What are the common causes of P20A5?

A reductant purge control valve A stuck closed. Urea crystal buildup plugging the valve. A failed reductant purge control valve A. A clogged purge passage.

Command the reductant purge control valve A with a scan tool. Check for urea crystal buildup at the valve. Verify the valve opens when commanded. Inspect the purge passage for a clog. Replace the reductant purge control valve A if it stays closed. Clear the code and retest.

P20A5

Reductant Purge Control Valve A Stuck Closed

System: Fuel and air metering (P code)
Lamp: Check Engine Light
Category: Powertrain - Fuel/Air Metering

What it means

P20A5 means Reductant Purge Control Valve A Stuck Closed.

Where it lives

For P20A5, start at the valve the description names.

Check these first

A reductant purge control valve A stuck closed
Urea crystal buildup plugging the valve
A failed reductant purge control valve A
A clogged purge passage

What to do next

Command the reductant purge control valve A with a scan tool
Check for urea crystal buildup at the valve
Verify the valve opens when commanded
Inspect the purge passage for a clog
Replace the reductant purge control valve A if it stays closed
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.