What Does P20A2 Mean?
The PCM has detected an abnormally low voltage condition in the reductant purge control valve circuit. This indicates a short to ground or excessive current draw in the valve circuit.
Common Causes
35%
Short circuit to ground in wiring harness
30%
Failed purge valve with internal short circuit
20%
Damaged or pinched wires near valve or chassis
10%
Water intrusion causing short in connector or valve
5%
Failed PCM driver circuit
Diagnostic Steps
1
Step 1: Disconnect purge valve connector and check for voltage drop to verify short location
2
Step 2: Measure resistance between valve circuit wires and ground with valve disconnected
3
Step 3: Inspect wiring harness routing for pinch points, abrasion, or heat damage
4
Step 4: Test purge valve resistance and check for internal short to case ground
5
Step 5: Check for moisture or corrosion in connectors that could cause intermittent shorts
Estimated Repair Cost
$150 - $850
Parts + labor, varies by vehicle and location
The PCM has detected an abnormally low voltage condition in the reductant purge control valve circuit. This indicates a short to ground or excessive current draw in the valve circuit.
The most common cause of P20A2 (Reductant Purge Control Valve Circuit Low) is: Short circuit to ground in wiring harness
Typical repair costs for P20A2 range from $150 to $850, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive temporarily but may experience reduced power mode. Electrical short could potentially cause further wiring damage if not repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P20A2 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Emissions Control System (SCR/DEF)
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
