P087A
Clutch Position Sensor B Circuit.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 8
- AreaTransmission
- 7A
- FaultThe specific fault in that area
What it means
P087A is the generic code for a fault in the Clutch Position Sensor 'B' circuit. The control unit (engine or transmission, depending on the vehicle) has seen a signal from this sensor that is missing, out of range, stuck or implausible compared with what it expects. Which clutch or sensor is 'B', and which module sets the code, depends on the model and transmission type, such as a manual with a clutch sensor, an automated manual or a dual-clutch.
Symptoms
- Warning light on, such as the engine light or a transmission warning
- Hesitant, jerky or harsh gear changes on automated or dual-clutch gearboxes
- Engine will not start, or start-stop and cruise control are disabled on cars that rely on the clutch signal
- Transmission stuck in one gear or in a limp mode
- Difficulty selecting gears or a slipping or dragging clutch feel
Possible causes
- Damaged, chafed or corroded wiring to the clutch position sensor (open circuit, short to earth or short to voltage)likely
- Poor connection at the sensor or control unit plug (loose pin, water ingress, corrosion)likely
- Faulty clutch position sensor Blikely
- Sensor or its target out of position, loose mounting or contaminated with debris or fluidpossible
- Mechanical clutch actuator or linkage fault causing an implausible position readingpossible
- Low or unstable supply voltage or a poor earth affecting the sensor referencepossible
- Fault inside the control unit, or a software issue where the manufacturer has a known fixrare
How to diagnose
- Read all stored and pending codes and the freeze frame data, and note whether other transmission, clutch or voltage codes are present
- Check for any manufacturer service information or bulletins for your model and transmission type, and confirm which sensor is 'B'
- Visually inspect the sensor, its wiring and the connectors for chafing, heat damage, fluid contamination, corrosion and bent or pushed-back pins
- Check the battery condition and charging voltage, and the relevant earth connections
- Watch live data for the clutch position while operating the clutch or letting the system operate, looking for dropouts, flat lines or jumps
- Using the wiring diagram, test the sensor supply, earth and signal wires for continuity, shorts and correct voltage at the sensor connector
- Check the sensor mounting, air gap or target, and the condition and movement of the clutch linkage or actuator
- Clear the code and road test to confirm whether it returns, and check it is not an intermittent fault
How to fix
- Repair or replace damaged wiring and secure it away from heat and moving parts
- Clean, repair or replace corroded or loose connectors and terminals
- Replace the clutch position sensor if its readings are faulty, then perform any adaptation or calibration the manufacturer requires
- Refit, adjust or clean the sensor and target, and repair or replace worn or faulty clutch actuator or linkage parts
- Correct battery, charging or earth faults found during testing
- Where a known fault is confirmed, update the control unit software to the latest approved calibration
Can I keep driving?
The car may be driveable but could go into limp mode, shift poorly or fail to start, so get it checked soon. Avoid long journeys if the gears are changing harshly or the clutch feels unreliable.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.