Jridenour694
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I have a 2009 GMC Sierra 1500 with the 5.3 L Flex Fuel engine. About two months ago I came out to go to work and it was in 4-HI and would not shift back into 2WD. I pulled the transfer case shift motor and got it back into 2WD but after a few key cycles it was back in 4-HI. I pulled the fuse and left it out and it stays in 2WD obviously. Since then I have replaced the shift motor, 4WD actuator, Dash Switch, cleaned the grounds off and made sure I was getting a good ground, and replaced the fuse under the dash as well as checking all of my connections and wires to make sure they are good. When you pull the fuse you can hear it shift out of 4WD, and when you put it back in and turn the key on you can hear it shift back into 4HI. The “Service 4WD” message is flashing on the dash but the check engine light does not illuminate and no code is present until you pull the fuse then of course you get the “Cannot communicate with TCCM” code. The lights on the 4WD shifter knob all illuminate when the key is first turned on with the fuse in, then go out and stay out. I did disconnect the battery and let it sit and drain the charge out of the computer, then reconnected it and let it idle and “relearn” everything. Now the lights on the 4wd switch come on when you start the engine then go out and the 4-HI light stays on and the truck stays in 4wd regardless of the switch position. Pulling the fuse is the only way to get it to come out of 4wd.
Does anyone have any ideas as to what else I can check or change? I’m no mechanic by far but I can turn a wrench the correct way to replace a part if needed.
I have not driven it much with the fuse in to see if the check engine light does eventually come on since I mostly drive the truck back and forth to work and that’s about it. Its a 5 minute drive to work and back and I don’t know it that would be enough time for the check engine light to come on and a code set. Right now I am just driving it with the fuse out and the 4WD inoperative.
Another note, I was not hearing any shifting from the transfer case motor until I cleaned the ground for the TCCM then it started shifting in and out of 4WD when you pull the 4WD fuse. But that’s the only time the shift motor engages.
Does anyone have any ideas as to what else I can check or change? I’m no mechanic by far but I can turn a wrench the correct way to replace a part if needed.
I have not driven it much with the fuse in to see if the check engine light does eventually come on since I mostly drive the truck back and forth to work and that’s about it. Its a 5 minute drive to work and back and I don’t know it that would be enough time for the check engine light to come on and a code set. Right now I am just driving it with the fuse out and the 4WD inoperative.
Another note, I was not hearing any shifting from the transfer case motor until I cleaned the ground for the TCCM then it started shifting in and out of 4WD when you pull the 4WD fuse. But that’s the only time the shift motor engages.