P08B4 code meaning
Clutch Pedal Position Sensor B Circuit/Open
Powertrain system Generic code P08xx codes Check engine light
What P08B4 means
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.
P08B4 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P08B4
- Warning lamp on
- Start-stop disabled
- Correlation code P08B9 may be stored as well
Common causes of P08B4
- Most 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
- Less likelyFaulty sensor B input in the engine control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Clutch pedal position sensor bWiring harnessECM
What each part of P08B4 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 8 | Area: transmission. |
| B4 | The exact fault in that area. |
What to do next
- Note P08B4 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P08B4
What does P08B4 mean?
P08B4 means "Clutch Pedal Position Sensor B Circuit/Open". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P08B4?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P08B4 fail an emissions test?
Yes, it can. P08B4 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P08B4 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P08B4 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.