P20A0: Reductant Purge Control Valve A Circuit/Open
The reductant purge control valve A drive circuit is open — used to evacuate DEF lines back to the tank when the engine is shut down to prevent freezing damage.
What P20A0 means
P20A0 is a generic OBD-II powertrain code in the emissions group. In plain English: the computer found an electrical fault in that circuit: an open, short or bad connection, or a failed component.
- Check engine light
- Usually on
- Emissions-related
- Yes — can fail inspection
- Limp mode possible
- Not typical
- Drive cycle to clear
- Not required
Get it fixed
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Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
Common causes
- 01Solenoid winding openMost likely
- 02Pin pushed back out of connector bodyLess likely
- 03Cracked solder joint inside the module or sensorLess likely
Can I drive with P20A0?
Generally yes.
This fault is unlikely to affect how the car drives, but it will usually fail an emissions inspection. Fix it when convenient.
Why we rate it low
- Turns on the check engine light
- Emissions-related: will usually fail an OBD inspection
- EVAP leaks rarely affect how the car drives
Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.
How to diagnose P20A0
- 1
Confirm the code and save freeze-frame data
Read the codes with an OBD-II scan tool and note every code, not just P20A0. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.
- 2
Fix other faults first
If other codes are stored, start with power-supply, sensor-circuit and communication codes. They can cause this code as a side effect.
- 3
Test the circuit
Inspect the wiring and connector at the reductant purge valve for damage, corrosion or chafing. With a multimeter, check supply voltage, ground and signal against the specifications in the service manual for your vehicle.
- 4
Test the likely causes in order
Start with the most likely cause and work down: Solenoid winding open; pin pushed back out of connector body; cracked solder joint inside the module or sensor. Test before replacing parts.
- 5
Check for recalls and service bulletins
Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.
- 6
Clear the code and verify the repair
After the repair, clear the code and drive the car under the conditions in the freeze-frame data to confirm it does not return.
P20A0 repair cost estimate
Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.
- DIY difficulty
- Moderate
- Good DIY job?
- Usually a shop job
Needs a scan tool and some experience with testing.
Parts and systems involved
- Reductant purge valve
P20A0 FAQ
What does P20A0 mean?
P20A0 means “Reductant Purge Control Valve A Circuit/Open”. The reductant purge control valve A drive circuit is open — used to evacuate DEF lines back to the tank when the engine is shut down to prevent freezing damage.
Is P20A0 serious? Can I keep driving?
We rate P20A0 as low severity. Generally yes. This fault is unlikely to affect how the car drives, but it will usually fail an emissions inspection. Fix it when convenient.
What causes P20A0?
The most common causes, from most to least likely: Solenoid winding open; Pin pushed back out of connector body; Cracked solder joint inside the module or sensor. Test before replacing parts, because several causes can set the same code.
How much does it cost to fix P20A0?
Typical labor is about $90–$315 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.
Can I fix P20A0 myself?
DIY difficulty is moderate. Most owners leave this to a shop because it needs involved testing or specialist tools. Always confirm the cause before buying parts.
Will P20A0 clear itself?
If the fault was intermittent, the warning may go off once the computer stops seeing it, but the code stays in memory. Fix the cause; clearing the code alone doesn’t repair anything.