How severe is this DTC?
The severity of this code is normally moderate, but P20A0 can be serious if harmful gases are released from the exhaust, which becomes a safety issue requiring immediate attention.
What are some of the symptoms of the code?
Symptoms of a P20A0 fault code may include:
- Poor engine performance
- Reduced fuel economy
- Check engine light on
What are some common causes of the code?
Causes
of this P20A0 code may include:
- Faulty reductant purge control valve
- Defective or damaged wiring
- Loose or faulty control module ground strap
- Corroded, damaged, or loose connector
- Blown fuse or fusible link (if applicable)
- Faulty PCM or ECM
What are the troubleshooting steps for P20A0?
The first step in the troubleshooting process for any malfunction is to check the technical service bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save you a lot of time in the long run by pointing you in the right direction.
The second step is to locate all components associated with the reductant purge control valve circuit and look for obvious physical damage. Depending on the specific vehicle, the DEF system may include several components, such as an electrically controlled reductant pump, a purge valve, a pressure sensor, an integrated level sensor, a temperature sensor, system heaters, filters, an electrically controlled reductant injector, and a tank. Perform a thorough visual inspection to ensure the associated wiring shows no obvious defects like scraping, rubbing, exposed wires, or burns. Then, check connectors and connections for security, corrosion, and damaged pins. This process should include all wiring connectors and connections to all components, including the PCM or ECM. Refer to vehicle-specific technical data to see if a fuse or fusible link is incorporated into the circuit.
Advanced Steps
Advanced steps become very vehicle-specific and require appropriate advanced equipment to operate accurately. These procedures require a digital multimeter and vehicle-specific technical references. In this situation, a pressure gauge may also be needed to facilitate the troubleshooting process.
Voltage Checks
Reference voltage and acceptable ranges can vary depending on the specific vehicle and circuit configuration. Specific technical data will include troubleshooting charts and the proper sequence to follow to help you make an accurate diagnosis.
If this process identifies a lack of power source or ground, continuity tests may be required to check the integrity of wiring, connectors, and other components. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings for wiring and connections should be 0 ohms of resistance. Resistance or lack of continuity indicates faulty wiring that is open or shorted and must be repaired or replaced. A continuity test between the PCM or ECM and the chassis will confirm the service level of ground straps and wires. The presence of resistance indicates a loose connection or possible corrosion.
What are the common repairs for this code?
- Replacing the reductant purge control valve
- Cleaning corrosion from connectors
- Repairing or replacing faulty wiring
- Replacing a blown fuse or fusible link (if applicable)
- Repairing or replacing faulty ground straps
- Flashing or replacing the PCM or ECM
Common Mistake
- Replacing the reductant purge control valve, associated DEF components, PCM, or ECM when faulty wiring is causing this code to set.
Hopefully, the information in this article has been helpful in guiding you in the right direction to fix the issue with your reductant purge control valve circuit error code. This article is strictly informational, and your vehicle-specific technical data and service bulletins should always take priority.