P0987 Transmission Fluid Pressure Sensor/Switch "E" Circuit

Definition

Common causes

• Faulty transmission fluid pressure sensor
• Wiring issues (shorts, opens, or corrosion)
• Poor electrical connections
• Transmission fluid leaks
• Low transmission fluid level
• Faulty transmission control module (TCM)
• Internal transmission problems

Common misdiagnoses

• Faulty transmission fluid pressure sensor
• Wiring issues or short circuits in the sensor circuit
• Transmission control module (TCM) failure
• Low transmission fluid level or quality
• Faulty transmission solenoids
• Internal transmission problems
• Engine control module (ECM) issues
• Incorrectly installed or damaged transmission components

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 multiple issues

2. 2. Inspect the Transmission Fluid

   Fluid Level: Ensure that the transmission fluid is at the correct level. Low fluid can cause pressure issues

3. 3. Fluid Condition

   Check the condition of the fluid. If it is dirty, burnt, or has a strange odor, it may need to be changed

4. 4. Visual Inspection

   Wiring and Connectors: Inspect the wiring and connectors related to the Transmission Fluid Pressure Sensor/Switch "E". Look for signs of damage, corrosion, or loose connections

5. 5. Sensor Condition

   Check the physical condition of the transmission fluid pressure sensor. If it appears damaged, it may need to be replaced

6. 6. Test the Sensor

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

7. 7. Voltage Check

   With the ignition on (engine off), check the voltage at the sensor connector. Ensure it is receiving the correct voltage as specified in the service manual

8. 8. Check for Short Circuits or Open Circuits

   Use a multimeter to check for continuity in the wiring harness. Look for any shorts to ground or open circuits that could affect the sensor's operation

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

   If the sensor and wiring are in good condition, the issue may lie with the Transmission Control Module. Check for any software updates or known issues with the TCM

10. 10. 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

11. 11. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the P0987 code for your specific vehicle make and model. Manufacturers may have issued guidance on common issues and fixes

12. 12. Professional Diagnosis

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or transmission specialist. They may have access to advanced diagnostic tools and experience with specific vehicle issues.Conclusion By following these troubleshooting steps, you can systematically identify and address the cause of the P0987 code. Always refer to the vehicle’s service manual for specific procedures and specifications related to your vehicle