P087C

Code

Generic P — Powertrain

Clutch Position Sensor B Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 24 EN: 46 RU: 27

AI status

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Page language: EN

Causes

Short to ground in the clutch position sensor B signal wire
Open or damaged wiring/connector (intermittent short or high resistance)
Low or missing reference voltage or poor ground at the sensor
Failed clutch position sensor (internal short or open)
Corroded or pushed-out terminal in the connector
Faulty PCM/TCU input circuit (rare)

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Clutch-dependent functions may be disabled (no-crank protection may prevent starting on some vehicles)
Cruise control may be disabled
Gear selection/shift issues or transmission limp mode on some systems
Intermittent or permanent failure to detect clutch pedal position

What to check

Scan for freeze frame and snapshot data; note condition when code set
Check live data for clutch position sensor A and B signals while operating pedal
Visually inspect harness and connector for damage, corrosion, or pushed pins
Back-probe sensor connector and measure signal, reference, and ground voltages with ignition ON (engine OFF)
Perform continuity check from sensor signal pin to PCM input and to chassis ground as appropriate
Wiggle test wiring while observing live data to reproduce the fault

Signal parameters

Reference voltage: typically 5.0 V (verify vehicle-specific spec)
Expected sensor signal: commonly 0.2–4.8 V across pedal travel (varies by design)
Low-fault threshold: signal often flagged as 'low' when below ~0.2–0.5 V (vehicle-specific)
Ground continuity: sensor ground should be near 0 Ω to chassis/ECM ground
Connector resistance: signal wire continuity should be low (single-digit ohms to PCM input)

Diagnostic algorithm

Retrieve live data and freeze frame. Note when the code set and behavior of sensor B vs sensor A.
Visually inspect the sensor, connector, and harness from pedal/actuator to the module for damage, corrosion, or pin backout.
With ignition ON (engine OFF), back-probe the sensor connector: verify reference voltage (≈5 V), sensor signal voltage, and ground. If reference or ground missing, trace back to the ECM power/ground.
If reference and ground are present but signal is low, check continuity of the signal wire to the PCM. Look for short to ground using an ohmmeter (with battery disconnected).
Wiggle the harness and connectors while monitoring live data to find intermittent faults.
If wiring and connectors are good but signal remains low, swap or bench-test the sensor (if serviceable) or replace the sensor B.

Likely causes

Damaged wiring or pin pushed out of connector to sensor
Corroded/loose connector or terminal at the sensor
Sensor failure (internal short to ground)
Loss of reference 5V supply or engine control module ground
Aftermarket work or routing causing chafing/short to chassis ground

Fault status

⚠️ Status

P087C — Clutch Position Sensor B Circuit Low: sensor B signal voltage is below expected threshold (possible short to ground, missing reference/ground, bad connector, or failed sensor).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours