OBD-II code · Network
U04B6 Invalid Data Received From Catalyst Heater Control Module
A receiving module detected implausible data from the catalyst heater control module (electrically heated catalyst, EHC). Heater current/voltage or temperature values fail plausibility checks and are rejected; emissions warm-up cannot be guaranteed.
Is it safe to drive with U04B6?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyModule internal fault or sensor input drift
- PossibleSoftware version mismatch after replacement
- 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
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Catalyst Heater Module
Related codes
- U04B3Invalid Data Received From Planetary Gear Set Control Module
- U04B4Invalid Data Received From Brake Blending Actuator
- U04B5Invalid Data Received From Brake System Control Module B
- U04BAInvalid Data Received From Switch Input Module A
- U04BBInvalid Data Received From Switch Input Module B
- U04BCInvalid Data Received From Switch Input Module C
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.