Fix P206D: STEP-BY-STEP diagnostic GUIDE!

The P206D: Reductant Quality Sensor Circuit High refers to a fault where the reductant quality sensor circuit is experiencing higher-than-expected voltage. This sensor is responsible for monitoring the quality of diesel exhaust fluid (DEF) in the emissions system. High voltage in the circuit can lead to inaccurate readings and affect the performance of the emissions control system. This issue may be caused by a faulty sensor, wiring problems, or connector issues.

P206D – Quick Overview

Code	Information
Meaning	P206D: Reductant Quality Sensor Circuit High
Is it serious?	Yes, high voltage in the sensor circuit can cause inaccurate DEF quality readings, affecting emissions control.
Possible causes	– High voltage in the sensor circuit – Faulty sensor – Wiring or connector issues
How to diagnose?	– Measure voltage in the sensor circuit – Test the sensor – Inspect wiring and connectors

P206D Meaning

The P206D code indicates that the reductant quality sensor circuit is receiving a higher voltage than the manufacturer’s specifications. This sensor monitors the quality of DEF used in the vehicle’s emissions control system. High voltage may cause inaccurate DEF quality readings, leading to improper emissions system operation and increased emissions. The issue could be caused by a malfunctioning sensor, problems with the wiring, or faulty connectors.

Step-by-step diagnostic guide

Action	Description	Tools Needed
Check for Other Codes	Use an OBD-II scanner to check for any additional fault codes related to the reductant system that may provide more information.	OBD-II Scanner
Measure Voltage in the Circuit	Use a multimeter to measure the voltage in the reductant quality sensor circuit and compare it to manufacturer specifications to confirm high voltage.	Multimeter
Test the Sensor	Use a diagnostic tool to test the sensor and verify that it’s operating within the correct voltage range and providing accurate readings.	Multimeter, Diagnostic Tool
Inspect Wiring and Connectors	Inspect the wiring and connectors leading to the sensor for signs of damage, corrosion, or loose connections that may cause high voltage.	Flashlight, Multimeter
Clear the Code and Test Drive	After completing repairs, clear the code with 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	Re-scan the vehicle after the test drive to ensure that the P206D code does not return. If the code reappears, further diagnostics may be required.	OBD-II Scanner