Get an AlldataDIY Repair Info Subscription Special Thanks To: AC Kits.com

Author Topic: 4WD on a 1999 GMC jimmy  (Read 10043 times)

Offline 1999gmcjimmy

  • Newbie
  • *
  • Posts: 10
4WD on a 1999 GMC jimmy
« on: January 17, 2008, 07:10:22 AM »
 I have a 1999 GMC Jimmy and the 4WD doesn't work, It has the control on the dash and it has the automatic 4WD option on the switch.  When you turn the key on the entire switch lights up and the transfer case mod makes all kinds of switching noises and the lights on the switch flash and then go out except for the two wheel drive .  The switch in the dash was replaced and the controller on the transfer case was replaced and what i noticed is the transfercase is locked in 4WD.  The diff isn't locked so the power isn't getting to the front wheels but I can't turn the front drive shaft with the rear wheels on the ground but if you jack up the rear wheels and the car isn't in park i can turn the rear wheels by turning the front driveshaft so that is how i know the transfer case is locked in 4WD.  I've checked all the basic stuff like relays and fuses connections but I'm at the point were i don't know what elts to check for and the last mecanic just started guessing and replacing parts, I need to find the problem and fix it. 

Offline crunch

  • BAT Mechanic Member
  • wrench
  • *
  • Posts: 2077
Re: 4WD on a 1999 GMC jimmy
« Reply #1 on: January 17, 2008, 09:28:33 AM »
How many miles on it?
Has it ever been serviced with the new blue GM transfer case fluid?
Any sevice transfer case or check engine lights on?
You need to find a good repair shop with a engine /transfer case/transnmission scanner.
Get the transfer case data read out and code checked and shifting test in scanner done.
Post back any codes.
Crunch
« Last Edit: January 17, 2008, 09:30:42 AM by crunch »
OEM parts only hurt one time Crunch said that.
Cheap after market stuff will bite you many times. My brother in law is learning that the hard way.

Offline kev2

  • BAT Mechanic Member
  • wrench
  • *
  • Posts: 3408
Re: 4WD on a 1999 GMC jimmy
« Reply #2 on: January 17, 2008, 11:34:51 AM »
I agree with my colleague....BUT want to add

  I have just read -yesterday- a test for TCCM codes, I have NOT tried this

but lets see if it will isolate codes, let me know if it works...

-----------------------------------------------------------------------------Transfer Case - NVG 233-NP1 (Two Speed Selectable) 
 
Obtaining Diagnostic Trouble Codes
The diagnostic trouble codes are displayed on the three transfer case shift select buttons. The shift select buttons are located to the right of the instrument panel cluster. When pin 13 of the data link connector is grounded and the ignition switch has been in the OFF position for at least five seconds prior to positioning the ignition switch to the RUN position, the shift select buttons will blink a number of times in order to indicate a diagnostic trouble code from 1 to 4.
Position the ignition switch to OFF. Ensure the ignition switch is positioned to OFF for at least 5 seconds.
Connect pin 13 on the data link connector to a vehicle ground source. The data link connector is located in the cab under the instrument panel on the drivers side.
Position the ignition switch to RUN.
Note the shift select buttons for blinking codes. Refer to Perform a Diagnostic on the TCCM .
If the shift select buttons all blink one time and stop, and do not continue to blink, no fault codes are stored in the TCCM.
The transfer case shift select buttons will blink in order to identify any stored DTC. If only one code is stored in the TCCM memory, that code will blink repeatedly with a three second delay between blinking sequences. If more than one code is stored, the first code will blink once, then after a three second delay, the next code will blink. This sequence will continue until pin 13 is no longer grounded.
When reading the diagnostic trouble codes, the number of shift select buttons blinks will indicate the code number.

 

Offline crunch

  • BAT Mechanic Member
  • wrench
  • *
  • Posts: 2077
Re: 4WD on a 1999 GMC jimmy
« Reply #3 on: January 17, 2008, 11:44:40 AM »
Kev 2
Pin 13 test is Only on a 233 transfer case.
The ground pin 13 will not work on the auto matic 236 0r 246 transfer case.
It is a scanner only deal on 236/246.
Crunch
OEM parts only hurt one time Crunch said that.
Cheap after market stuff will bite you many times. My brother in law is learning that the hard way.

