Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the part of the car that checks how much ammonia is in the exhaust is getting too much power. It's like a heater getting too hot because it's plugged into the wrong outlet.
The P24E8 code is triggered when the Engine Control Module (ECM) detects a higher than expected voltage in the NH3 sensor heater circuit.
The NH3 sensor is used in vehicles with selective catalytic reduction (SCR) systems to monitor ammonia levels in the exhaust. The sensor has a heater to ensure it operates correctly in various temperatures. If the ECM detects that the voltage in the heater circuit is higher than expected, it sets the P24E8 code.
• Check Engine Light is on
• Possible decrease in fuel efficiency
• Potential emissions test failure
• Faulty NH3 sensor heater
• Wiring issues such as short to power
• Faulty ECM
NH3: Ammonia, a compound used in SCR systems to reduce emissions.
SCR: Selective Catalytic Reduction, a system used to reduce nitrogen oxide emissions in diesel engines.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connections to the NH3 sensor.
• Test the NH3 sensor heater circuit for proper voltage.
• Replace the NH3 sensor if faulty.
• Repair or replace damaged wiring.
• Replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $500
Moderate
• Volkswagen Passat
• Audi A3
• BMW 3 Series
• Regular maintenance checks of the exhaust system.
• Ensure proper vehicle software updates.
• Avoid using low-quality fuel.
Sensor Issue
• Do not ignore the Check Engine Light.
• Consult a professional mechanic for accurate diagnosis.
• Avoid driving extensively with this code active.
Check with your vehicle manufacturer for possible warranty coverage on emissions-related components.
This code has become more common with the increased use of SCR systems in diesel vehicles to meet emissions standards.
Moderate – It should be addressed soon to avoid potential damage to the emissions system.
Driving with a malfunctioning emissions system can lead to higher emissions and potential legal issues in areas with strict emissions laws.
• Engine at operating temperature
• Vehicle in closed-loop operation
The NH3 sensor is typically located in the exhaust system, downstream of the SCR catalyst.
Q: Can I drive with the P24E8 code?
A: It's not recommended as it may lead to increased emissions and potential damage to the emissions system.
Q: How do I reset the Check Engine Light after fixing the issue?
A: You can use an OBD-II scanner to clear the code, but ensure the issue is resolved first.
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Fitment Required · Vehicle-fitment part
Relevant when catalyst-efficiency or emissions faults persist after proper diagnosis.
Catalyst-efficiency faults sometimes point toward converter problems after proper testing.
Catalytic converters are highly vehicle-specific and should not be purchased by code alone.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.