Lost Communication With Gear Shift Module
The U0103 code means the vehicle's onboard diagnostic system has detected: Lost Communication With Gear Shift Module. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $100 - $600 (parts and labor)
Network codes mean modules are not communicating. You need a scanner that reads all systems to find the problem.
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Common Symptoms
- Check Engine Light illuminated
- Shift indicator malfunction
- Cannot shift out of Park
- Gear selection issues
Probable Causes (Ranked by Likelihood)
- Failed gear shift module Very High
- CAN bus wiring issue to shift module High
- Corroded shift module connector Moderate
- Shift module power supply loss Low
Step-by-Step Diagnostic Procedure
-
Check gear shift module power and ground
-
Inspect module connector for damage
-
Check CAN bus communication to the shift module
-
Verify shift interlock solenoid operation
-
Replace gear shift module if needed
Frequently Asked Questions
Can I drive with code U0103?
Drive short distances only. Lost communication codes indicate a module has stopped communicating on the vehicle network. The affected system may not function correctly.
What causes U0103?
The most common cause is a failed module or a wiring issue in the CAN bus network. Failed gear shift module is the most likely cause. Power supply, ground, and connector issues should be checked before replacing any module.
Is U0103 expensive to fix?
Repair costs range from $100 - $600 (parts and labor). Wiring repairs are on the lower end, while module replacement is on the higher end. The module may also need to be programmed after replacement.
Sources
This page is built from documented references. Verify against your own service info before repair work.
U0103 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
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