The P20A3: Reductant Purge Control Valve Circuit High fault code indicates that the circuit controlling the reductant purge valve is experiencing higher-than-expected voltage. The reductant purge valve is responsible for managing the flow of diesel exhaust fluid (DEF) within the emissions system, and high voltage in the circuit can prevent the valve from functioning correctly. This issue may result from wiring problems, a faulty valve, or a malfunctioning control module.
P20A3 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P20A3: Reductant Purge Control Valve Circuit High |
| Is it serious? | Yes, it can affect the emissions system’s functionality, potentially leading to increased emissions and triggering warning lights. |
| Possible causes | – High voltage in the reductant purge control valve circuit – Faulty reductant purge control valve – Faulty control module |
| How to diagnose? | – Measure voltage in the control valve circuit – Test the reductant purge control valve – Check the control module functionality |
P20A3 Meaning
The P20A3 code signals that the circuit controlling the reductant purge control valve is receiving a higher voltage than specified. This valve controls the flow of DEF within the exhaust system to reduce emissions. High voltage can cause improper valve operation, leading to inefficient DEF dosing and increased emissions. The fault may be caused by a wiring issue, a malfunctioning valve, or a faulty control module.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for additional codes related to the emissions or reductant system for more context on the problem. | OBD-II Scanner |
| Measure Voltage in the Circuit | Use a multimeter to measure the voltage in the reductant purge control valve circuit and compare it to the manufacturer’s specifications to confirm high voltage. | Multimeter |
| Test the Reductant Purge Control Valve | Use a diagnostic tool to test the operation of the reductant purge control valve and verify that it is functioning within the specified voltage range. Replace if necessary. | Multimeter, Diagnostic Tool |
| Check the Control Module Functionality | Inspect the control module that manages the reductant purge valve for signs of malfunction or incorrect signal output to the valve. | Diagnostic Tool |
| 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 verify that 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 P20A3 code does not return. If the code reappears, further diagnostics may be needed. | OBD-II Scanner |
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