Low, degraded or contaminated transmission fluid, or a blocked filter, affecting pressure and the sensor reading; Damaged, chafed or corroded wiring to the pressure sensor or switch (open circuit, short or high resistance); Poor connection at the sensor, internal gearbox connector or control unit plug (corrosion, fluid ingress, bent pins); Faulty pressure sensor or switch; Valve body or solenoid fault causing a real pressure problem that the sensor correctly reports; Fault in the transmission control unit; Low or unstable supply voltage or poor earth to the control unit or sensor.

P0987

Transmission Fluid Pressure Sensor/Switch E Circuit.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
9: AreaTransmission
87: FaultThe specific fault in that area

What it means

P0987 is a generic code for a fault in the Transmission Fluid Pressure Sensor/Switch 'E' circuit. The transmission control unit monitors the signal from this sensor or switch, which reports hydraulic pressure in one circuit of the gearbox. It set the code because the signal was not what it expected, for example an electrical fault in the circuit or a reading that did not match commanded pressure. Which part of the gearbox 'E' refers to depends on the vehicle, so check the manufacturer data for your model.

Symptoms

Gearbox warning light or malfunction light on
Harsh, delayed or flared gear changes
Gearbox stuck in a single gear (limp mode)
Slipping or loss of drive under load
Erratic or no gear position selection or torque converter lock-up
Reduced fuel economy

Possible causes

Low, degraded or contaminated transmission fluid, or a blocked filter, affecting pressure and the sensor readinglikely
Damaged, chafed or corroded wiring to the pressure sensor or switch (open circuit, short or high resistance)likely
Poor connection at the sensor, internal gearbox connector or control unit plug (corrosion, fluid ingress, bent pins)likely
Faulty pressure sensor or switchpossible
Valve body or solenoid fault causing a real pressure problem that the sensor correctly reportspossible
Fault in the transmission control unitrare
Low or unstable supply voltage or poor earth to the control unit or sensorrare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting gearbox temperature, speed and gear when the code set, and look for other gearbox or battery voltage codes.
Check the transmission fluid level, condition and smell using the correct procedure for the model, as some gearboxes need a set temperature or have no dipstick.
Inspect the wiring and connectors between the sensor, the gearbox connector and the control unit for chafing, corrosion, fluid contamination and pin damage.
Check battery condition and charging voltage, and the relevant earths and supply fuses.
Using the manufacturer data, test the sensor circuit for supply, earth and signal voltage, and check wiring continuity and for shorts.
View live data for the pressure sensor or switch status and compare it with expected values at idle and during gear selection.
Where the sensor is accessible, compare its reading or resistance with specification, and check whether it changes with commanded pressure.
If the circuit and sensor are good, carry out a hydraulic pressure test and valve body inspection as the manufacturer specifies.

How to fix

Correct the fluid level or change the fluid and filter using the specified type if it is low, burnt or contaminated.
Repair or replace damaged wiring and clean or replace corroded or damaged connectors.
Replace the pressure sensor or switch if it fails testing, with the correct part for the gearbox.
Repair or replace the valve body, solenoids or other hydraulic components if a genuine pressure fault is confirmed.
Repair charging system or earth faults that cause unstable voltage.
Replace or reprogram the control unit only after confirming it is at fault, or if an updated calibration is a known fix for the model.

Can I keep driving?

Medium severity

It may be driven a short distance if the gearbox shifts normally, but get it checked soon. If it slips, is stuck in limp mode or shifts harshly, limit driving, as continued use can damage the gearbox.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.