Jump to content



Photo
- - - - -

Service 4wd Message And Scan Codes


  • Please log in to reply
3 replies to this topic

#1 hpracing10

hpracing10

    Enthusiast

  • Member
  • 111 posts

Posted 15 December 2009 - 02:39 PM

2003 silverado halfton- been getting the service 4wd message each time I start my truck, and I can't shift out of Auto4wd. Also, whlie in Auto4wd, when the back wheels spin, the front don't engage so all-in-all, the 4wd is not working. I took my truck to a gm dealership to scan for codes and it came back with 10, YES 10 different codes that were coming from the transfer case he said. I would like some advice as to where I should start. He said that most times if the code B2725 is thrown, in MOST cases it is the dash switch. But why am I getting so many others? Someone please help!

BO790-transfer case nuetral indicator circuit malfunction
CO550-ECU malfunction
CO379-front axle control circuit malfunction
CO374-general system malfunction
CO359-discrete output circuit malfunction
CO306-motor A/B circuit malfunction
CO300-rear propshaft speed sensor malfunction
U1301-class 2 communication circuit low volts
B2725-mode switch circuit malfunction
U1000-class 2 data link malfunction

#2 Matt_

Matt_

    Senior Enthusiast

  • Member
  • 5,108 posts
  • Location:central NJ

Posted 15 December 2009 - 04:45 PM

First.... check your fuses!! :cheers:

Second... I'd try this:

Bulletin No.: 02-04-21-006E

Date: July 20, 2006

TECHNICAL
Subject:
Inoperative 4WD/AWD Lamps, Inoperative 4WD/AWD System, DTC C0550 Set, No Communication with TCCM (Reprogram Transfer Case Control Module)

Models:
2004 Buick Rainier
2002-2004 Chevrolet TrailBlazer, TrailBlazer EXT
2003-2004 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2002-2004 GMC Envoy, Envoy XL
2003-2004 GMC Sierra, Yukon, Yukon XL
2004 GMC Envoy XUV
2002-2004 Oldsmobile Bravada

with Electronic Shift or Active Transfer Case (RPOs NP1, NP4 or NP8)

Supercede:

This bulletin is being revised to add Subject information and change the labor operation. This bulletin cancels and supersedes Bulletin Number 03-04-21-006. Please discard Corporate Bulletin Numbers 02-04-21-006D and 03-04-21-006 (Section 04 - Driveline/Axle).

Condition

Some customers may comment that the 4WD/AWD indicator lights on the selector switch do not work, or the 4WD/AWD system may be inoperative and/or the service 4WD light is illuminated. The condition is typically intermittent and always occurs at key-up. Upon investigation, the technician may find DTC C0550 set.

Cause

The Transfer Case Control Module (TCCM) has not received the wake-up call during key-up and has remained in the "sleep mode".

When the TCCM is in the "sleep mode", it will not communicate with the class II bus or the Tech 2.

Correction
1. Try to communicate with the TCCM. If no communication, go to step 2. If communication is possible, go to step 5.

2. Remove the underhood (ATCM or TREC) TCCM fuse.

3. Wait 30 seconds.

4. Reinstall the fuse. The module should wake up and communicate with the Tech 2.

5. Check for codes in the TCCM. If a C0550 is found current or in history with or without other codes, replace the module and go to step 6.

6. Reprogram the TCCM with the latest TIS software using normal SPS procedures.

7. Verify operation and that no codes are present.



Third.... I'd clear all of the codes and see what comes back. Some of those could have been from previous work done on the truck and are not "active" codes.
When Hell Freezes Over, I'll Ski There Too!!
Sig550x200_zpsfce041b6.jpg
2007 Jeep Commander 5.7L Hemi: Pics Here
2008 GMC Sierra Denali AWD (SOLD):Pics Here
2005 1500 Crew Cab. 8" lift w/37s (SOLD): Pics Here

#3 hpracing10

hpracing10

    Enthusiast

  • Member
  • 111 posts

Posted 15 December 2009 - 07:59 PM

thanks sk1er18. I just tried removing that fuse, had it out for 30 seconds and put it back in then started the truck and it didn't do anything. Also, I checked the fuses, they all checked out OK but I replaced them anyway. I could have the codes reset, but I don't know if I want to spend another $60 for diagnostics again. What would you say that I start with? A new switch is only $48 from gmpartsdirect.com. If that doesn't work, do I move to the front diff actuator, or the transfer case encoder motor on the side of the TC? Thanks

#4 Matt_

Matt_

    Senior Enthusiast

  • Member
  • 5,108 posts
  • Location:central NJ

Posted 15 December 2009 - 08:11 PM

With all of those codes you'll end up spending $1000+ throwing parts at it. They should have cleared the codes to start with.....

Only one thing is certain in this situation... if ALL of those codes are the result of the same problem, it sure as hell isn't the dash switch.

Take a good look at all of the sensors, actuators, etc on the drivetrain. make sure all of the plugs are in good shape and making contact and follow the wiring to make sure one of the harnesses didn't get cut/damaged.
When Hell Freezes Over, I'll Ski There Too!!
Sig550x200_zpsfce041b6.jpg
2007 Jeep Commander 5.7L Hemi: Pics Here
2008 GMC Sierra Denali AWD (SOLD):Pics Here
2005 1500 Crew Cab. 8" lift w/37s (SOLD): Pics Here




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users