WOMS
P code powertrain High severity

P1668 PCM - IDM Communications Error

The OBD2 code P1668 indicates a communication error between the Powertrain Control Module (PCM) and the Injector Driver Module (IDM), suggesting a problem in the data exchange between these components

Definition

The OBD2 code P1668 indicates a communication error between the Powertrain Control Module (PCM) and the Injector Driver Module (IDM), suggesting a problem in the data exchange between these components

Common causes

  • Faulty PCM (Powertrain Control Module)
  • Faulty IDM (Injector Driver Module)
  • Wiring issues or damaged connectors
  • Poor ground connections
  • Corroded terminals
  • Short circuits in the wiring harness
  • Software issues or programming errors
  • Electrical interference from other components
  • Failed sensors affecting communication
  • Battery or charging system problems

Common misdiagnoses

  • Faulty PCM (Powertrain Control Module)
  • Bad IDM (Injector Driver Module)
  • Wiring issues or shorts in the communication circuit
  • Faulty sensors (e.g., crankshaft or camshaft position sensors)
  • Corroded or loose connectors
  • Battery or charging system problems
  • Fuel system issues (e.g., low fuel pressure)
  • Injector problems or failures
  • Grounding issues in the electrical system
  • Software or firmware issues in the PCM or IDM

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Addressing other codes may help in diagnosing the P1668 code

  2. 2. Inspect Wiring and Connectors

    Visual Inspection: Check the wiring and connectors between the PCM and IDM for any signs of damage, corrosion, or loose connections

  3. 3. Repair or Replace

    Repair any damaged wires or connectors and ensure all connections are secure

  4. 4. Check Power and Ground

    Power Supply: Verify that the IDM is receiving the correct voltage from the PCM. Use a multimeter to check the voltage at the IDM connector

  5. 5. Ground Connections

    Ensure that all ground connections are clean and secure. A poor ground can cause communication issues

  6. 6. Test the IDM

    If possible, test the Injector Driver Module to ensure it is functioning correctly. This may involve using a scan tool or specialized equipment to check for proper operation

  7. 7. Inspect the PCM

    Check for Damage: Inspect the PCM for any signs of physical damage or corrosion

  8. 8. Reprogram or Replace

    If the PCM is suspected to be faulty, it may need to be reprogrammed or replaced

  9. 9. Check for Short Circuits

    Use a multimeter to check for short circuits in the wiring between the PCM and IDM. A short can cause communication errors

  10. 10. Look for Software Updates

    Check if there are any software updates available for the PCM or IDM. Sometimes, manufacturers release updates to fix known issues

  11. 11. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  12. 12. Seek Professional Help

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with your vehicle's specific systems. By following these troubleshooting steps, you should be able to identify and resolve the issue causing the P1668 code