Code
P08B6
Generic
P — Powertrain
Clutch Pedal Position Sensor B Circuit Low
Views:
UK: 26
EN: 38
RU: 26
AI status
Completed
Completed
100%
Causes
- Damaged or shorted wiring (signal wire shorted to ground)
- Corroded, loose or damaged connector at sensor or PCM
- Failed/clogged clutch pedal position sensor (sensor B)
- Loss of reference voltage or ground to the sensor
- Poor or intermittent chassis/engine ground
- PCM input circuit fault (rare)
Symptoms
- Malfunction Indicator Lamp (MIL) or DTC lamp illuminated
- Clutch-interlock functions affected (engine may not crank in clutch-required start systems)
- Cruise control or shift interlock may be disabled
- Erratic or no clutch pedal position reading in live data (stuck low)
- Transmission or driveability warnings/limp mode in some vehicles
What to check
- Read stored/active codes and freeze frame with a capable scan tool
- Inspect clutch pedal area wiring and connector for corrosion, damage, pin push-out or contamination
- Visually check harness routing for chafing, kinks, or recent repair splices
- Monitor live data for Clutch Pedal Position Sensor B with key ON, engine OFF
- Check for other related codes (reference/ground/communication faults)
Signal parameters
- Typical reference voltage: ~5.0 V (key ON) to the sensor (varies by manufacturer)
- Expected signal voltage range: approximately 0.5–4.5 V during pedal travel (varies)
- Low/failed condition: signal voltage near 0.0–0.2 V (indicates short to ground or sensor output low)
- Reference ground: continuity to chassis ground should be near 0 Ω; open/poor ground will affect readings
Diagnostic algorithm
- Retrieve all codes and vehicle-specific data; note freeze-frame and MIL status.
- With key ON (engine OFF) backprobe the sensor connector: verify reference voltage (≈5 V) and ground presence. If reference is missing, trace upstream to fuse/ECU.
- Measure signal pin voltage while gently operating the clutch pedal. If signal remains low (
- Wiggle the harness and connector while monitoring live data to look for intermittent changes. Inspect connector pins for corrosion/bent pins.
- If reference and ground are present but signal is low, unplug connector and check for short to ground on the signal wire (measure continuity between signal wire and chassis ground; large continuity indicates short).
- Check continuity between the sensor signal pin and the PCM input pin. Repair any open or shorted wiring found.
- If wiring and connector test good, bench-test or replace the clutch pedal position sensor B per manufacturer procedure. Re-test live data after replacement.
- If replacement does not clear the issue and wiring is confirmed good, test or inspect PCM input circuit and grounds; consult manufacturer service data before replacing PCM.
- Clear codes and perform functional test/road test to verify repair. If code returns, continue with manufacturer-specific advanced diagnostics.
Likely causes
- Connector corrosion or bent pins at clutch pedal sensor
- Broken insulation or pinched harness where it rubs on body/frame
- Sensor internal element failure (signal output stuck low)
- Open reference feed or sensor ground resulting in low output
- Aftermarket modifications or recent repairs disturbed wiring/connector
Fault status
Status
Clutch Pedal Position Sensor B Circuit Low — PCM detected the sensor B signal is below the expected threshold (possible short to ground, loss of reference/ground, or sensor failure). Code stored when condition persists.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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