SERVIVE 4WD message

Red2500HD · October 15, 2003

I don't know if this has come up with anyone "yet", but I recently had a SERVICE 4WD error message on my display. The selector buttons all went out and I was unable to shift out of 2WD (not that I need to yet). I took it to my dealer who found an error code B2725 which indicated an error in the transfer case mode switch. The switch was replaced, under warantee, and all is better.

Hotair · October 16, 2003

I had That problem.... took it in for service and they had to replace the module.

c5vetteman · October 16, 2003

Common problem. If I remeber right, mine went out before 36K miles. I now have over 64K. Wonder if it will go out again?

DSZ71 · October 16, 2003

Yup me too, had it replaced. I think GM put that problem on the list of TSB (techical services bulletin).

richscorvettes · October 20, 2003

I had the "Service 4WD" message appear on a trip this summer. The dash light switched from 2WD to 4WD while moving! We stopped at a dealer in Indianapolis and they found a tech bulletin (#03-04-21-001C) from 6/24/03. The DTC's on this one were C0327or P0836 and/or P0500.

It called for replacing the encoder motor sensor, reprogramming the TCCM and inspecting the front drive axle engagement sleeves. My local dealer ordered the parts and replaced all the items called for. Thus far it appears to have corrected the problem.

Rich Lagasse