OBD-II code · Network
U0294 Lost Communication with Powertrain Control Module B
A second powertrain control module (e.g. on dual-engine, twin-turbo bank-specific or range-extender vehicles) has dropped off the network. Engine power is reduced or limp-home mode is forced.
Is it safe to drive with U0294?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyPCM B unpowered
- Less likelyGateway module routing CAN messages incorrectly
- Less likelyCAN terminating resistor (120 Ω) drifted out of spec
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
- 0.5–6 h
- Emissions test
- Usually unaffected
- Parts involved
- Powertrain Control Module, Can Bus Wiring
Related codes
- U0291Lost Communication With Gear Shift Control Module B
- U0292Lost Communication With Drive Motor Control Module B
- U0293Lost Communication with Hybrid Vehicle Control System
- U0295Lost Communication with Power Steering Control Module
- U0296Lost Communication With AC/DC Converter Control Module A
- U0297Lost Communication with Hybrid Powertrain Control Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.