DTC codes / U01xx · Lost communication with a control module / U01A7
U01A7 is a generic communication fault indicating that the vehicle's main control modules have stopped receiving valid controller area network (CAN) messages from the hybrid or electric vehicle battery interface control module designated H. The computer detects this when the expected periodic data frames from that module fail to arrive within a defined time window, setting the code and often illuminating the warning light.
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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