OBD-II code · Network
U0103 Lost Communication with Gear Shift Module
The Gear Shift Module has stopped transmitting on the vehicle data bus, so other control units no longer receive its messages. Shift-by-wire gear selection can fail and leave the transmission in a default position. Typical causes are loss of power or ground at the module, an open or shorted CAN/LIN bus wire, a connector fault, or an internal module failure.
Is it safe to drive with U0103?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyShift module unpowered
- PossibleCAN wiring to shift module broken
- Less likelyGateway module routing CAN messages incorrectly
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–5 h
- Emissions test
- Usually unaffected
- Parts involved
- Gear Shift Module, Can Bus Wiring
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.