OBD Guide
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P1766

CAN Communication Bus Off

P1766 is an OBD-II diagnostic trouble code meaning: CAN Communication Bus Off. Common causes: broken or damaged can bus wires, short circuit in can circuit. Estimated repair cost: $6–56.

Severity
🔴 High
Can 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

  1. Check the integrity of the CAN bus wiring
  2. Check the voltage on the CAN bus (should be about 2.5V)
  3. Check connectors and contacts for corrosion
  4. Disable the modules one by one to identify the faulty one.
  5. If necessary, replace damaged wires or connectors

Related codes

P1767P1768U0001

Error P1766 by Vehicle Brand

FordLincolnMercuryVolkswagen

FAQ

What does the P1766 code mean?

P1766 is an OBD-II diagnostic trouble code that indicates: CAN Communication Bus Off

What causes a P1766 error code?

The most common causes of P1766 include: 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.

How do I fix a P1766 diagnostic trouble code?

To fix P1766: 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. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1766?

Limited driving only, diagnose soon

How much does it cost to fix P1766?

The estimated repair cost for P1766 is $6–56. Actual cost depends on your vehicle, location, and labor rates.

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