This code indicates the high-speed Controller Area Network (CAN) bus High line is reading battery voltage or is stuck in a dominant state, disrupting communication between control modules. The CAN High circuit normally carries data via voltage fluctuations around 2.5–3.5 volts, so a constant high voltage prevents message transmission. This typically results from a short to power in the wiring harness or an internal module fault pulling the bus high.
Wiring harness chafed, melted, or damaged by rodents or abrasion, causing the CAN High wire to contact battery voltage, ignition power, or another powered circuit.
Moisture intrusion at junction connectors, water ingress at module plugs, or terminal fretting creates a conductive path between CAN High and power circuits.
A specific module such as the ABS, airbag, or body control module has an internal short circuit pulling the CAN High line to power voltage, effectively biasing the entire bus.
While less common for this specific code, damaged or missing termination resistors can cause voltage anomalies that trigger a false "High" reading on the bus.
Rare; the PCM itself may have an internal fault shorting the CAN transceiver, but this is statistically unlikely compared to wiring issues and should only be considered after all other causes are eliminated.
No. Critical systems may stop communicating without warning, potentially disabling safety features like ABS, airbags, or steering assist while driving.
Almost never. This code almost always stems from wiring shorts or a different control module failing; replacing the PCM is usually unnecessary and costly.
It is the vehicle's high-speed data network that allows modules (engine, transmission, brakes) to share information; "CAN High" is one of the two differential signal wires that carry this data.
Usually due to recent wiring damage from rodent chewing, accident repair, or harness abrasion against metal brackets that finally wore through insulation.