Transmission Fluid Pressure Sensor/Switch "E" Circuit
P0987 indicates a fault in the transmission fluid pressure sensor/switch E circuit, which monitors transmission hydraulic pressure for proper shifting control. This electrical circuit fault prevents the transmission control module from accurately reading pressure, potentially causing erratic shifting or limp mode operation.
What You Might Notice
- Transmission shifting erratically or harshly
- Vehicle entering limp mode or reduced power mode
- Check engine light illuminated
- Delayed gear engagement or delayed shifts
- Transmission slipping or flaring during acceleration
Most Common Causes
- 1
Open circuit in sensor wiring
A broken or disconnected wire in the transmission fluid pressure sensor E circuit prevents signal transmission to the TCM. This is the most common electrical cause.
- 2
Transmission Fluid Pressure Sensor E failure
Internal sensor malfunction or mechanical failure causes the sensor to stop responding or provide incorrect readings to the transmission control module.
- 3
Short to voltage or ground in signal circuit
Damaged wire insulation creates a short circuit, pulling the sensor signal to battery voltage or ground, preventing proper signal recognition by the TCM.
- 4
Internal transmission mechanical issue
Severe transmission problems can cause pressure fluctuations that exceed sensor limits or damage the sensor, though this is less common than electrical faults.
How to Diagnose It
- 1
Check Open circuit in sensor wiring — A broken or disconnected wire in the transmission fluid pressure sensor E circuit prevents signal transmission to the TCM. This is the most common electrical cause.
- 2
Check Transmission Fluid Pressure Sensor E failure — Internal sensor malfunction or mechanical failure causes the sensor to stop responding or provide incorrect readings to the transmission control module.
- 3
Check Short to voltage or ground in signal circuit — Damaged wire insulation creates a short circuit, pulling the sensor signal to battery voltage or ground, preventing proper signal recognition by the TCM.
- 4
Check Internal transmission mechanical issue — Severe transmission problems can cause pressure fluctuations that exceed sensor limits or damage the sensor, though this is less common than electrical faults.
How to Fix It
- 1
Inspect and repair sensor wiring
Visually inspect the transmission fluid pressure sensor E harness and connector for corrosion, loose connections, or damaged wiring. Repair any broken wires or reconnect loose connectors.
- 2
Replace transmission fluid pressure sensor E
Remove the faulty sensor from the transmission case and install a new pressure sensor E, then clear the code and perform a test drive to verify transmission shifting.
- 3
Test TCM/PCM and reprogram if needed
Use a transmission diagnostic scanner to verify sensor readings and check for TCM faults. If TCM replacement is necessary, reprogramming with the vehicle VIN and transmission calibration is required.
- 4
Check transmission fluid and perform internal diagnosis
If electrical repairs do not resolve the code, inspect transmission fluid condition for contamination or low level, and perform internal pressure testing to rule out mechanical transmission failure.
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