Offline kev2

  • BAT Mechanic Member
  • wrench
  • *
  • Posts: 3408
Re: 4WD on a 1999 GMC jimmy
« Reply #4 on: January 17, 2008, 12:26:44 PM »
live and learn.....I saw only 2 t cases f0r this year  233 and auto 236 somehow I thought 233 ....

Offline crunch

  • BAT Mechanic Member
  • wrench
  • *
  • Posts: 2077
Re: 4WD on a 1999 GMC jimmy
« Reply #5 on: January 17, 2008, 01:17:29 PM »
10-4 on the two.
236 has the automatic 4W button on switch.
Crunch
OEM parts only hurt one time Crunch said that.
Cheap after market stuff will bite you many times. My brother in law is learning that the hard way.

Offline 1999gmcjimmy

  • Newbie
  • *
  • Posts: 10
Re: 4WD on a 1999 GMC jimmy
« Reply #6 on: January 18, 2008, 07:06:46 AM »
There is no codes?

Offline crunch

  • BAT Mechanic Member
  • wrench
  • *
  • Posts: 2077
Re: 4WD on a 1999 GMC jimmy
« Reply #7 on: January 18, 2008, 10:03:36 AM »
There is no codes?

Did you get it put on a transfer case capable scanner or just check for OBD11 code?
If it is not shifting there will be code/codes.

Did you go threw the shift  test on the scanner?
Crunch
OEM parts only hurt one time Crunch said that.
Cheap after market stuff will bite you many times. My brother in law is learning that the hard way.

Offline 1999gmcjimmy

  • Newbie
  • *
  • Posts: 10
Re: 4WD on a 1999 GMC jimmy
« Reply #8 on: January 20, 2008, 07:11:55 AM »
The dealer looked at it and a mechanic who does nothing but work with computer stuff looked at it and no one can tell me whats wrong with this truck.  According to lights on the dashboard it's in 2WD and because it don't shift you cant do that shift test thinggy.  I have been a mechanic for 28 years now and when i get into something i know nothing about i send it to someone who claims to know how to fix such a problem like a dealer.  I do front end, brakes, suspention, drive train, water pumps, alternators, R&R engines, trannys, exhaust, all the good stuff.  When it comes to computer stuff i'm in the dark, well not so much now i am learning, but some of it is just way over my head.  Now in just about the last two years I've had four different jobs i sent to another garage or a dealer because i thought i couldnt figure them out and they all came back un fixed.  In the end i ended up fixing them on my own, yah it took some time a day or two one car sat in the back of my shop for a week and a half but i figured it out like what i'm probily going to have to do with this GMC.
What do these guys do if there computers and scanners don't tell them what the problem is, give the car back to the customer and tell them they cant fix it because thats what they do to me, I've spent $300 on this truck so far and i'm no better off than i was when i started.  Enough of that, well any ideas on why this thing won't shift, and don't take any of that personal I don't know any of you and maby it's I'm going to the wrong people, well then agin the dealer????

Offline kev2

  • BAT Mechanic Member
  • wrench
  • *
  • Posts: 3408
Re: 4WD on a 1999 GMC jimmy
« Reply #9 on: January 20, 2008, 09:40:48 AM »
I have looked over the diagnostics for this ......all steps require a scanner ...
And a scanner capable of bi direction,tccm capable -U,B,C, P..bla blah etc

 Sorry  not what you wanted to hear...
So as I read this trouble tree...
at start transfer case lights come on...
do any flash continously....
Do mode lights illum when that mode is pressed....
Will service indicator light come on for @2seconds...

sorry I have no way to send you the diagnostics...anyway without the corect scanner we are back to step 1

There would be a code BUT are all4 tires the same OEM size?? +-1/4"

Offline crunch

  • BAT Mechanic Member
  • wrench
  • *
  • Posts: 2077
Re: 4WD on a 1999 GMC jimmy
« Reply #10 on: January 20, 2008, 10:11:11 AM »
As kev said.
A good scanner is almost a have to have deal.
The codes and shift test built into the good scanner will lead you in the right direction.
If you are going to try to fix it yourself.
Good repair info is a have to have on it.
Factory repair manual or All Data sub.

