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P0749 Pressure Control Solenoid A Intermittent

The OBD2 code P0749 indicates that there is an intermittent issue with the pressure control solenoid A in the transmission system, which affects the transmission's ability to regulate fluid pressure properly

Definition

The OBD2 code P0749 indicates that there is an intermittent issue with the pressure control solenoid A in the transmission system, which affects the transmission's ability to regulate fluid pressure properly

Common causes

  • Faulty pressure control solenoid A
  • Wiring issues (shorts, opens, or corrosion)
  • Poor electrical connections
  • Transmission fluid issues (low level, contamination)
  • Faulty transmission control module (TCM)
  • Internal transmission problems
  • Faulty engine control module (ECM)

Common misdiagnoses

  • Transmission fluid issues
  • Faulty transmission control module (TCM)
  • Wiring or connector problems
  • Other solenoid failures
  • Torque converter issues
  • Valve body problems
  • Engine control module (ECM) faults
  • Mechanical transmission failures

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

    Examine the wiring and connectors leading to the pressure control solenoid. Look for signs of damage, corrosion, or loose connections. Repair or replace any damaged components

  3. 3. Test the Pressure Control Solenoid

    Use a multimeter to test the resistance of the solenoid. Compare the readings to the specifications in the vehicle’s service manual. If the resistance is outside the specified range, the solenoid may need to be replaced

  4. 4. Check Transmission Fluid Level and Condition

    Low or dirty transmission fluid can cause shifting issues and affect solenoid operation. Check the fluid level and condition; if it’s low, top it off with the correct type of fluid. If it’s dirty or burnt, consider a transmission fluid change

  5. 5. Inspect the Transmission Filter

    A clogged transmission filter can restrict fluid flow and affect solenoid performance. If the filter is dirty, replace it

  6. 6. Test the Transmission Control Module (TCM)

    The TCM controls the operation of the solenoids. If there’s a fault in the TCM, it may not send the correct signals to the solenoid. Testing or reprogramming the TCM may be necessary

  7. 7. Check for Mechanical Issues

    Inspect the transmission for any mechanical problems that could affect solenoid operation, such as sticking valves or internal leaks

  8. 8. Perform a Road Test

    After addressing any issues found, take the vehicle for a test drive to see if the code reappears. Monitor the transmission performance during the drive

  9. 9. Clear the Codes

    After repairs, clear the trouble codes using the OBD-II scanner and see if the code returns after a few driving cycles

  10. 10. Consult a Professional

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or transmission specialist for further diagnosis. Always refer to the specific service manual for your vehicle for detailed procedures and specifications