P08B4Clutch Pedal Position Sensor B Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Some manual cars read the clutch pedal with two independent sensors so a single failure can be detected; Ford's 2020–23 gasoline OBD summary describes such a dual PWM layout. Sensor B is the second channel. P08B4 is the general circuit or open-wire fault of that second sensor. No manufacturer documents this code publicly: Ford uses only P08B6/P08B7 for sensor B plus P08B9 for the A/B comparison, and GM's tables cover sensor A alone. The code therefore rests on CARB's requirement to monitor such inputs for circuit faults. Sensor A's counterpart is P08A7. As long as sensor A is healthy the controller can usually still judge the pedal, but start-stop is often locked out until the fault is fixed.
- What you may notice
- Warning lamp on
- Start-stop disabled
- Correlation code P08B9 may be stored as well
- Likely causes
- LikelyLoose connector or broken wire on the sensor B channel
- PossibleInternal fault in clutch pedal position sensor B (often a shared housing with sensor A)
- PossibleMissing supply or ground for sensor B
- RareFaulty sensor B input in the engine control module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €50 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.