Repair flow charts and a lot of good repair information can be found in the All Data Sub.
Upper right side of this web page.

http://www.alldata.com/products/diy/index.htmll.

Tips On going to a dealer.
Ask that only a factory certified gasoline engine transmission transfer case performance specialist work on your car.
Not all dealerships are concerned with how repairs are dispatched, and not all dealership techs bother to take advantage of the training offered by factory (the vast majority of which is paid training). If the dealer is uncooperative, ask for your money back and call around for a dealer that will accommodate you.


OEM parts only hurt one time Crunch said that.
Cheap after market stuff will bite you many times. My brother in law is learning that the hard way.

Offline kev2

  • BAT Mechanic Member
  • wrench
  • *
  • Posts: 3408
Re: 4WD on a 1999 GMC jimmy
« Reply #11 on: January 20, 2008, 10:31:42 AM »
after rereading the thread....I am wondering if we are clear on problem...

start vehicle- lights are not flashing "service" light is off..

vehicle shows 2wd/hi.....you then select 4wd ....does 4wd light come on?
no flashing?
then what happens??

A)light stays in 4wd without front axel locked....
B)light returns to 2wd...........

Offline 1999gmcjimmy

  • Newbie
  • *
  • Posts: 10
Re: 4WD on a 1999 GMC jimmy
« Reply #12 on: January 21, 2008, 03:36:30 PM »
Turn key on all the lights light up I hear switching going on then the 2WD light comes on and stays on, no matter what button is pushed it is allways showing it's in 2WD, No flashing lights, no service 4WD nothing, no codes, pretty much no problems found by any one but yet it doesn't shift into 4WD.  The dealer says there isn't a problem, so i say but it don't shift into 4WD that is a problem.  They say but we didn't find any problems, and we just go back and forth till i get PO.  So i guess it not shifting into 4WD isn't a problem I'm just going to replace parts till i get it to work .

Offline 1999gmcjimmy

  • Newbie
  • *
  • Posts: 10
Re: 4WD on a 1999 GMC jimmy
« Reply #13 on: January 24, 2008, 06:52:19 AM »
I went back to the dealer to bitch about this and i just happend to talk to the tech that checked the jimmy, he had something totaly different to tell me than the services manager.  The service manager told me there was no codes and because it won't shift they can't perfom any test, the tech said he could not get the scanner to comunicate with the tcm and that is probily what the problem is.  I guess the sevice manager didn't realize that i was a mechanic and all i wanted is to get an idea of what was wrong with this thing, Well what ever i guess I'm putting in a tcm saturday and ill let you all know what happend.  Oh ya there is no wire going to pin 13 on the diagnostic connector on this truck so i'm guessing there is no self diagnostics, but you can calibrate the switch without a scanner it's a long process but it can be done

Offline crunch

  • BAT Mechanic Member
  • wrench
  • *
  • Posts: 2077
Re: 4WD on a 1999 GMC jimmy
« Reply #14 on: January 24, 2008, 10:08:36 AM »
That may be your problem.
If the scanner will not work you have a electrical problem.
Start with fuses and power feeds.
And again before throwing parts at it get some good repair info like factory manual or the All data online sub.
Top right of theis web page.
OEM parts only hurt one time Crunch said that.
Cheap after market stuff will bite you many times. My brother in law is learning that the hard way.

 

©Copyright 2001-2013 batauto.com, BAT Auto Technical.
All Rights Reserved.
May not be reproduced without express written consent
.

Disclaimer: We cannot guarantee the accuracy of all information.
Please confirm the information with an appropriate manual
We try and make them as accurate as we can, but sometimes we all make mistakes.