P22FA

Turbocharger/Supercharger Boost Control A - Actuator Stuck Open

P22FA is a generic OBD-II powertrain diagnostic trouble code: Turbocharger/Supercharger Boost Control A - Actuator Stuck Open. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P22FA
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on, possible limp mode)
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What P22FA means

P22FA is stored when the ECM determines that the boost control actuator for turbocharger or supercharger circuit A is stuck in the open (low-boost or wastegate-open) position. The ECM commands the actuator to close or partially close to build boost pressure, but the feedback and/or manifold pressure sensors indicate that boost is not building as expected, consistent with an actuator that remains open.

This condition typically results in noticeably reduced turbo boost, sluggish performance, and poor fuel economy because the engine cannot develop the intended charge pressure. The root cause is often a mechanically seized actuator, a ruptured boost control solenoid diaphragm, or a vacuum/pneumatic leak in the control circuit. Electrical faults such as an open-circuit solenoid winding can produce the same symptom from the ECM perspective.

Because boost pressure is lower than commanded rather than dangerously elevated, P22FA rarely triggers a critical limp mode, but power reduction strategies are common. Diagnosis should start with verifying the actuator control solenoid operation and then progressing to mechanical inspection of the actuator linkage and wastegate/bypass valve itself.

Common causes

Most-frequently reported root causes when P22FA is logged.

  • 1
    Mechanically seized or corroded boost control actuator unable to close.
  • 2
    Ruptured or leaking actuator diaphragm allowing it to default to the open position.
  • 3
    Failed boost control solenoid with an open winding preventing vacuum/pressure actuation.
  • 4
    Vacuum or boost reference hose disconnected, cracked, or kinked.
  • 5
    Sticking wastegate flap or bypass valve due to carbon deposits.
  • 6
    Open circuit or broken wire in the boost control solenoid electrical circuit.
  • 7
    Faulty ECM output driver for the actuator control circuit.

Symptoms drivers notice

Reduced engine power and poor throttle response under load.
Turbo boost pressure noticeably lower than expected.
MIL illuminated with possible restricted performance mode active.
Poor fuel economy due to insufficient charge pressure.
Possible whistling or hissing from a vacuum or boost hose leak.

How to diagnose P22FA

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all DTCs and freeze-frame data with a scan tool.
  2. 2
    Monitor boost pressure live data and compare to commanded boost at various RPMs.
  3. 3
    Inspect all vacuum and boost reference hoses connected to the actuator for cracks or disconnections.
  4. 4
    Test the boost control solenoid resistance and verify it matches specification.
  5. 5
    Apply a controlled vacuum or pressure to the actuator directly to check mechanical movement.
  6. 6
    Check solenoid power supply and ground circuit continuity at the connector.
  7. 7
    If the actuator diaphragm is ruptured or the solenoid is open-circuit, replace the affected component and retest.

Related powertrain codes

Frequently asked questions

What does stuck open mean for a boost actuator?

It means the valve controlling boost build-up remains in the position that prevents pressure from rising, so the engine produces less power than normal.

Can a split vacuum hose cause P22FA?

Yes. A cracked or disconnected vacuum hose is one of the most common causes and is an inexpensive first item to inspect.

Is P22FA the same as P22FF?

P22FF typically indicates the actuator is stuck closed (over-boost), whereas P22FA indicates stuck open (under-boost); the diagnostic approaches differ accordingly.

Will the engine be damaged if I keep driving?

Low boost is less immediately dangerous than over-boost, but running with reduced power for extended periods can cause excessive fueling or thermal issues; prompt diagnosis is recommended.

Disabling P22FA in software

RaceTune can permanently disable P22FA — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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