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TorqueMech OBD Code Guide

P0685 - ECM/PCM Power Relay Circuit Open

ECM/PCM power relay circuit open.

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Code Overview

ECM/PCM power relay circuit open.

Common Causes

  • Component failure
  • Wiring/connectors issue
  • System condition causing fault

Diagnostic Steps

  1. Check for related codes and freeze-frame data
  2. Inspect wiring/connectors for damage/corrosion
  3. Verify sensor readings on a scan tool if available
  4. Clear code and road test to confirm fix

Likely Repairs & Cost Guides

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Related OBD Codes

Browse nearby codes when systems overlap.

P0684
Glow Plug Control Module to PCM Communication Circuit Range/Performance
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P0686
ECM/PCM Power Relay Control Circuit Low
Open code guide →
P0683
Glow Plug Control Module to PCM Communication Circuit
Open code guide →
P0687
ECM/PCM Power Relay Control Circuit High
Open code guide →
P0682
Cylinder 12 Glow Plug Circuit
Open code guide →

Next Steps

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