OBD-II code · Network
U0291 Lost Communication With Gear Shift Control Module B
The vehicle bus reports loss of communication with gear shift control module B. Shift-by-wire requests for park/reverse/drive coordinated through this node are no longer answered.
Is it safe to drive with U0291?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyBus wiring open or shorted
- PossibleModule without power or ground
- PossibleModule failed
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
- 1–4 h
- Emissions test
- Usually unaffected
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Gear Shift Control Module B, Vehicle Bus Wiring
Related codes
- U028ELost Communication With Active Aerodynamic Feature Control Module B
- U028FLost Communication With Active Aerodynamic Feature Control Module C
- U0290Lost Communication With Active Aerodynamic Feature Control Module D
- U0292Lost Communication With Drive Motor Control Module B
- U0293Lost Communication with Hybrid Vehicle Control System
- U0294Lost Communication with Powertrain Control Module B
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.