OBD-II code · Network
U012B Lost Communication With Chassis Control Module B
ECU lost CAN communication with chassis control module B (vehicle dynamics). A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
Is it safe to drive with U012B?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyModule 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
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–5 h
- Emissions test
- Usually unaffected
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Chassis Module B, Can Bus
Related codes
- U012ALost Communication With Chassis Control Module A
- U0128Lost Communication with Park Brake Control Module
- U0129Lost Communication with Brake System Control Module
- U012CLost Communication With Active Vibration Control Module
- U012DLost Communication With Generator A Control Module
- U012ELost Communication With Camshaft Position Control Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.