I have a 2000 Tahoe that I traded for a motorcycle. Have a service 4WD light on, it was grabbing like it might be in 4WD and the transmission was slipping. Had the transmission rebuilt, have replaced the 4WD switch on the dash, transfer case control module, 4WD actuator in the front differential, another transfer case shift motor. Still have the service 4WD light, but I still have to put the front driveshaft back in and replace the crossmember before I can lower it and see if it's drivable. Any ideas?
2000 Tahoe service 4WD light
- Thread starter rjybilcom
- Start date
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Put a scanner on it and see what code(s) you're getting for the 4WD system; there's a code that goes with the message. A Tech 2 would be an excellent scanner to use.
I have a basic scanner but I don't think it picks up transmission codes.
The 4x4 code would start with a "C".
Some auto parts places have a little more advanced scanners that will read these codes; they'll either come out and read them for you or loan you the scanner to use in their parking lot.
Some auto parts places have a little more advanced scanners that will read these codes; they'll either come out and read them for you or loan you the scanner to use in their parking lot.
MassHoe04
Full Access Member
I wasn't having anything that felt like "grabbing" or any other symptoms, but I did have Service 4WD message on my information center display.
Some of our experienced members suggested I might have a dirty commutator on the 4WD actuator.
They may have been right. After selecting the different modes a few times up and down the buttons, switching in and out of every mode a couple of times.
I never had the message return.
Now, when I think of it, I will shift out of 2WD and exercise the actuator in and out of the other 4x4 modes a few times.
Usually on a gravel parking lot or very short distances on pavement that are straight.
I like the gravel lot and use that most of the time, running the different modes in forward and reverse.
I also put into 4L, because I know that was probably never done before by PO.
Note to anyone with just the message on the info. center display and no other weird 4x4 symptoms or noises: Before replacing parts, try exercising the actuator with hitting the different buttons to move from mode to mode first. It may fix itself just by getting exercised a bit. I feared the worst at first, then ended up having to basically do nothing involving parts or money.
Some of our experienced members suggested I might have a dirty commutator on the 4WD actuator.
They may have been right. After selecting the different modes a few times up and down the buttons, switching in and out of every mode a couple of times.
I never had the message return.
Now, when I think of it, I will shift out of 2WD and exercise the actuator in and out of the other 4x4 modes a few times.
Usually on a gravel parking lot or very short distances on pavement that are straight.
I like the gravel lot and use that most of the time, running the different modes in forward and reverse.
I also put into 4L, because I know that was probably never done before by PO.
Note to anyone with just the message on the info. center display and no other weird 4x4 symptoms or noises: Before replacing parts, try exercising the actuator with hitting the different buttons to move from mode to mode first. It may fix itself just by getting exercised a bit. I feared the worst at first, then ended up having to basically do nothing involving parts or money.
wjburken
Supporting Member
One thing that I’d recommend, in addition to all that’s already been suggested, is checking the fluid condition and level in the transfer case to make sure everybody is good there.
rockola1971
Full Access Member
Yup. Thats the stereotypical behavior and fix of a dirty commutator in the Tcase shift motor. They get worn and dirty from sitting in the same spot which is usually 2wd for long periods of time. The commutator can be replaced individually but the shift motor of course has to be yanked down to do it.
InterceptorF
Member
You need to validate the ground wire behind the intake to the block is good as well as the two ground wires under the driver door.
Rolexus
Member
- Joined
- Aug 2, 2021
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Yup - it’s been awhile, but I followed this suggestion a few years ago. I found the black ground wire in the harness (drivers side, near manifold) and created another ground off of this wire (splice into but leaving original in tact), attaching this ‘new‘ ground directly to a grounding point on the fire wall. Helped to super-ground the system
