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P0686: ECM/PCM Power Relay Control Circuit Low

Severity
Medium
System
Computer and Output Circuits

What Does P0686 Mean?

P0686 is a diagnostic trouble code indicating: ECM/PCM Power Relay Control Circuit Low. This code relates to the computer and output circuits system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P0686

Common Causes

Frequently Asked Questions

What does P0686 mean?
P0686 indicates: ECM/PCM Power Relay Control Circuit Low. The vehicle's computer has detected that the ECM/PCM Power Relay is not operating within its expected parameters and stored this diagnostic trouble code.
Can I drive with code P0686?
You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P0686 for extended periods may cause additional problems.
How much does it cost to fix P0686?
Repair costs for P0686 typically range from $20 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

  • 🔧 Repair broken wire or restore ground in ECM/PCM Power Relay circuit
  • 🔧 Clean and secure ECM/PCM Power Relay connector and ground points
  • 🔧 Replace failed ECM/PCM Power Relay
  1. 1
    Find your vehicle above

    Click your make and model for real owner reports and common causes specific to your vehicle.

  2. 2
    Check for recalls

    Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.

  3. 3
    Get a professional diagnosis

    A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

Related Codes

P0600 Serial Communication Link P0601 Internal Control Module Memory Checksum Error P0602 Control Module Programming Error P0603 Internal Control Module Keep Alive Memory (KAM) Error P0604 Internal Control Module RAM Error P0605 Internal Control Module Read Only Memory (ROM) Error P0606 Control Module Processor P0607 Control Module Performance P0608 Control Module VSS Output A P0609 Control Module VSS Output B