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P code powertrain High severity

P0682 ECM/PCM Power Relay Control Circuit Low

The OBD2 code P0682 indicates a problem with the ECM/PCM power relay control circuit, specifically that the circuit is reading a low voltage or is not functioning properly

Definition

The OBD2 code P0682 indicates a problem with the ECM/PCM power relay control circuit, specifically that the circuit is reading a low voltage or is not functioning properly

Common causes

  • Faulty ECM/PCM
  • Bad power relay
  • Open or shorted wiring in the control circuit
  • Poor ground connection
  • Blown fuse
  • Corroded connectors
  • Faulty ignition switch

Common misdiagnoses

  • Faulty ECM/PCM
  • Bad power relay
  • Wiring issues or shorts
  • Battery problems
  • Ignition switch failure
  • Ground connection issues
  • Faulty fuses
  • Corroded connectors

Troubleshooting steps

  1. 1. Check the Battery and Connections

    Inspect the Battery: Ensure the battery is fully charged and in good condition

  2. 2. Check Battery Connections

    Look for corrosion or loose connections at the battery terminals and ground points

  3. 3. Inspect the Fuses

    Check Fuses: Locate and inspect the fuses related to the ECM/PCM and the power relay. Replace any blown fuses

  4. 4. Examine the Power Relay

    Test the Relay: Remove the ECM/PCM power relay and test it using a multimeter or swap it with a known good relay to see if the issue persists

  5. 5. Check Relay Connections

    Ensure that the relay terminals are clean and free of corrosion

  6. 6. Inspect Wiring and Connectors

    Visual Inspection: Look for damaged, frayed, or corroded wiring in the circuit leading to the ECM/PCM and the power relay

  7. 7. Check Connectors

    Ensure that all connectors are securely attached and free of corrosion or damage

  8. 8. Test the ECM/PCM

    Check for Ground: Ensure that the ECM/PCM has a good ground connection

  9. 9. Voltage Check

    Use a multimeter to check for proper voltage at the ECM/PCM power input. It should typically be around 12V with the ignition on

  10. 10. Scan for Other Codes

    Check for any additional trouble codes that may provide more context to the issue

  11. 11. Check for Short Circuits

    Inspect for Shorts: Use a multimeter to check for shorts to ground or power in the wiring harness related to the ECM/PCM power relay circuit

  12. 12. Perform a Continuity Test

    Test Continuity: With the ignition off, perform a continuity test on the wiring between the relay and the ECM/PCM to ensure there are no breaks in the circuit

  13. 13. Check for Software Updates

    ECM/PCM Updates: Check if there are any software updates available for the ECM/PCM that may address known issues

  14. 14. Consult Repair Manual

    Refer to Service Manual: Consult the vehicle’s service manual for specific wiring diagrams and troubleshooting procedures related to the P0682 code

  15. 15. Professional Diagnosis

    If the issue persists after performing these steps, consider seeking help from a professional mechanic or technician who has access to advanced diagnostic tools. By following these steps, you should be able to identify and resolve the issue related to the P0682 code. Always remember to take necessary safety precautions when working on a vehicle's electrical system