WOMS
P code powertrain High severity

P0990 Transmission Fluid Pressure Sensor/Switch "E" Circuit High

The OBD2 code P0990 indicates that the transmission fluid pressure sensor or switch "E" is reporting a high voltage signal, which may suggest a malfunction in the sensor, wiring, or the transmission control system

Definition

The OBD2 code P0990 indicates that the transmission fluid pressure sensor or switch "E" is reporting a high voltage signal, which may suggest a malfunction in the sensor, wiring, or the transmission control system

Common causes

  • Faulty transmission fluid pressure sensor
  • Wiring issues (short circuit or open circuit)
  • Poor electrical connections
  • Transmission control module (TCM) malfunction
  • Low transmission fluid level
  • Contaminated transmission fluid
  • Faulty transmission solenoid
  • Internal transmission problems

Common misdiagnoses

  • Faulty transmission fluid pressure sensor
  • Wiring issues or short circuits
  • Transmission control module (TCM) failure
  • Low transmission fluid level
  • Faulty transmission solenoids
  • Internal transmission problems
  • Engine control module (ECM) issues
  • Incorrect transmission fluid type or condition

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are other issues affecting the transmission

  2. 2. Inspect the Wiring and Connectors

    Visual Inspection: Check the wiring harness and connectors associated with the Transmission Fluid Pressure Sensor. Look for signs of damage, corrosion, or loose connections

  3. 3. Connector Condition

    Ensure that the connectors are securely attached and free from dirt or moisture

  4. 4. Test the Transmission Fluid Pressure Sensor

    Resistance Check: Use a multimeter to measure the resistance of the sensor. Compare the readings to the specifications provided in the vehicle’s service manual

  5. 5. Voltage Check

    With the ignition on (engine off), check the voltage at the sensor connector. It should match the specifications in the service manual

  6. 6. Check Transmission Fluid Level and Condition

    Fluid Level: Ensure that the transmission fluid is at the correct level. Low fluid levels can cause erratic sensor readings

  7. 7. Fluid Condition

    Inspect the fluid for contamination or burning. If the fluid is dirty or smells burnt, it may need to be changed

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

    Software Updates: Check if there are any software updates available for the TCM that may address known issues

  9. 9. TCM Functionality

    If other components are functioning normally, consider testing or replacing the TCM if it is suspected to be faulty

  10. 10. Check for Ground Issues

    Ensure that the ground connections for the transmission and the sensor are secure and free from corrosion. Poor grounding can lead to erroneous readings

  11. 11. Perform a System Reset

    After addressing any issues found, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  12. 12. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to the P0990 code for your specific vehicle make and model. Manufacturers may have issued guidance on common issues and fixes

  13. 13. Professional Diagnosis

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has access to advanced diagnostic tools and equipment.Conclusion By following these troubleshooting steps, you can systematically identify and address the cause of the P0990 code. Always refer to the vehicle’s service manual for specific details and specifications related to your vehicle