WOMS
P code powertrain High severity

P0788 Shift Timing Solenoid A High

The OBD2 code P0788 indicates that there is a problem with the shift timing solenoid A, specifically that it is operating at a higher than expected voltage or resistance, which can affect the transmission's shifting...

Definition

The OBD2 code P0788 indicates that there is a problem with the shift timing solenoid A, specifically that it is operating at a higher than expected voltage or resistance, which can affect the transmission's shifting performance

Common causes

  • Faulty shift timing solenoid A
  • Wiring issues (shorts or open circuits)
  • Poor electrical connections
  • Transmission control module (TCM) malfunction
  • Low transmission fluid level
  • Contaminated transmission fluid
  • Faulty transmission valve body
  • Internal transmission issues

Common misdiagnoses

  • Transmission fluid issues
  • Faulty transmission control module (TCM)
  • Wiring or connector problems
  • Other solenoid failures
  • Internal transmission damage
  • Incorrect transmission fluid type
  • Engine control module (ECM) issues
  • Valve body problems

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 help identify if there are related issues that need to be addressed

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring and connectors associated with the shift solenoid A. Look for signs of damage, corrosion, or loose connections. Repair or replace any damaged components

  3. 3. Test the Shift Solenoid

    Use a multimeter to test the resistance of the shift solenoid A. Compare the readings to the specifications provided in the vehicle's service manual. If the solenoid is out of spec, it may need to be replaced

  4. 4. Check Transmission Fluid

    Ensure that the transmission fluid is at the correct level and in good condition. Low or dirty fluid can cause shifting issues. If the fluid is dirty, consider performing a transmission fluid change

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

    The TCM controls the operation of the shift solenoids. Check for any signs of damage or malfunction. If necessary, test the TCM for proper operation

  6. 6. Check for Mechanical Issues

    Inspect the transmission for any mechanical problems that could affect shifting, such as worn clutches or bands. A transmission specialist may be needed for a thorough inspection

  7. 7. Clear Codes and Test Drive

    After performing any repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code returns. Monitor the transmission's shifting behavior during the drive

  8. 8. Consult a Professional

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or transmission specialist for further diagnosis and repair. By following these steps, you can systematically identify and address the cause of the P0788 code