Faulty clutch position sensor B, which may have an internal short or open circuit; Damaged or corroded wiring harness or connector at the sensor or TCM; Poor electrical connection due to loose pins or water intrusion; Failed TCM or a software glitch in the transmission control module; Mechanical issues with the clutch assembly, such as a worn release bearing or fork, causing the sensor to read out of range; Contamination or debris on the sensor tip or reluctor wheel

DTC codes / P08xx · Transmission / P087A

P087AClutch Position Sensor B Circuit

Q: What does code P087A mean?

Clutch Position Sensor B Circuit. P087A is a generic powertrain code that indicates the transmission control module (TCM) has detected an implausible or out-of-range signal from the clutch position sensor B circuit. This sensor is typically used on vehicles with an automated manual transmission or dual-clutch transmission to monitor clutch engagement, and the TCM sets the code when the voltage or signal does not match expected values for the current driving conditions.

P087A is a generic powertrain code that indicates the transmission control module (TCM) has detected an implausible or out-of-range signal from the clutch position sensor B circuit. This sensor is typically used on vehicles with an automated manual transmission or dual-clutch transmission to monitor clutch engagement, and the TCM sets the code when the voltage or signal does not match expected values for the current driving conditions.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaTransmission

Symptoms you may notice

Illumination of the check engine light or transmission warning light, often with no other noticeable symptoms
Harsh or delayed gear shifts, especially when engaging or disengaging the clutch
The transmission may fail to engage a gear or may slip out of gear unexpectedly
A noticeable loss of power or hesitation during acceleration
In some cases, the vehicle may enter limp mode and restrict shifting to a single gear

Common causes, most likely first

Faulty clutch position sensor B, which may have an internal short or open circuit
Damaged or corroded wiring harness or connector at the sensor or TCM
Poor electrical connection due to loose pins or water intrusion
Failed TCM or a software glitch in the transmission control module
Mechanical issues with the clutch assembly, such as a worn release bearing or fork, causing the sensor to read out of range
Contamination or debris on the sensor tip or reluctor wheel

How to diagnose and fix it

Use an OBD-II scanner to retrieve the code and check for any related transmission codes; clear the code and test-drive to see if it returns
Visually inspect the clutch position sensor B and its wiring for obvious damage, corrosion, or loose connections
Perform a voltage drop test on the sensor circuit to check for excessive resistance in the wiring
Check the sensor's resistance or voltage output with a multimeter and compare to manufacturer specifications
If the sensor is faulty, replace it and clear the codes; follow the manufacturer's procedure for calibration or relearn if required
If the sensor and wiring are good, inspect the clutch mechanism for wear or misalignment that could affect sensor readings
As a last resort, diagnose the TCM for internal faults or update its software if a known issue exists

Clutch Sensor B Circuit Pitfalls

A common mistake is replacing the clutch position sensor without checking the wiring harness, as chafed wires near the transmission bell housing often cause intermittent signals.
The code can be set by a mechanical problem such as a worn clutch fork that prevents the sensor from reaching its full range of motion, so always inspect the clutch assembly before condemning the sensor.
On some vehicles, a low or weak battery can cause voltage spikes that trigger this code, so verify battery health and charging system operation first.
After replacing the sensor, many transmissions require a relearn procedure using a scan tool; skipping this step can cause the code to return immediately.
This code is often stored alongside other transmission codes like P087B or P087C, which indicate related circuit issues, so diagnosing all codes together is essential.

Can I keep driving with P087A?

You can usually drive the vehicle with this code, but avoid aggressive acceleration or heavy loads because the transmission may not shift properly and could enter limp mode. If the vehicle feels sluggish or refuses to shift, seek service soon to prevent further transmission damage.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.