CAN Time-Out

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📖 YOUCANIC Automotive Glossary

CAN Time-Out occurs when a module fails to receive an expected message from another module within a specified time window. Modules periodically broadcast status messages at defined intervals — other modules set timers expecting each message within a timeframe. When the timer expires without receiving the message, a time-out fault and U-code DTC is recorded: U0100 (Lost Communication with ECM), U0101 (TCM), U0121 (ABS), etc.

CAN Time-Out is caused by the transmitting module losing power/ground, CAN wiring damage, the transmitting module crashing or going Bus Off, a gateway failure, or the module being physically disconnected. When multiple U-codes from different modules all point to the same missing module, the problem is with that one module — not the others reporting the fault. Start by checking power, ground, and CAN wiring at the non-communicating module.

Synonyms:
Communication Time-Out, Message Time-Out
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