AutoDiag

P0600

Serial Communication Link

Moderate· Fix soonProfessionalPowertrainGeneric, all makes

What it means

The ECU has lost communication with another module (or an internal processor) over its serial data link.

Is it safe to drive?

Varies. Some cars run normally; others go into limp mode.

Symptoms

  • Check engine light on
  • Several other module codes
  • Possible limp mode

Probable causes

Most likely first

  1. 1Poor battery or ground connection
  2. 2Communication wiring fault
  3. 3Failing ECU

How to diagnose it

Work through these in order before buying parts

  1. 1Record the code and its freeze frame data (speed, load, temperature when it set), then clear it and see if it comes back.
  2. 2Check battery voltage and the main ground connections.
  3. 3Scan all modules for communication codes.
  4. 4Check for technical service bulletins (TSBs) or software updates for your make and model; some codes have known factory fixes.

Common fixes

  • Repair power or ground connections
  • Repair data link wiring
  • Replace or reprogram the ECU

This information is general guidance for all makes. Exact causes, specifications and procedures vary by vehicle, so confirm with your service manual or a qualified mechanic before replacing parts.