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P1749 Pressure Control Solenoid Failed Low

The OBD2 code P1749 indicates that the pressure control solenoid in the transmission is malfunctioning, specifically failing to provide the necessary pressure, which can affect shifting and overall transmission...

Definition

The OBD2 code P1749 indicates that the pressure control solenoid in the transmission is malfunctioning, specifically failing to provide the necessary pressure, which can affect shifting and overall transmission performance

Common causes

  • Faulty pressure control solenoid
  • Wiring issues (shorts or open circuits)
  • Poor electrical connections
  • Low transmission fluid level
  • Contaminated transmission fluid
  • Faulty transmission control module (TCM)
  • Internal transmission problems (e.g., worn components)

Common misdiagnoses

  • Transmission fluid issues
  • Faulty transmission control module (TCM)
  • Wiring or connector problems
  • Other solenoid failures
  • Torque converter issues
  • Valve body problems
  • Internal transmission damage

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 Transmission Fluid

    Check the transmission fluid level and condition. Low or dirty fluid can cause shifting issues and may affect the solenoid's operation. If the fluid is low, top it off with the manufacturer-recommended fluid. If it’s dirty or burnt, consider a transmission fluid change

  3. 3. Visual Inspection

    Inspect the wiring and connectors leading to the pressure control solenoid. Look for any signs of damage, corrosion, or loose connections that could affect the solenoid's operation

  4. 4. Test the Pressure Control Solenoid

    If accessible, test the solenoid's resistance using a multimeter. Compare the readings to the specifications provided in the vehicle's service manual. If the resistance is outside the specified range, the solenoid may need to be replaced

  5. 5. Check for Electrical Issues

    Use a multimeter to check for proper voltage and ground at the solenoid connector. If there is no voltage or ground, trace the wiring back to the transmission control module (TCM) or engine control module (ECM) to identify any breaks or shorts

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

    If the solenoid and wiring are in good condition, the issue may lie with the TCM. Check for any software updates or reprogramming that may be needed. In some cases, the TCM may need to be replaced

  7. 7. Perform a Transmission Fluid Pressure Test

    If you have the necessary tools, perform a pressure test to ensure that the transmission is operating within the specified pressure range. Low pressure can indicate internal transmission issues

  8. 8. Check for Mechanical Issues

    If all electrical components are functioning correctly, there may be internal mechanical issues within the transmission, such as worn clutches or valves. A professional transmission inspection may be necessary

  9. 9. Clear Codes and Test Drive

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

  10. 10. Consult a Professional

    If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic or transmission specialist for further diagnosis and repair. Always refer to the specific service manual for your vehicle for detailed procedures and specifications, as they can vary by make and model