Powertrain, generic · Computer and auxiliary outputs

P0606 Control Module Processor

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0606 means the module doubts the integrity of its own processor. Checks include a question-and-answer game between main and monitoring processor (GM: new seed via SPI within 450 ms; Ford: 'quizzer' level 3), arithmetic unit and register tests, stack overflow, the order in which safety-critical software runs, and the internal voltage supply (Ford diesel: 5 V rail outside 4.7–5.3 V). Because it belongs to the electronic throttle safety concept, the module usually reacts with a failure mode – reduced power, RPM limit or throttle default position – and the lamp in the first trip. Many cases are software issues fixed by reprogramming (Chrysler 3.6 L 2014, VW Routan, GM brake module 2024), so check bulletins before replacing hardware. The code alone does not say which module set it – the scan tool shows whether it is the engine, transmission, brake or body module.

Likely causes

Faulty module software (update available)
Low voltage, voltage dips or a poor ground or supply at the module
Internal hardware defect (processor, voltage regulator, output stage chip)
Short on a 5 V sensor reference loading the internal supply

Symptoms

  • Check engine light, at Ford also the wrench lamp
  • Limp mode with reduced power or RPM limit
  • Poor throttle response
  • Rarely stalling or no start
  • Often together with voltage codes P0562/P0563

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,500
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

What to check first

  1. Check power and grounds
  2. Check for updates
  3. Replace module if confirmed

Parts involved

engine control modulecontrol module power supplycontrol module ground

Related codes

P0600P0607P060AP060BP060CP0562

References: law.cornell.edu, gsi.ext.gm.com, fordservicecontent.com, fordservicecontent.com.