Diagnosing GM Push Button 4wd Issues

EmersonHart13

John
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This is obviously not important but if I don't take care of it soon it'll be winter and I will be scrambling...

For starters I miss the stick on the floor.

97 Suburban, I bought a new switch because I thought it was that and I was wrong. The switch lights up when you start the truck and then goes dark. If you hit the buttons enough times you can get it to go in to 4wd, but even then the lights are erratic at best.

I believe whatever module controls the push button 4wd is probably going bad OR whatever reports to that module if it is in 4wd is not working right. Probably some actuator on the front axle or transfer case?

If anyone has any experience with this system your input is appreciated.

Thanks,

John
 

Eagle

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I had to replace the actuator on the front axle w/ the diesel burb. Mine had the lever, but had the same issue. 4WD light wouldn't come on most of the time. If you messed with it enough, it'd eventually go into 4, but eventually even that stopped working.

New actuator and 100% go 100% of the time nice and quick like too. :D
 

Chrisco

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^This. I was going to reply saying virtually the same thing, and all I read was the title.
 
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EmersonHart13

EmersonHart13

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4WD Actuator $51.99 from Rock Auto

That lil guy?
 
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EmersonHart13

EmersonHart13

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Don't worry, I still love you.
 
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EmersonHart13

EmersonHart13

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Thank you sir, I will order one up and crawl my lanky ass under there.
 

SRT41320

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they make a cable operated version, i ran this on my old 2000 silverado, worked great... basicaly shift into 4H or 4L and then pull a cable - supposedly will never fail. Also gives you the option for 2L if for some reason you need it.
 

Slow Buick

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they make a cable operated version, i ran this on my old 2000 silverado, worked great... basicaly shift into 4H or 4L and then pull a cable - supposedly will never fail. Also gives you the option for 2L if for some reason you need it.
EPIC BURNOUTZ
 

Slow Buick

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for what it's worth, my suburban had the same issue and it ended up being a wire that was worn through. take a look at all the wiring under the truck man.
 
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EmersonHart13

EmersonHart13

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If it isn't wiring it is either the TCCM or the Encoder motor. I believe the way the error codes go if it is a 2 or 3 it is an Encoder error, if you get 4 flashes it is the TCCM. I don't know what 1 flash means.


The error codes are:
1 - When the ignition switch is positioned to RUN the TCCM test to determine if RAM standby Power (maintained battery power) to the TCCM was lost since the ignition was last turned OFF. When power is interrupted on pin C6 of the TCCM, the TCCM stores a loss of RAM standby power.
2 - During electronic shifting, the TCCM check the motor/encoder for normal operation. If the motor/encoder does not function correctly enough times, the TCCM stores a motor/encoder failure DTC 2.
3 - The TCCM performs a test each time the electronic-shift motor is turned ON or OFF. If the motor does not function properly the TCCM stores a motor circuit failure DTC 3, and the shift select buttons blink in order to inform the driver of a problem.
4 - Each time the ignition is turned ON, the TCCM tests the memory, the program, and the internal system in order to ensure that the TCCM is operating properly. If the TCCM detects a fault within the TCCM, the TCCM stores a RAM/ROM memory failure (DTC) 4.
 
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EmersonHart13

EmersonHart13

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I have read so many threads on this it is getting silly!

Wiring Diagrams:
http://ww2.justanswer.com/uploads/therock500/2011-01-04_021941_62392162_96_suburban_3.gif
http://ww2.justanswer.com/uploads/therock500/2011-01-04_021850_62392161_96_suburban_2.gif
http://ww2.justanswer.com/uploads/therock500/2011-01-04_021736_62392160_96_suburban_1.gif

I think the logical place for me to check electrically is the switch at the transfer case, which I believe tells the TCCM the TC is in 4wd and allows power through. If that isn't work the actuator has no chance of working because that is where the power comes from, after that I need to check the switch on the front axle, which I assume tells the TCCM that the front diff is actually engaged... Those are both cheap parts so I don't mind replacing them.
 

bikrboy128

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there is also a TSB on the actuator harness. whenever i do an actuator, we order up the pigtail too.
 
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EmersonHart13

EmersonHart13

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Yeah you can switch to the electric one. I am not as worried about that because I only use it once in a blue moon. I just need it to work. I can wait for the old school one to engage.

I think the Encoder Motor is bad on the TC.
 

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