OBD Guide

P20A9

Reductant Injection Air Pressure Control Valve Circuit High

P20A9 is an OBD-II diagnostic trouble code meaning: Reductant Injection Air Pressure Control Valve Circuit High. Common causes: short circuit in valve circuit, air pressure control valve malfunction. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Check Engine Light Is On
  • Reduced engine power
  • Increased urea consumption (AdBlue)
  • Increased NOx emissions
  • SCR system error message on dashboard

Causes

  • Short circuit in valve circuit
  • Air pressure control valve malfunction
  • Broken or damaged wiring
  • Problems with the SCR control unit
  • Corrosion of contacts or connectors

How to Fix

  1. Check the integrity of wiring and connectors
  2. Measure valve resistance
  3. Check control circuit voltage
  4. Replace faulty valve if necessary
  5. Reset the error and check the system operation

Related codes

Error P20A9 by Vehicle Brand

FAQ

What does the P20A9 code mean?

P20A9 is an OBD-II diagnostic trouble code that indicates: Reductant Injection Air Pressure Control Valve Circuit High

What causes a P20A9 error code?

The most common causes of P20A9 include: Short circuit in valve circuit; Air pressure control valve malfunction; Broken or damaged wiring; Problems with the SCR control unit.

How do I fix a P20A9 diagnostic trouble code?

To fix P20A9: Check the integrity of wiring and connectors. Measure valve resistance. Check control circuit voltage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P20A9?

Yes, but get it checked soon

How much does it cost to fix P20A9?

The estimated repair cost for P20A9 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat