P24F1 code meaning
Control Module Wake-up Circuit High
Powertrain system Generic code P24xx codes Check engine light
What P24F1 means
With P24F1 the wake-up line carries voltage while its driving module has the output switched off, so a short to a battery feed or a second source keeps it live. GM's HPC2 module in the 2016 and 2019 hybrid tables flags 13.21 V or more in the off state, using the same 480-of-560 sample count at 12.5 ms and Type A, MIL after one trip. Mercedes-Benz documents P24F100 in the 8-speed dual-clutch gearbox controller of CLA, GLA and GLB (XENTRY tip LI27.19-P-080869, 2026): the wake line appears shorted to positive, the car may briefly refuse to start, and the cause is signal timing with the ignition switch module, fixed by new SCN coding of that unit. P24EF is open, P24F0 low.
P24F1 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P24F1
- Check engine light and several warning messages
- Temporary no-start condition
- Possible battery drain while parked
Common causes of P24F1
- Most likelyWake-up line shorted to a battery feed
- PossibleSignal timing between ignition module and receiving unit, solved by coding
- Less likelyVoltage fed back from another module that stays awake
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Wake up circuitControl module
What each part of P24F1 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| F1 | The exact fault in that area. |
What to do next
- Note P24F1 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 P24F1
What does P24F1 mean?
P24F1 means "Control Module Wake-up Circuit High". With P24F1 the wake-up line carries voltage while its driving module has the output switched off, so a short to a battery feed or a second source keeps it live. It is a generic code, so it means the same on every make.
Is it safe to drive with P24F1?
Drive gently and only to a workshop. With P24F1 the car can go into limp mode (reduced power) to protect itself.
Will P24F1 fail an emissions test?
Yes, it can. P24F1 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 P24F1 to fix?
Difficulty: hard. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P24F1 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.