P24EE code meaning
NH3 Sensor Processor Performance
Powertrain system Generic code P24xx codes Check engine light
What P24EE means
P24EE says the microcontroller inside the NH3 sensor module has failed its own self-test, for example a watchdog reset, a RAM or ROM error or a timing fault. The engine controller only learns this through the status the sensor sends, because the processor is what runs the probe, the heater and the J1939 messages. Navistar explains for the 2013 N13 that its mid-bed ammonia sensor diagnoses itself and that probe and module are separate parts, ordered individually; a processor fault therefore normally means replacing the module. Repeated resets can also come from an unstable supply, so check that first. No manufacturer documents P24EE publicly. CARB requires fault detection on heavy-duty sensors. P24ED is the memory fault.
P24EE at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P24EE
- Check engine light on
- NH3 sensor data missing or frozen
Common causes of P24EE
- Most likelyElectronics of the NH3 sensor module failed
- PossibleUnstable supply voltage causing processor resets
- Less likelyModule damaged by heat or water ingress
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Nh3 sensorSensor microcontroller
What each part of P24EE 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). |
| EE | The exact fault in that area. |
What to do next
- Note P24EE 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 P24EE
What does P24EE mean?
P24EE means "NH3 Sensor Processor Performance". P24EE says the microcontroller inside the NH3 sensor module has failed its own self-test, for example a watchdog reset, a RAM or ROM error or a timing fault. It is a generic code, so it means the same on every make.
Is it safe to drive with P24EE?
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 P24EE fail an emissions test?
Yes, it can. P24EE 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 P24EE to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. This is a job for a workshop.
Will P24EE clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.