replaced both batteries, the fuel filter and the fuel water seporator.....PLEASE HELP I'M A GIRL! LOL