What it means
A general electrical fault is detected in the NH3 sensor circuit. The code alone does not specify the failed component or the sensor’s location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
An NH3 sensor measures ammonia in the exhaust aftertreatment system so the control module can assess emissions control. P24E1 sets when the module detects an electrical fault somewhere in the NH3 sensor circuit; this general circuit code does not specify a particular sensor location or whether the fault is in the sensor, wiring, or control circuit.
Common causes
Most likely first.
- Open or short in sensor wiring
- Loose or corroded connector
- NH3 sensor internal fault
- Fault in the sensor control circuit
Symptoms
- Check-engine light on
- Aftertreatment or emissions warning
- Reduced engine power
- Emissions inspection failure
How to diagnose it
- Record freeze-frame data and check for related aftertreatment codes to understand when the NH3 circuit fault was detected.
- Inspect accessible NH3 sensor connectors and wiring for loose connections, corrosion, heat damage, or chafing.
- Use the vehicle wiring diagram to identify the applicable NH3 sensor circuit and check its power, ground, and signal paths as specified by the manufacturer.
- Test circuit continuity and check for opens or shorts in the identified wiring before condemning the sensor.
- If wiring and connections are sound, test the NH3 sensor and control circuit against the manufacturer's specification.
Common fixes
- Reconnect a loose NH3 sensor connector.
- Clean corrosion or repair damaged connector terminals in the NH3 circuit.
- Repair an open or shorted section of sensor wiring.
- Replace the NH3 sensor if it fails the specified test.
Can I keep driving?
If the engine runs normally, cautious driving to arrange diagnosis is generally reasonable, but aftertreatment performance and emissions compliance may be affected. Reduce driving and seek prompt service if power drops or an emissions warning escalates.
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.