July 22nd, 2015, 6:50 PM
Last edit by: IB Advertising
- Chevrolet Silverado GMT800, GMT900, and K2XX 4WD General Information and Maintenace Schedule
Important information to help you understand your Silverado.
"service 4-wheel drive"
December 7th, 2015, 5:46 AM
#12
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Hey guys, so I've read through plenty of forums about the 4wd issues on these trucks. My problem seems to be different than everyone else.
Problem: 4wd drive switch has no lights, I have no service 4wd lights on dash, truck is still in 2wd and does not switch into 4hi or 4lo.
Fixes:
1. I have checked every fuse that relates to any part of the 4wd system.
2. I have replaced the 4wd push button switch.
3. I have cleaned the ground connection underneath driver side door.
Hear me out. I've read the actuator can be bad and the encoder motor also, but I've also read that even if these items are bad the lights will still be lit up on the switch. I have a brand new switch, yet still no lights. I've read that the TCCM that functions with the 4wd that is located on the passenger side kick panel can go bad. Could that be my issue? There is not much information about it. Also, are there other grounds that I can troubleshoot besides the one beneath the drivers door frame?
Problem: 4wd drive switch has no lights, I have no service 4wd lights on dash, truck is still in 2wd and does not switch into 4hi or 4lo.
Fixes:
1. I have checked every fuse that relates to any part of the 4wd system.
2. I have replaced the 4wd push button switch.
3. I have cleaned the ground connection underneath driver side door.
Hear me out. I've read the actuator can be bad and the encoder motor also, but I've also read that even if these items are bad the lights will still be lit up on the switch. I have a brand new switch, yet still no lights. I've read that the TCCM that functions with the 4wd that is located on the passenger side kick panel can go bad. Could that be my issue? There is not much information about it. Also, are there other grounds that I can troubleshoot besides the one beneath the drivers door frame?
January 9th, 2016, 4:57 PM
#13
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Location: Princeton Minnesota 55371
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Ive been having the Service 4WD message on start up on my 01 Silverado, the push buttons don't light up or do anything. I replaced the push button switch but still had the problem. I took it in for service and they replaced the actuator and that didn't help so they removed it, said i needed a rebuilt or new Transfer case. I didn't replace it. then one day it worked and i told them there must be some corrosion on the wiring, or a corroded connector. They checked that and then said i need a new TCCM transfer case control module. I kept reading about shutting the engine off and restarting it. that didn't work. Then i tried a different routine for starting, I turn the key to the run position and watch the lights on the push buttons and when they settle down, start the engine. I have done that the last dozen times, then when i start the truck. the Service 4WD message stays OFF and the push button Auto 2WD hi low 4WD selector switch works every time. After ignoring all the list of possible cures this WORKED I think a lot of electrical problems come from poor connections and by replacing a $200 whatzit the connections have to be re seated and the component works, dah, and didn't need to be replaced after all. Maybe there is another explanation for why this worked. Id like to hear about it.
January 9th, 2016, 9:14 PM
#14
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Chevy Truck Song
To all my Chevy Truck enthusiasts.
Enjoy my new song.
Hoping this will help you all have a great new year in 2016.
https://www.youtube.com/watch?v=zPbw...ature=youtu.be
Enjoy my new song.
Hoping this will help you all have a great new year in 2016.
https://www.youtube.com/watch?v=zPbw...ature=youtu.be
January 10th, 2016, 11:34 AM
#15
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My opinion is its an intermittent issue and may come back, theres really no actual explanation why letting all the self tests run before you start the engine would make any difference on the 4x4 system.
January 12th, 2016, 10:42 PM
#17
CF Junior Member
Okay, as you can see from my post above, the fix lasted 3 years. I don't use my 4WD very often, so I could probably calculate a cost per button push for my truck. I can't really ever see me owning a Toyota truck, but I can't help but wonder if they have the same problems.
Well, it happened again. I was starting to get stuck, I pushed my 4WD button to go to 4WD high, it changed to 4WD okay and I got myself out of the mudhole, but when I tried to go back into 2WD, it refused to do so and as it sensed my defeat, it flashed up the 2" square message that says Service 4WD.
Did some reading and decided to replace the 4WD selector switch or the buttons I pushed till my fingers were numb in the hopes I could switch from 4WD to 2WD. This $70 part did not fix the problem although I read countless posts saying 9 times out of 10 it does. I found the grounds that are under the driver side door and cleaned them and reinstalled. I left my negative battery cable disconnected for almost an hour while I did this in case there was some code that needed to be cleared. I had the same problem though when I started my truck. The selector switch assy blinks on each of the buttons when I start my truck, but they immediately go out and whereas one of the buttons should be lit if everything is working correctly, none of them are and the Service 4WD message is still proudly being displayed.
