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 in your car that checks the temperature of a part that helps reduce pollution.
The P20AC code is triggered when the Engine Control Module (ECM) detects a problem with the temperature sensor circuit in the reductant metering unit, which is part of the vehicle's emission control system.
The reductant metering unit temperature sensor is responsible for monitoring the temperature of the Diesel Exhaust Fluid (DEF) system. If the sensor circuit is malfunctioning, it can cause incorrect DEF dosing, leading to increased emissions.
• Check Engine Light is on
• Reduced engine performance
• Increased emissions
• Faulty temperature sensor
• Wiring issues or poor connections
• Faulty ECM
ECM: Engine Control Module
DEF: Diesel Exhaust Fluid
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connections to the temperature sensor.
• Test the temperature sensor for proper operation.
• Replace the faulty temperature sensor.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 2500
• Regular maintenance checks
• Ensure proper DEF levels
• Inspect wiring for damage
Sensor Issue
• Have your vehicle inspected by a professional.
• Avoid ignoring the Check Engine Light.
• Maintain regular service intervals.
Check with your vehicle manufacturer regarding emissions-related warranty coverage.
This code has become more common with the increased use of DEF systems in diesel vehicles to meet emission standards.
Moderate – It's important to address this issue to avoid increased emissions and potential engine performance issues.
Ignoring emission-related issues can lead to failing emissions tests and potential fines.
• Engine at operating temperature
• Vehicle in park or neutral
The temperature sensor is located near the reductant metering unit, typically in the exhaust system.
Q: Can I drive with a P20AC code?
A: It's not recommended to drive for extended periods with this code, as it can lead to increased emissions and potential engine performance issues.
Q: How can I reset the Check Engine Light?
A: After repairs, use an OBD-II scanner to clear the code. If the issue is fixed, the light should stay off.
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