AutoDiag

P0606

Control Module Processor

High· Fix promptlyProfessionalPowertrainGeneric, all makes

What it means

The ECU has detected an internal fault in its own processor.

Is it safe to drive?

Not recommended. The car may go into limp mode or stall.

Symptoms

  • Check engine light on
  • Limp mode
  • Stalling or no start

Probable causes

Most likely first

  1. 1Internal ECU fault
  2. 2Poor ECU power or ground
  3. 3Outdated software

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 ECU power and grounds under load.
  3. 3Check for software updates.
  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 grounds
  • Update the ECU software
  • Replace and program 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.