P1766
CAN Communication Bus Off
Severity
🔴 HighCan you drive?
Limited driving only, diagnose soon
Approx. repair cost
$6–56 (est.)
Symptoms
- Check Engine light comes on
- Malfunctions of various vehicle systems
- Lost connection with diagnostic equipment
- Incorrect operation of the dashboard
- The car may go into emergency mode
Causes
- Broken or damaged CAN bus wires
- Short circuit in CAN circuit
- Fault in one of the modules connected to the bus
- Problems with power supply to CAN modules
- Corrosion of CAN bus connectors
How to Fix
- Check the integrity of the CAN bus wiring
- Check the voltage on the CAN bus (should be about 2.5V)
- Check connectors and contacts for corrosion
- Disable the modules one by one to identify the faulty one.
- If necessary, replace damaged wires or connectors