P00F2

Mass Air Flow Sensor A Circuit High

P00F2 is a generic OBD-II powertrain diagnostic trouble code: Mass Air Flow Sensor A Circuit High. 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
P00F2
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P00F2 means

P00F2 is a generic powertrain code set when the Engine Control Module (ECM) detects an open or out-of-range condition on the intake air humidity sensor circuit. The humidity sensor measures moisture content in the incoming air, and the ECM uses this data to refine the air-fuel calculation, ignition timing, and on some vehicles combustion and emissions control such as NOx modelling on diesels and cold-start strategies. When the returned signal indicates an open circuit or an implausible value that does not track expected conditions, the ECM stores P00F2 and illuminates the MIL.

Typical causes are an open in the signal or ground wiring, a disconnected or corroded connector, or an internally failed humidity sensor. Because the sensor is frequently integrated into a combined intake air temperature and humidity module or mounted in the air intake, connector and harness faults are the most common real-world triggers. Contamination or moisture inside the connector can also break the circuit.

Drivability effects are usually minor: the ECM falls back to a default humidity assumption, so most drivers notice only the warning light and perhaps a slight change in fuelling or emissions readiness. Diagnosis should start with reading live humidity data and inspecting the wiring and connector before replacing the sensor, since wiring faults mimic sensor failure.

Common causes

Most-frequently reported root causes when P00F2 is logged.

  • 1
    Open circuit in the humidity sensor signal or ground wire.
  • 2
    Disconnected, loose, or corroded sensor connector.
  • 3
    Internally failed humidity sensor element.
  • 4
    Moisture or contamination inside the sensor connector.
  • 5
    Damaged wiring harness in the intake area causing an intermittent open.
  • 6
    Faulty integrated intake air temperature and humidity module.
  • 7
    Loss of reference voltage supplied to the sensor.

Symptoms drivers notice

Check engine light on with P00F2 stored.
Scan tool shows a missing, fixed, or implausible humidity reading.
Minor changes in fuelling or emissions behaviour.
Possible readiness monitor not completing.
Often no noticeable driver-perceived performance change.

How to diagnose P00F2

A typical diagnostic flow when this code is present.

  1. 1
    Read all codes and view the live humidity sensor value with a scan tool.
  2. 2
    Inspect the sensor connector and harness for corrosion, moisture, or damage.
  3. 3
    Verify reference voltage and ground at the sensor connector.
  4. 4
    Check the signal wire for an open between the sensor and the ECM.
  5. 5
    Confirm the reading responds plausibly to ambient conditions if the sensor is live.
  6. 6
    Replace the sensor only after wiring checks pass, then clear codes and retest.

Related powertrain codes

Frequently asked questions

What is P00F2 really about?

It flags an open or out-of-range fault in the intake air humidity sensor circuit, not the mass air flow sensor.

Why does the engine need a humidity sensor?

Air moisture affects air density and combustion, so the ECM uses humidity data to fine-tune fuelling, timing, and emissions strategies.

Will P00F2 hurt drivability?

Usually only slightly, because the ECM substitutes a default humidity value, but the fault should be repaired for accurate control and emissions readiness.

Is the sensor separate or combined?

On many vehicles the humidity sensor is integrated with the intake air temperature sensor, so a connector or module fault can affect both readings.

Disabling P00F2 in software

RaceTune can permanently disable P00F2 — 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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