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
| Code | Information |
|---|---|
| Meaning | P20AC: 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
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use 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 Sensor | Use 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 Performance | Check 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 Connectors | Visually 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 Drive | After 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 Codes | After 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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