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TuningBot DTC Database · v4.37.15

P20A9 Reductant injection air pressure control valve - circuit high

Generic (OBD-II) interpretation in the TuningBot DTC database.

P · PowertrainEmissionsOBD2

What P20A9 means

P20A9
Reductant injection air pressure control valve - circuit high Generic · emissions Data confidence 78%

The control module detected that the signal in the Reductant injection air pressure control valve circuit stayed above the expected operating range.

Symptoms

  • MIL or SCR/AdBlue warning illuminated
  • Possible start-count-down or torque limitation on some applications

Possible causes

  • Wiring
  • reductant injection air pressure control valve
  • ECM

Recommended checks

  • Read NOx sensor values and dosing system status
  • Check reductant level and quality data
  • Inspect dosing valve, lines and heater operation
  • Check wiring and connectors of the SCR components
  • Check for OEM technical bulletins and software updates

Related and nearby codes

How to read P20A9

P

Powertrain: engine, transmission and driveline systems.

2

Generic SAE-standard code: same meaning on every make.

0A9

Specific fault index within the subsystem.

Frequently asked questions about P20A9

What does P20A9 mean?

Reductant injection air pressure control valve - circuit high. The control module detected that the signal in the Reductant injection air pressure control valve circuit stayed above the expected operating range.

Is P20A9 generic or manufacturer-specific?

P20A9 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove P20A9 at file level?

If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry. Checksum correction is not included: it is a separate, optional service. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.

Other file services

ECU tuningDyno-tested results by model and engine See the results →

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