P20AF Code - Reductant Metering Unit Temperature Sensor Circuit High
Quick Answer
The P20AF diagnostic trouble code (DTC) refers to the Reductant Metering Unit Temperature Sensor Circuit High. Common causes include Faulty Temperature Sensor: A malfunctioning temperature sensor in the reductant metering unit can trigger the P20AF code, Wiring Issues: Corrosion, damage, or poor connections in the wiring harness connected to the temperature sensor can cause high voltage signals, Software Glitch: An issue with the ECM software or calibration can lead to erroneous readings from the temperature sensor. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P20AF indicates Reductant Metering Unit Temperature Sensor Circuit High.
- Common causes
- Common causes include Faulty Temperature Sensor: A malfunctioning temperature sensor in the reductant metering unit can trigger the P20AF code, Wiring Issues: Corrosion, damage, or poor connections in the wiring harness connected to the temperature sensor can cause high voltage signals, Software Glitch: An issue with the ECM software or calibration can lead to erroneous readings from the temperature sensor.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P20AF Description
The P20AF diagnostic trouble code (DTC) refers to the Reductant Metering Unit Temperature Sensor Circuit High. This code is typically found in diesel vehicles equipped with a selective catalytic reduction (SCR) system. The reductant metering unit is responsible for injecting diesel exhaust fluid (DEF) into the exhaust stream to reduce harmful emissions. The temperature sensor in the unit monitors the temperature of the DEF to ensure it is at the optimal temperature for the SCR system to function effectively.
Common Causes of P20AF
- Faulty Temperature Sensor: A malfunctioning temperature sensor in the reductant metering unit can trigger the P20AF code.
- Wiring Issues: Corrosion, damage, or poor connections in the wiring harness connected to the temperature sensor can cause high voltage signals.
- Software Glitch: An issue with the ECM software or calibration can lead to erroneous readings from the temperature sensor.
- DEF Contamination: Contaminated DEF can affect the temperature sensor's readings and trigger the P20AF code.
- Environmental Factors: Extreme temperatures or exposure to moisture can also impact the accuracy of the temperature sensor readings.
Symptoms of P20AF
- Check Engine Light: The most common symptom associated with the P20AF code is the illumination of the check engine light on the vehicle's dashboard.
- Reduced Engine Performance: The vehicle may experience a decrease in engine performance, including reduced power and acceleration.
- Increased Emissions: The vehicle may produce higher emissions than normal due to incorrect DEF dosing.
- Poor Fuel Efficiency: Incorrect DEF dosing can lead to poor fuel efficiency, resulting in increased fuel consumption.
How to Fix P20AF
- Diagnose the Issue: Use a diagnostic scan tool to retrieve the DTC and pinpoint the exact cause of the high voltage signal from the temperature sensor.
- Inspect Wiring and Connections: Check the wiring harness for any signs of damage, corrosion, or loose connections. Repair or replace as needed.
- Test Temperature Sensor: Test the temperature sensor to ensure it is functioning correctly. Replace the sensor if it is found to be faulty.
- Clear DTC and Reset ECM: Clear the DTC from the ECM memory using the scan tool and reset the ECM to see if the issue persists.
- Verify Repair: After completing the repair process, test drive the vehicle to ensure that the check engine light does not reappear and that the SCR system is functioning properly.
Cost to Fix P20AF
The typical repair costs for addressing the P20AF code can vary depending on the specific cause of the issue and the vehicle's make and model. In general, replacing a faulty temperature sensor or repairing wiring issues can range from $150 to $400, including parts and labor. However, additional costs may apply if other components need to be replaced or if further diagnostics are required. It's recommended to consult with a qualified mechanic or auto repair shop to obtain a more accurate estimate based on the individual circumstances. Keep in mind that labor rates can vary between different repair facilities, so it's advisable to inquire about rates in your local area.
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