OBD Guide

U0003

High Speed CAN Communication Bus (+) Open

Severity: HIGH

Symptoms

  • Check Engine light comes on
  • Incorrect operation of various vehicle systems
  • Lost connection with some modules
  • Problems starting the engine
  • Dashboard malfunctions

Causes

  • Broken wire in the CAN bus (+)
  • Corrosion of contacts in connectors
  • Wiring harness damage
  • Fault in one of the modules connected to the bus
  • Problems with CAN bus power supply

How to Fix

  1. Check the integrity of the CAN bus wires (+)
  2. Inspect connectors for corrosion or damage
  3. Check resistance and continuity
  4. Diagnose the operation of modules connected to the bus
  5. If necessary, replace damaged wires or connectors

Related codes