Powertrain, generic (extended)

P24F1 Control Module Wake-up Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

Wake-up line shorted to a battery feed
Signal timing between ignition module and receiving unit, solved by coding
Voltage fed back from another module that stays awake

Symptoms

  • Check engine light and several warning messages
  • Temporary no-start condition
  • Possible battery drain while parked

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–900
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

wake up circuitcontrol module

Related codes

P24EFP24F0

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.