OBD-II code · Network
U034B Software Incompatibility With Brake Booster Control
A module reports a software version mismatch with the brake booster control module — typically after replacing one of the modules without programming the new unit to match the rest of the network.
Is it safe to drive with U034B?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyModule replaced without programming
- PossibleWrong part number for the vehicle
- 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
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–2 h
- Emissions test
- Usually unaffected
- Parts involved
- Brake Booster Module
Related codes
- U0348Software Incompatibility With Hybrid/EV Battery Interface Control Module O
- U0349Software Incompatibility With Hybrid/EV Battery Interface Control Module P
- U034ASoftware Incompatibility With Engine Disconnect Clutch
- U034CSoftware Incompatibility With Battery Energy Control Module C
- U034DSoftware Incompatibility With Vehicle Thermal Management Control Module
- U034ESoftware Incompatibility With Active Grille Air Shutter Module A
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.