Fix P20AE: STEP-BY-STEP diagnostic GUIDE!

The P20AE: Reductant Metering Unit Temperature Sensor Circuit Low fault code indicates that the circuit for the reductant metering unit temperature sensor is experiencing low voltage. This sensor monitors the temperature of the diesel exhaust fluid (DEF) to ensure proper dosing. Low voltage in the circuit can result in incorrect sensor readings, potentially affecting the DEF injection process. This issue may be caused by a faulty sensor, wiring issues, or a problem within the sensor circuit.

P20AE – Quick Overview

CodeInformation
MeaningP20AE: Reductant Metering Unit Temperature Sensor Circuit Low
Is it serious?Yes, it can affect proper DEF dosing, which may lead to emissions control issues and increased emissions.
Possible causes– Low voltage in the temperature sensor circuit
– Faulty temperature sensor
– Wiring or connector issues
How to diagnose?– Measure voltage in the temperature sensor circuit
– Test the reductant metering unit temperature sensor
– Inspect wiring and connectors

P20AE Meaning

The P20AE code indicates that the voltage in the reductant metering unit temperature sensor circuit is lower than expected. This sensor is responsible for monitoring the temperature of DEF to ensure it is injected at the correct temperature. Low voltage can lead to inaccurate sensor readings, affecting the performance of the DEF injection system and possibly causing higher emissions.

Step-by-step diagnostic guide

ActionDescriptionTools Needed
Check for Other CodesUse an OBD-II scanner to check for additional related fault codes that may help provide more insight into the issue with the sensor or system.OBD-II Scanner
Measure Voltage in the CircuitUse a multimeter to measure the voltage in the temperature sensor circuit and compare it to the manufacturer’s specifications to confirm low voltage.Multimeter
Test the Reductant Metering Unit Temperature SensorUse a diagnostic tool or multimeter to test the sensor’s functionality and ensure it is operating within the correct voltage range.Multimeter, Diagnostic Tool
Inspect Wiring and ConnectorsVisually inspect the wiring and connectors leading to the temperature sensor for signs of damage, corrosion, or disconnections that could cause low voltage.Flashlight, Multimeter
Clear the Code and Test DriveAfter completing repairs, clear the code using an OBD-II scanner and take the vehicle for a test drive to ensure the issue has been resolved.OBD-II Scanner, Vehicle Owner’s Manual
Recheck for CodesRe-scan the system after the test drive to ensure that the P20AE code does not return. If the code reappears, further diagnostics may be required.OBD-II Scanner
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