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DTC codes / U02xx · Lost communication with a control module / U029A

U029ALost Communication With Hybrid/EV Battery Pack Sensor Module

U029A is a generic network communication code indicating that the primary control module has lost contact with the Hybrid/EV Battery Pack Sensor Module over the vehicle's high-speed data bus. The computer has detected a complete absence of expected messages from that sensor module for a calibrated time period, not a performance fault within the battery itself.

SystemNetwork
Code typeGeneric (all makes)
SeverityHigh
Fix difficultyProfessional
AreaLost communication with a control 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.

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