OBD-II code · Network
U01B5 Lost Communication With Catalyst Heater Control Module
ECU lost communication with the electric catalyst heater control module (helps cat reach light-off faster).
Is it safe to drive with U01B5?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
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
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Catalyst Heater Module, Can Bus
Related codes
- U01B2Lost Communication With Planetary Gear Set Control Module
- U01B3Lost Communication With Brake Blending Actuator
- U01B4Lost Communication With Brake System Control Module B
- U01B6Lost Communication With Fuel Heater Control Module
- U01B7Lost Communication With Switch Input Module A
- U01B8Lost Communication With Switch Input Module B
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.