I am at a fork in the road of dumping my 401K on the service counter of a local dealership, or continuing with my shotgun troubleshooting methods and replacing another part that lots of forum postings say fixes the problem 9 times out of 10 and that is the front differential actuator, which is another $70 part. I also had my fluids replaced for both front and rear differentials and also for the transfer case as I had read on one posting that fluid getting low can cause this.
I wanted to get my codes read, but they can't be read by OBDII scanners, but has to be Tech 2, which are more than I want to spend right now. I figure I can keep throwing parts at it and still not be at the cost that my mechanic charged me 3 years ago to replace the actuator. At least that way, I will have a bunch of 4WD parts laying around that I can use when those parts actually go bad.
Does anybody have any ideas? I have been in 4WD since Christmas telling everyone when the 4WD goes out, I will just go get another truck, but I really don't want the truck payment.
Thanks.
Well, it happened again. I was starting to get stuck, I pushed my 4WD button to go to 4WD high, it changed to 4WD okay and I got myself out of the mudhole, but when I tried to go back into 2WD, it refused to do so and as it sensed my defeat, it flashed up the 2" square message that says Service 4WD.
Did some reading and decided to replace the 4WD selector switch or the buttons I pushed till my fingers were numb in the hopes I could switch from 4WD to 2WD. This $70 part did not fix the problem although I read countless posts saying 9 times out of 10 it does. I found the grounds that are under the driver side door and cleaned them and reinstalled. I left my negative battery cable disconnected for almost an hour while I did this in case there was some code that needed to be cleared. I had the same problem though when I started my truck. The selector switch assy blinks on each of the buttons when I start my truck, but they immediately go out and whereas one of the buttons should be lit if everything is working correctly, none of them are and the Service 4WD message is still proudly being displayed.
I am at a fork in the road of dumping my 401K on the service counter of a local dealership, or continuing with my shotgun troubleshooting methods and replacing another part that lots of forum postings say fixes the problem 9 times out of 10 and that is the front differential actuator, which is another $70 part. I also had my fluids replaced for both front and rear differentials and also for the transfer case as I had read on one posting that fluid getting low can cause this.
I wanted to get my codes read, but they can't be read by OBDII scanners, but has to be Tech 2, which are more than I want to spend right now. I figure I can keep throwing parts at it and still not be at the cost that my mechanic charged me 3 years ago to replace the actuator. At least that way, I will have a bunch of 4WD parts laying around that I can use when those parts actually go bad.
Does anybody have any ideas? I have been in 4WD since Christmas telling everyone when the 4WD goes out, I will just go get another truck, but I really don't want the truck payment.
Thanks.
January 13th, 2016, 1:22 PM
#18
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without codes all you can do is guess, you do not have to use a tech2 any actual scanner will work and I'd imagine some "code readers" would also.
In my personal experiences the position sensor inside the shift motor and/or the motor itself are the cause of the majority of 4x4 issues BUT having no code to go off you have no direction to focus other than swapping new parts which really sucks because new doesn't always mean good.
In my personal experiences the position sensor inside the shift motor and/or the motor itself are the cause of the majority of 4x4 issues BUT having no code to go off you have no direction to focus other than swapping new parts which really sucks because new doesn't always mean good.
January 13th, 2016, 2:28 PM
#19
CF Junior Member
Yeah, that makes perfect sense. I did get my codes pulled at AZ the other day and only came up with my standard P0446 and about a half a dozen related backfire, fuel, catalytic related entries I really need to take care of before my next inspection. But, my 4WD issue is the most pressing because I am scared I am going to burn it up using it all the time.
Is there something special you have to do to get the codes off of the TCCM if you are only using an OBDII scanner, because the 4WD codes sure didn't come up when AZ checked them for me. I always thought the cheapie scanners can only pull the P series codes, but you really have to lay down some cash to get a scanner that will pull up the C series codes, which would include the ones I am interested in since they would have to do with the 4WD and power train.
I saw in a posting for a mid-90's chevy truck how they would run a jumper from the connector on the TCCM to the port for the OBD2 under the dash by your knees, then when they turned the key on, they would look at the flashes on the 4WD buttons and the flashes would tell you what the codes were.
Is there something special you have to do to get the codes off of the TCCM if you are only using an OBDII scanner, because the 4WD codes sure didn't come up when AZ checked them for me. I always thought the cheapie scanners can only pull the P series codes, but you really have to lay down some cash to get a scanner that will pull up the C series codes, which would include the ones I am interested in since they would have to do with the 4WD and power train.
I saw in a posting for a mid-90's chevy truck how they would run a jumper from the connector on the TCCM to the port for the OBD2 under the dash by your knees, then when they turned the key on, they would look at the flashes on the 4WD buttons and the flashes would tell you what the codes were.
