Network
generic / SAE
U01B5
Lost Communication With Catalyst Heater Control Module
ECU lost communication with the electric catalyst heater control module (helps cat reach light-off faster).
SystemNetwork
Typegeneric / SAE
GroupU0
Range / number1 / B5
Possible causes
- Module unpowered high
- Gateway module routing CAN messages incorrectly low
- CAN terminating resistor (120 Ω) drifted out of spec low
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
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 150–1500 €
- Estimated time: 1–5 h
- Component: catalyst heater module
- Component: can bus
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012