What it means
The ECM detects a circuit high fault on the clutch position sensor b circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Clutch position sensor B sends a position signal through its circuit to the control module for shift coordination. The module sets P087D when the signal rises above its expected range, which can happen if the signal wire is shorted to battery voltage or the sensor circuit is open.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- Connector pins corroded - high contact resistance
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Save freeze-frame data and watch sensor B live data while moving the clutch, noting whether the reading remains abnormally high or is fixed.
- Inspect the sensor B harness for rubbed or pinched insulation and contact with power wiring that could place battery voltage on the signal circuit.
- Check the connector for backed-out, corroded, or poorly seated terminals and verify sensor power and ground connections against the manufacturer's specification.
- With the circuit isolated according to service information, test the signal wire for a short to battery voltage and check for an open between the sensor and module.
- If the wiring and connections pass, test clutch position sensor B for an internal open and replace it if its output does not meet the manufacturer's specification.
Common fixes
- Reseat the sensor B connector and secure the harness away from power sources.
- Repair an open or short to battery voltage in the sensor B signal wiring.
- Replace damaged or corroded connector terminals.
- Replace clutch position sensor B if its internal circuit is open.
Can I keep driving?
Limit driving and stop in a safe place if the transmission misses shifts, behaves harshly, or enters limp mode. A high or invalid clutch signal can interfere with shift control and leave the vehicle with limited gear operation.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.