Transmission Fluid Pressure Sensor/Switch "E" Circuit
Diagnostic trouble code P0987 indicates that the powertrain control module (PCM) or transmission control module (TCM) has detected an abnormal voltage or resistance in the transmission fluid pressure (TFP) sensor/switch 'E' circuit. The module sets this code when the signal from the sensor does not match the expected value for the current operating conditions, indicating a potential fault in the sensor or its circuit.
While the vehicle may still be drivable, this code should be addressed promptly. Ignoring it can lead to poor shift quality, transmission slipping, and potential internal transmission damage over time.
Common symptoms
- Illuminated Check Engine Light
- Harsh or erratic transmission shifting
- Transmission slipping between gears
- Vehicle entering 'limp mode' (restricted to a single gear)
- Decreased fuel efficiency
Likely causes
- Low or dirty transmission fluid
- Faulty transmission fluid pressure sensor/switch 'E'
- Damaged, corroded, or loose wiring and connectors in the sensor circuit
- Clogged transmission fluid filter or internal fluid passages
- Mechanical internal transmission failure
- Faulty PCM or TCM (rare)
What to check before replacing parts
Check the transmission fluid level and condition.
Look for: Fluid that is low, burnt, or heavily contaminated with debris indicates a fluid issue that could cause incorrect pressure readings or internal damage.
Visually inspect the wiring harness and connectors for the TFP sensor 'E'.
Look for: Look for frayed wires, melted insulation, corrosion on the pins, or loose connections that could interrupt the circuit.
Test the TFP sensor 'E' circuit for continuity and resistance using a digital multimeter.
Look for: Compare the resistance and voltage readings to the manufacturer's specifications; an open or short circuit indicates a wiring issue.
Test the transmission fluid pressure sensor/switch 'E' directly.
Look for: If the sensor's internal resistance is out of specification or it fails to change state when pressure is applied, the sensor is faulty.
Perform a mechanical transmission fluid pressure test using a manual gauge.
Look for: If the mechanical pressure is normal but the sensor reads otherwise, the sensor or circuit is at fault. If mechanical pressure is low, there is an internal transmission or pump issue.
This page explains the generic P0987 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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