Support Articles
Most Common Causes of CAN Communication Failures
1. Physical Layer Issues (Most Frequent)
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Incorrect terminal resistance
CAN bus needs 120Ω termination resistors at both ends.
Open, shorted, wrong value or missing termination causes signal reflection, distortion, and communication breakdown.
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Wiring faults
Broken wires, loose connectors, short circuit (CAN-H to CAN-L/GND), reversed CAN-H/CAN-L wiring.
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Bus line length & branch overlimit
Exceed maximum bus length, too long stub branches lead to signal attenuation and interference.
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Ground potential difference
Large GND voltage offset between ECUs damages transceivers or distorts differential signals.
2. Electrical Interference
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Strong electromagnetic interference (EMI) from high-power components: motors, inverters, relays, ignition systems.
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Poor shielding of CAN twisted-pair cable; shielding layer not grounded properly.
3. Hardware Component Failures
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CAN transceiver damage (most common hardware failure).
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ECU CAN controller chip failure.
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Damaged TVS diodes, filter capacitors on CAN interface.
4. Protocol & Configuration Mismatch
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Baud rate inconsistency between nodes (e.g., 250kbps vs 500kbps).
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Wrong node ID, duplicate CAN IDs.
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Incorrect CAN frame format (Standard ID / Extended ID mismatch).
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Bit timing register configuration errors.
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