WOMS
P code powertrain High severity

P0974 Shift Solenoid A Control Circuit High

The OBD2 code P0974 indicates a problem with the shift solenoid A control circuit, specifically that the circuit is reading a high voltage or resistance when it should not be

Definition

The OBD2 code P0974 indicates a problem with the shift solenoid A control circuit, specifically that the circuit is reading a high voltage or resistance when it should not be

Common causes

  • Faulty shift solenoid A
  • Wiring issues (short circuit or open circuit)
  • Poor electrical connections
  • Faulty transmission control module (TCM)
  • Low transmission fluid level
  • Contaminated transmission fluid
  • Internal transmission failure
  • Faulty PCM (Powertrain Control Module)
  • Corroded connectors

Common misdiagnoses

  • Faulty transmission control module (TCM)
  • Wiring issues or shorts in the harness
  • Faulty shift solenoid A
  • Low transmission fluid level or quality
  • Transmission fluid leaks
  • Faulty transmission valve body
  • Incorrectly diagnosed transmission failure
  • Issues with the engine control module (ECM)

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues

  2. 2. Inspect Wiring and Connectors

  3. 3. Visually inspect the wiring and connectors associated with the shift solenoid A. Look for signs of damage, corrosion, or loose connections

  4. 4. Ensure that the wiring harness is not pinched, frayed, or shorted to ground

  5. 5. Test the Shift Solenoid

  6. 6. Disconnect the shift solenoid connector and use a multimeter to test the solenoid's resistance. Compare the reading to the manufacturer's specifications

  7. 7. If the solenoid is out of spec, it may need to be replaced

  8. 8. Check the Power and Ground

  9. 9. With the ignition on (engine off), use a multimeter to check for voltage at the solenoid connector. You should see battery voltage

  10. 10. Check the ground circuit for continuity. If there is no ground, trace the wiring back to the control module

  11. 11. Inspect the Transmission Control Module (TCM)

  12. 12. If the wiring and solenoid are in good condition, the issue may lie within the TCM. Check for any signs of damage or corrosion

  13. 13. If possible, perform a software update or reset the TCM to see if that resolves the issue

  14. 14. Check for Fluid Issues

  15. 15. Ensure that the transmission fluid is at the correct level and in good condition. Low or dirty fluid can affect solenoid operation

  16. 16. If the fluid is contaminated, consider performing a transmission fluid change

  17. 17. Perform a Visual Inspection of the Transmission

  18. 18. Look for any signs of leaks or damage to the transmission that could affect solenoid operation

  19. 19. Clear the Codes and Test Drive

  20. 20. After performing any repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code returns

  21. 21. Consult a Professional

  22. 22. If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has access to advanced diagnostic tools and equipment. By following these steps, you should be able to identify the cause of the P0974 code and take appropriate action to resolve the issue