P08AC code meaning
Clutch Pedal Position Not Learned
Powertrain system Generic code P08xx codes Check engine light
What P08AC means
The engine controller has to know at which pedal position the clutch is fully released or disengaged. GM teaches the fully applied position at the factory and then adapts it over time to clutch wear. P08AC is set when this learned value falls outside a window (LV7 1.4 L: 7–33 %, 2019 Corvette ZR1: 9–36 % of travel) or when the manufacturer's enable counter shows the learn was never completed; 250 ms loop, Type A, MIL after one trip. Before 2018 GM used P080A. After replacing the sensor, pedal parts, clutch or ECM, a relearn with a scan tool is needed; FCA, for example, issued a Renegade bulletin calling for a clutch pedal sensor learn. Circuit faults (P08A9/P08AA) must be cleared first.
P08AC at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.3 to 1 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P08AC
- Malfunction indicator lamp on
- Start-stop, cruise control or automatic parking brake release not working as expected
Common causes of P08AC
- Most likelyRelearn not performed after replacing the sensor, clutch parts or engine control module
- PossibleLearned position drifted out of the allowed window (worn clutch, wrong pedal stop, air in hydraulics)
- PossibleLearn procedure aborted, for example by low battery voltage
- Less likelyFaulty or misaligned clutch pedal sensor preventing a valid learn
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 aWiring harnessECM
What each part of P08AC 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. |
| AC | The exact fault in that area. |
What to do next
- Note P08AC 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 P08AC
What does P08AC mean?
P08AC means "Clutch Pedal Position Not Learned". The engine controller has to know at which pedal position the clutch is fully released or disengaged. It is a generic code, so it means the same on every make.
Is it safe to drive with P08AC?
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 P08AC fail an emissions test?
Yes, it can. P08AC 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 P08AC to fix?
Difficulty: medium. A typical repair takes 0.3 to 1 hours of work. This is a job for a workshop.
Will P08AC clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.