What it means
An open or other fault is detected in the NH3 sensor heater circuit. The code does not specify the circuit layout or the resulting control strategy.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The NH3 sensor has a heater that brings its sensing element to operating temperature so it can measure ammonia in the exhaust. P24E6 indicates the control module detects an open or other fault in the heater circuit; the code alone does not identify whether the sensor, wiring, or heater driver has failed.
Common causes
Most likely first.
- Burnt-out heater winding inside the sensor
- Broken wire or unplugged connector
- Failed heater driver stage in the dosing module
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 scan-tool status for the NH3 heater circuit and related aftertreatment faults.
- Inspect the sensor connector and heater harness for disconnection, broken wires, heat damage, or corrosion.
- Use the wiring diagram to identify the heater circuit, then check for an open in its wiring and connector terminals.
- Test the heater element and its power and control paths using the manufacturer's procedure.
- If the sensor and wiring pass, check the heater driver in the dosing or control module according to manufacturer guidance.
Common fixes
- Reconnect and secure a loose sensor connector.
- Repair a broken heater-circuit wire or damaged connector.
- Replace the NH3 sensor if its heater winding is open or otherwise fails specification.
- Repair or replace the heater driver module only after circuit and sensor tests identify it as faulty.
Can I keep driving?
The vehicle may remain drivable, but the NH3 sensor may not warm up correctly, affecting emissions monitoring and potentially causing reduced power or an aftertreatment warning. Avoid extended use if warnings or power limits appear, and have the heater circuit diagnosed.
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.