GMC Cars & Trucks - Page 4 - Popular Questions, Answers, Tips & Manuals

That depends upon what the code is.

Not an easy job due to the space being tight. You need a jack, a set of axle stands, a socket set and a set of wrenches. https://community.cartalk.com/t/how-in-the-hell-do-you-get-a-starter-out-of-a-2001-gmc-sonoma-2wd-4-3l/146170/7 ..

I would check wires at doors opening . you have to remove rubber and look for open circuit. Pull on each wire . you will see. Ground problem ??

Modern automotive systems are too complex to be guessing. For the money you spent on parts that likely didn't need replaced, you could have hired a competent mobile technician for a proper diagnosis.

The first step of the diagnosis is reading OBD2 codes for direction. But codes must be interpreted and further testing executed to make a diagnosis else it's guessing which typically causes more problems than it solves.

If you can read codes you still need a fundamental understanding of the systems and basic electrical troubleshooting skills to complete the diagnosis.

What OBD2 codes are stored?

Are you sure the injectors are metering? Just because you have pressure to the rail doen't mean that it's making it into the engine

Question edited for clarity. Replace the O-ring seal. https://www.google.com/search?q=1984+GMC+2500.+Transmission+oil+leak+at+the+shift+lever ..

remove and check housing for debris --fan damaged --motor failing

open rear passenger door on drivers side and flip up seat mounted on floor under seat

The EVAP monitor will run only when the fuel tank is between 1/4 and 3/4 full. So if you just filled the tank you'll need to wait. If its at 1/4 tank or less, add 5 gallons or until it's 1/2 full, then drive.


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The gas cap warning is a specific leak volume detected in the EVAP system. If replacing the gas cap doesnt't fix the problem then a proper diagnosis of the EVAP system (i.e. locate the leak) will likely be necessary.

clogged catalytic converter .

https://fuse-box.info/gmc/gmc-sierra-mk3-2007-2013-fuses-and-relay

A few common causes are low or dirty transmission fluid, or faulty shift solenoids. The transmission uses fluid pressure to shift the gears, and does so using electronic solenoids. If there is an issue with either of these the vehicle may experience problems shifting or transferring power to the wheels. If these are not the problem then it could be possible that the transmission is having internal faults, perhaps a worn torque converter, or transmission gears, inside of the transmission. As issues like these can sometimes be difficult to diagnose, if you are unsure, I would recommend having a professional technician look ay it.

Dexron V1

you can check the transmission fluid if its ok and also the transmission pressure

Check brakes pads/disc & check abs wirings

Wiring diagrams. https://www.google.com/search?q=2001+gmc+2500hd+headlights+wiring+diagram and https://www.google.com/search?q=2001+gmc+2500hd+headlights+wiring+pinout Plus https://www.alldata.com/diy-us/en ..

The knocking is probably the blend door actuators. They have been detached or become stuck. They operate the doors that direct the flow of air. https://www.google.com/search?q=2004+gmc+envoy+blend+door+actuator+location ..

There are some ideas here. It appears to be a known issue. https://www.google.com/search?q=1992+GMC+Jimmy+with+Vortec+4.3+won%27t+stay+running& ..

Did they disconnect the battery for some reason? It sounds the the anti-theft immobilizer is triggered. Do you have a way to check for DTC codes? https://www.google.com/search?q=2005+GMC+Denali+security+reset ..