What does code U04B6 mean?

Q: What does code U04B6 mean?

Invalid Data Received From Catalyst Heater Control Module. U04B6 means the vehicle's main control module (often the engine control module, or ECM) is not receiving valid data over the controller area network (CAN) from the catalyst heater control module. The ECM has detected that the messages it expects from the catalyst heater module are missing, corrupted, or implausible, so it flags a communication fault rather than a direct heater circuit failure.

DTC codes / U04xx · Invalid data received from a module / U04B6

U04B6Invalid Data Received From Catalyst Heater Control Module

U04B6 means the vehicle's main control module (often the engine control module, or ECM) is not receiving valid data over the controller area network (CAN) from the catalyst heater control module. The ECM has detected that the messages it expects from the catalyst heater module are missing, corrupted, or implausible, so it flags a communication fault rather than a direct heater circuit failure.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaInvalid data received from a module

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.