P20A3Reductant Purge Control Valve A Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P20A3 is the high-side fault of the purge valve circuit: the line carries voltage or current where it should not. GM detects it on the 6.6 L Duramax while the low-side driver is switched on; an impedance of less than 0.5 Ω to controller power lasting 3 s triggers it as a Type A fault. Volkswagen's test for the 2014 Touareg V6 TDI (engine CNRB) looks at current instead and reports P20A3 above 3.00 A, which indicates a short across the coil or to battery positive. A driver that sees such overcurrent switches off to protect itself, so the valve no longer reverses the pump, and the line is not emptied at shutdown. P20A2 covers the opposite short to ground and P20A0 the open circuit. Look for a shorted coil, a wire touching a supply cable or a damaged connector at the supply module.
- What you may notice
- MIL on in the first trip (GM Type A)
- DEF warning and possibly further pump codes
- In frost, risk of DEF freezing in the line
- Likely causes
- LikelyValve coil with shorted windings drawing excessive current
- PossibleControl wire shorted to a battery-fed conductor
- PossibleDamaged or DEF-contaminated connector bridging pins
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.