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 a sensor that checks the temperature of a special liquid used to clean the car's exhaust. It's like when a thermometer isn't working right.
The P20AD code indicates an issue with the temperature sensor in the reductant metering unit, which is responsible for monitoring the temperature of the diesel exhaust fluid (DEF) used in the Selective Catalytic Reduction (SCR) system.
The reductant metering unit temperature sensor monitors the temperature of the DEF to ensure optimal performance of the SCR system. If the sensor's readings are out of the expected range, the engine control module (ECM) will trigger the P20AD code, indicating a potential issue with the sensor or its circuit.
• Check Engine Light illuminated
• Possible reduction in fuel efficiency
• Potential increase in emissions
• Faulty reductant metering unit temperature sensor
• Wiring issues such as shorts or open circuits
• Corroded or damaged connectors
SCR: Selective Catalytic Reduction, a system used to reduce emissions in diesel engines.
DEF: Diesel Exhaust Fluid, a liquid used in the SCR system to reduce emissions.
• Use an OBD-II scanner to confirm the P20AD code.
• Visually inspect the wiring and connectors for damage.
• Test the temperature sensor with a multimeter to ensure proper resistance.
• Replace the faulty temperature sensor.
• Repair or replace damaged wiring or connectors.
• Clear the code and test drive the vehicle to ensure the issue is resolved.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 2500
• Regularly inspect wiring and connectors for damage.
• Ensure the DEF tank is filled with high-quality fluid.
• Perform routine maintenance as per the vehicle's service schedule.
Sensor Issue
• Do not ignore the Check Engine Light; address the issue promptly.
• Consult a professional mechanic if unsure about the repair process.
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
The P20AD code has become more common with the increased use of SCR systems in diesel vehicles to meet emissions standards.
Moderate – Addressing this issue promptly can prevent further emissions problems and maintain vehicle performance.
Operating a vehicle with a malfunctioning emissions system may violate local emissions laws.
• Engine at operating temperature
• Vehicle in a safe, stationary position
The reductant metering unit temperature sensor is typically located near the DEF tank or along the SCR system's fluid lines.
Q: Can I drive with a P20AD code?
A: While the vehicle may still be drivable, it's best to address the issue promptly to avoid increased emissions and potential damage to the SCR 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, or the light may turn off automatically after several drive cycles if the issue is resolved.
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