Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the sensor that checks if the heater for a special fluid in your car is working right. It's like a thermometer that tells if the heater is on, and it's not working properly.
The P24D3 code is set when the engine control module (ECM) detects a malfunction in the sensor circuit for the reductant heater B. This heater is part of the system that reduces emissions from diesel engines.
The reductant heater B is part of the diesel exhaust fluid (DEF) system, which helps reduce harmful emissions. The sensor monitors the heater's operation to ensure it is functioning correctly. If the ECM detects an issue with the sensor circuit, it triggers the P24D3 code.
• Check Engine Light illuminated
• Possible decrease in fuel efficiency
• Potential increase in emissions
• Faulty reductant heater B sensor
• Damaged wiring or connectors in the sensor circuit
• Faulty ECM
ECM: Engine Control Module
DEF: Diesel Exhaust Fluid
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage.
• Test the reductant heater B sensor for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the reductant heater B sensor if faulty.
• Update or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $500
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Ram 2500
• Regular maintenance of the DEF system
• Inspect wiring and connectors periodically
• Use high-quality diesel exhaust fluid
Sensor Issue
• Do not ignore the Check Engine Light.
• Have your vehicle inspected by a professional.
• Avoid driving long distances until the issue is resolved.
Check with your vehicle manufacturer for warranty coverage on emissions-related components.
This code has been more prevalent in diesel vehicles as emission standards have become stricter.
Moderate – It affects emissions and may impact vehicle performance over time.
Driving with a malfunctioning emission system can lead to increased pollution and may not comply with local emission laws.
• Engine at operating temperature
• DEF system operational
The reductant heater B sensor is typically located near the DEF tank or in the DEF supply line.
Q: Can I drive with a P24D3 code?
A: It's not recommended to drive for extended periods with this code, as it can affect emissions and potentially lead to further issues.
Q: How can I reset the P24D3 code?
A: The code can be reset using an OBD-II scanner, but it's important to fix the underlying issue first.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.