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P0787 Shift Timing Solenoid A low

The OBD2 code P0787 indicates a problem with the shift timing solenoid A, specifically that it is operating at a low voltage or is malfunctioning, which can affect the transmission's shifting performance

Definition

The OBD2 code P0787 indicates a problem with the shift timing solenoid A, specifically that it is operating at a low voltage or is malfunctioning, which can affect the transmission's shifting performance

Common causes

  • Faulty shift timing solenoid A
  • Low transmission fluid level
  • Contaminated transmission fluid
  • Wiring issues or damaged connectors
  • Faulty transmission control module (TCM)
  • Internal transmission problems
  • Poor electrical connections

Common misdiagnoses

  • Transmission fluid issues
  • Faulty transmission control module (TCM)
  • Wiring or connector problems
  • Faulty shift solenoid
  • Transmission valve body issues
  • Internal transmission damage
  • Engine control module (ECM) problems
  • Incorrectly installed or damaged transmission filter

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

    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 Level and Condition

    Low or dirty transmission fluid can cause shifting issues. Check the fluid level and condition. If the fluid is low, top it off with the correct type of transmission fluid. If it is dirty or burnt, consider a transmission fluid change

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

    Ensure that the TCM is functioning properly. Check for any signs of damage or corrosion. If necessary, reprogram or replace the TCM

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

  8. 8. Consult a Professional

    If the issue persists after performing these steps, it may be best to consult a professional mechanic or transmission specialist for further diagnosis and repair. By following these steps, you can systematically identify and address the underlying issue causing the P0787 code