Fix P20AC: STEP-BY-STEP diagnostic GUIDE!

The P20AC: Reductant Metering Unit Temperature Sensor Circuit fault code refers to a problem in the circuit related to the temperature sensor of the reductant metering unit, which is part of the diesel exhaust fluid (DEF) system. This sensor monitors the temperature to ensure proper DEF dosing and operation. Faults in the circuit can lead to improper DEF dosing, affecting the vehicle’s emissions control. The issue may be caused by a faulty sensor, wiring or connector issues, or circuit problems.

P20AC – Quick Overview

CodeInformation
MeaningP20AC: Reductant Metering Unit Temperature Sensor Circuit
Is it serious?Yes, improper temperature monitoring can lead to incorrect DEF dosing, affecting emissions control and system performance.
Possible causes– Faulty temperature sensor
– Wiring or connector issues
– Sensor circuit problems
How to diagnose?– Test the reductant metering unit temperature sensor
– Measure sensor circuit performance
– Inspect wiring and connectors

P20AC Meaning

The P20AC code indicates a fault in the reductant metering unit temperature sensor circuit, which is essential for monitoring the temperature of the diesel exhaust fluid (DEF). The temperature sensor ensures that the DEF is injected at the proper temperature for optimal emissions control. If this circuit malfunctions, it could result in improper DEF dosing, leading to increased emissions or performance issues.

Step-by-step diagnostic guide

ActionDescriptionTools Needed
Check for Other CodesUse an OBD-II scanner to check for additional related fault codes, which may provide more insight into the reductant metering system issue.OBD-II Scanner
Test the Reductant Metering Unit Temperature SensorUse a multimeter or diagnostic tool to test the temperature sensor and ensure it is providing accurate readings within the manufacturer’s specifications.Multimeter, Diagnostic Tool
Measure Sensor Circuit PerformanceCheck the voltage and resistance of the sensor circuit using a multimeter to ensure proper performance. Compare the values to manufacturer specs.Multimeter
Inspect Wiring and ConnectorsVisually inspect the wiring and connectors associated with the temperature sensor for signs of damage, corrosion, or loose connections.Flashlight, Multimeter
Clear the Code and Test DriveAfter completing repairs, clear the fault code using an OBD-II scanner and take the vehicle for a test drive to confirm the issue is resolved.OBD-II Scanner, Vehicle Owner’s Manual
Recheck for CodesAfter the test drive, re-scan the vehicle to ensure the P20AC code does not return. If it reappears, further diagnostics may be needed.OBD-II Scanner
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