What it means
The control module wake-up circuit signal is above the expected range. The code does not establish that a module will remain awake or drain the battery.
At a glance
- Usually lights the check-engine light
How it works
A wake-up circuit signals a control module when it should switch on. The monitoring module checks that the signal does not remain above its expected range. P24F1 sets when the wake-up circuit is too high, which can happen if the wire contacts battery voltage or a connection fault alters the signal.
Common causes
Most likely first.
- Wake-up wire shorted to battery voltage
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light
- Intermittent electrical functions
- A control module may remain powered when it should be off
How to diagnose it
- Scan for related wake-up, communication, and battery-drain codes, and identify whether a module stays powered or functions intermittently.
- Inspect the wake-up wire routing for pinching or contact with a battery-positive feed, and check connectors for corrosion or damage.
- With the vehicle in the specified key-off state, check whether the affected module remains powered when it should shut down.
- Use the wiring diagram to measure the wake-up signal at the module in the relevant key states and compare readings with the manufacturer's specification.
- Isolate harness sections and check for a short to battery voltage, paying particular attention to areas where the wake-up wire runs alongside B+ wiring.
- If the wiring and connectors pass, test the module input and shutdown behavior using the manufacturer's procedure.
Common fixes
- Repair a pinched wake-up wire contacting a battery-positive supply.
- Clean or replace corroded or damaged connector terminals.
- Correct harness routing or insulation damage that lets the wake-up circuit contact a B+ source.
- Repair or replace the module only if manufacturer testing confirms its wake-up input or shutdown control is faulty.
Can I keep driving?
If a module remains powered after shutdown, the battery may discharge and leave the vehicle unable to start. Limit use until the cause is found, especially if the vehicle has shown a weak battery or unreliable electrical functions.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.