High Speed CAN Communication Bus
Communication issue on the high-speed CAN bus.
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What it means (plain English)
The computer can't talk properly to other modules through the high-speed CAN bus, which can mess up a lot of systems in the vehicle.
What the computer is actually seeing
The data packets sent and received over the CAN bus are missing or corrupted, typically indicated by an abnormal voltage level (0 volts instead of the expected 2.5V to 3.5V) when checking the bus status.
What a healthy reading looks like
Expected bus voltage should range between 2.5V to 3.5V with a stable communication frequency around 500kbps for high-speed CAN.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect wiring and connectors for physical damage between the ECU and other modules. Repair any issues found, then retest the system.
- 22. Check the voltage on the CAN bus wires. You should see 2.5V to 3.5V. If not, there’s a wiring issue or a module failure.
- 33. Disconnect each module one at a time while monitoring the CAN bus voltage. If the voltage returns to normal with a particular module disconnected, that module may be faulty.
- 44. Use a scan tool to check for other stored DTCs related to the modules on the CAN bus. Address those codes as needed before retesting.
Common causes
- Loose or damaged wiring on the CAN bus
- Faulty CAN bus connector
- One of the modules on the bus failing or malfunctioning
- Interference from aftermarket devices
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code present?
It's a moderate severity code, so while the car may still run, you could lose functionality of some systems, making it less safe.
Will this code come back after clearing it?
If the underlying communication issue isn't fixed, the code will likely return after clearing.
Why does this code appear with other codes?
This code often appears alongside others indicating issues with modules that are supposed to communicate over the CAN bus.
Working a real vehicle right now?
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