Diagnostic Resource Only
Note: Highway 71 Auto Parts provides this guide for diagnostic purposes only. We do not sell or service this specific module. We specialize exclusively in Engine (ECM/PCM), Transmission (TCM), and Body Control Modules (BCM). If your diagnostics point to an Engine or Transmission computer failure, contact us for a programmed replacement.
Stuck in 2WD? “Service 4WD” Light?
When the snow starts falling, you need your 4WD to work. If your buttons don’t light up or your truck won’t shift into 4-Lo, the TCCM is the first place to look.
What Does the TCCM Do?
The Transfer Case Control Module (TCCM) manages the electronic shift motor on your transfer case. It receives signals from your 4WD switch and verifies the shift was successful. In many GM and Dodge trucks, this module is located behind the dash or in the passenger kick panel.
👨🔧 Pro Tip: Check the Fuse First
“Before replacing the TCCM, check the ‘4WD’ or ‘TREC’ fuse in your engine bay fuse box. These modules often ‘hang’ or freeze. Removing the fuse for 60 seconds and putting it back in can sometimes ‘reset’ a dead TCCM.”
Signs of a Bad TCCM
- ✅ Dead Switch: No lights on the 2Hi/4Hi/4Lo buttons.
- ✅ Clicking but no Shift: The module is trying, but the internal relay is weak.
- ✅ Code C0327: Encoder Circuit Malfunction.
- ✅ Stuck in Neutral: The transfer case shifts to neutral and won’t come out, leaving the vehicle unable to move.
Programming Requirements
TCCMs are often year-specific and must be programmed with the correct tire size and axle ratio to ensure the Auto-4WD feature works correctly. Our TCCMs arrive pre-flashed for your VIN.