2002 chevy trailblazer

[plowking_90]

my gf has a 2002 chevy trailblazer and i noticed today that the 4 wheel drive switch isnt working at all it usualy lights up on what its on and the swith does nothing now, anyone have a clue???

[DnStClr]

It's possible there's a problem with the control module. Do you have an OBD2 tester to read codes? if not, you might have to take it to the dealer to see what codes it's throwing. !st thing to do is to disconnect the battery for 30 seconds ,reconnect, and see if the light resets .

[plowking_90]

i disconnected the battery and it reset itself, dont know why it happend? thats y i stick with the older stuff. no computer stuff

[DnStClr]

It's possible that ya might see it happen again. I hope not. But the dealer will charge @$500 or so if the control module is bad. The module electrically controls an actuator that moves a forked link at the front transfer case to engage the front wheel drive. Sometimes the link needs replaced. I Hope it's fixed.

[HAULIN IT]

Plowking, In 2002 there were two Trailblazers. The old "S" platform with a nice trim / interior package & the first year for the "new" Trailblazer. I'm guessing you have the "S", it is known for 4wd problems. The switches do go bad, feel the buttons as you push them to see if they all feel the same, sometimes one will lose it's positive feel. The other thing you can check that costs nothing is: Remove the Right kick panel, there is a silver box, it's the control module. It will re-set, as you stated when the power is disrupted. Unplug it & look at the pin/plug connection for corrosion. The control module do go bad also & the encoder motor on the transfer case is also a common problem. After checking the switch carefully & looking at the plug on the module, you will need to get it to someone with knowledge of these (or a known good part to try). If you have a "new" style Trailblazer, disregard this post. Good Luck, Lorne

[VileZambonie]

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(R).

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(R).
 
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.

Important: For the 2002 model year, the TCCM must be replaced and reprogrammed.
 

Warranty Information

 
 
 
 


For vehicles repaired under warranty, use the table.

 
 
 
 


Disclaimer

[DnStClr]

Wow. New control module,new software and labor- hope mine doesn't go out in my 2002 Duramax. I'm not surprised to see the Tech Service Bulletin. I've seen other websites where they've been troublesome.