Fix P20B0: STEP-BY-STEP diagnostic GUIDE!

The P20B0: Reductant Metering Unit Temperature Sensor Circuit Intermittent/Erratic fault code indicates that the reductant metering unit temperature sensor is sending intermittent or erratic signals. This sensor monitors the temperature of the diesel exhaust fluid (DEF) to ensure proper dosing into the exhaust system. Erratic signals can lead to inaccurate DEF dosing and may affect emissions control. The issue may be caused by intermittent sensor performance, faulty wiring, or connector issues.

P20B0 – Quick Overview

CodeInformation
MeaningP20B0: Reductant Metering Unit Temperature Sensor Circuit Intermittent/Erratic
Is it serious?Yes, it can result in improper DEF dosing, affecting the emissions control system and potentially increasing emissions.
Possible causes– Intermittent sensor issues
– Faulty temperature sensor
– Wiring or connector issues
How to diagnose?– Test the sensor for intermittent issues
– Check the temperature sensor
– Inspect wiring and connectors

P20B0 Meaning

The P20B0 code indicates that the reductant metering unit temperature sensor circuit is producing intermittent or erratic signals. This sensor is responsible for monitoring the temperature of DEF to ensure it is injected at the proper temperature. Erratic signals from the sensor can cause incorrect DEF dosing, leading to poor emissions control and potentially 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 provide further context on the issue with the DEF system.OBD-II Scanner
Test the Sensor for Intermittent IssuesUse a diagnostic tool to monitor the temperature sensor in real-time and observe for any erratic or intermittent signals.Multimeter, Diagnostic Tool
Check the Temperature SensorUse a multimeter to test the sensor’s resistance and voltage to ensure it is operating correctly and compare the readings to manufacturer specifications.Multimeter
Inspect Wiring and ConnectorsVisually inspect the wiring and connectors for signs of damage, corrosion, or loose connections that could cause intermittent signal transmission.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 CodesRe-scan the system after the test drive to ensure that the P20B0 code does not return. If the code reappears, further diagnostics may be required.OBD-II Scanner
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