GM TCCM Codes

[89-LX]

I have a 2001 Trailblazer with a newer transfercase, 4wd thats throwing a Service 4WD light. 4wd Kicks in just fine and operates perfectly. I'm thinking it may be a sensor or something else thats just tripping it. I was wondering if anyone could read the codes so I can possibly decide if its worth it to fix it or not. I live in Sterling Heights, work in Romulus. Thanks

 

[x-bred1]

I got a 2003 Bravada "same truck really" was doing the same thing it kept popping a code for 4wd encoder circuit "service 4wd" I changed the shift motor and everything still had the light on like it was a hard fault. Well about 3 wks later I started hearing a harsh engagement clunk and grinding so I decided to ck the fluid and guess what it was dry due to a seal failure. I fixed the leak filled it up started the truck ran it through the gears no noise and the light went out. Unfortunately the damage had already been done about 2 weeks later the chain came through the T-case, I stuck a Junkyard unit in and havent looked back since. Double ck the Fluid and Good Luck.

 

[89-LX]

I got a 2003 Bravada "same truck really" was doing the same thing it kept popping a code for 4wd encoder circuit "service 4wd" I changed the shift motor and everything still had the light on like it was a hard fault. Well about 3 wks later I started hearing a harsh engagement clunk and grinding so I decided to ck the fluid and guess what it was dry due to a seal failure. I fixed the leak filled it up started the truck ran it through the gears no noise and the light went out. Unfortunately the damage had already been done about 2 weeks later the chain came through the T-case, I stuck a Junkyard unit in and havent looked back since. Double ck the Fluid and Good Luck.

I convinced its more wiring than mechanical, but who knows. The t-case was replaced about a year and a half ago with a unit that only had 10k miles on it (bought it from darko I think is his name on here with the junkyard). The fluid was pink as pink could be when I got it.. Put the expensive blue fluid in it when I threw it in there, the whole 1.9 qts. No fluid has leaked.

The reason I think its wiring is because the wiring harness under the drivers side carpet got all destroyed and I had to rebuild a bunch of wires. I've also been getting an ABS and brake light at random times, which could be wiring also as the ABS system does work (except when the light comes on).

 

[dave89iroc]

i can pull codes but live in taylor, work in melvindale, and have no money for gas, lol

 

[89-LX]

i can pull codes but live in taylor, work in melvindale, and have no money for gas, lol

Can you pull them at your house or just work? I have no problem going out that way one day when I'm working or even when I'm not working. As long as I can get this figured out.

 

[Detroit Gearbox]

I got a 2003 Bravada "same truck really" was doing the same thing it kept popping a code for 4wd encoder circuit "service 4wd" I changed the shift motor and everything still had the light on like it was a hard fault.

Replacing parts without following the diagnostic procedures will give you results like that.
Unless you have extra parts laying around and lots of free time, don't change anything until you have properly diagnosed the problem.
Scan the vehicle first, and then if necessary print out the manufactures diagnostic procedure and follow the steps.

 

[89-LX]

Replacing parts without following the diagnostic procedures will give you results like that.
Unless you have extra parts laying around and lots of free time, don't change anything until you have properly diagnosed the problem.
Scan the vehicle first, and then if necessary print out the manufactures diagnostic procedure and follow the steps.

Exactly what I want to do. I have an extra t-case that has all good parts except for the viscous clutches which is why I replaced it. So I have all the sensors and the encoder motor. But it would be something in the hub assembly, the cable motor sensor, vacuum sensor or more.

 

[CamaroKid91Z]

The reason I think its wiring is because the wiring harness under the drivers side carpet got all destroyed and I had to rebuild a bunch of wires. I've also been getting an ABS and brake light at random times, which could be wiring also as the ABS system does work (except when the light comes on).

Check all your grounds. Ive ran into alot of intermittent ABS codes and lights due to loose or coroded grounds. Try there and get it scanned. I work at a chevy dealership in wayne and can scan it for you.

 

[x-bred1]

Replacing parts without following the diagnostic procedures will give you results like that.
Unless you have extra parts laying around and lots of free time, don't change anything until you have properly diagnosed the problem.
Scan the vehicle first, and then if necessary print out the manufactures diagnostic procedure and follow the steps.

I totally agree with you thats why if you look reread my post I said it was popping a code for the encoder motor I did all the wiring test per AllData then went ahead with the changing of the shift motor that has the encoder inside of it. I tried to clear the code prior everything else ck'd out I never saw a leak but there was one because the case was empty. Thats why I told him to ck the fluid 1st then go from there. Oh and I did have the other shift motor laying around so it was no biggie.

 

[89-LX]

Check all your grounds. Ive ran into alot of intermittent ABS codes and lights due to loose or coroded grounds. Try there and get it scanned. I work at a chevy dealership in wayne and can scan it for you.

What dealer? The one off Ford Rd? What times are good for you? I don't think I will be out that way till next week sometime. Does the TCCM store codes or do they have to be active to read?