P0101

P0101

Mass Air Flow Circuit. Performance Problems.







Fault symptoms
- CHECK ENGINE.

On-Board Diagnostics

Type of diagnosis:
- Continuous. Terminated when fault criteria fulfilled. Restarts next driving cycle.

Enable criteria:
- General conditions for this trouble code: Atmospheric pressure must exceed 72 kPa and the engine coolant and intake air temperature must be above -70 degree C.
- Main relay voltage exceeds 10 V. Vehicle speed over 45 km/h for longer than 60 s accumulated time. Coolant temperature between 78 and 115 degree C. Engine speed between 700 and 4000 rpm. Purging active. No fuel shut-off. No change in bypass valve status. Pressure ratio before and after throttle between 0.2 and 0.7. Throttle opening between 50 and 500 square mm. Even engine load.
- Mass air flow is calculated using the throttle opening and pressure difference before and after the throttle.

Fault criteria:
- Conditions for test 1, 2, 3 or 4 fulfilled.
- Test 1: Mass air flow sensor indicates value more than 12% lower than the calculated while the multiplicative adaptation is higher than 17%.
- Test 2: Mass air flow sensor indicates value more than 12% higher than the calculated while the multiplicative adaptation is lower than -17%.
- Test 3: Mass air flow sensor indicates value more than 30% lower than the calculated.
- Test 4: Mass air flow sensor indicates value more than 30% higher than the calculated.

Dependents:
- P0112, P0113, P0106, P0107, P0108, P1105, P1106, P1107, P1108, P1230, P0501, P0502, P1625, P0444, P0445.

System reaction to a fault:
- Fuel adaptation reset. Intake pressure and intake air temperature used as substitute values.

OK report:
- Enable criteria fulfilled without any faults being reported.

Fault handling: (For more information, Fault Handling III, Other Emission-Related Components and Function)

- Type III.

Diagnostic help
The diagnostic trouble code indicates a leak between the mass air flow sensor and throttle body or a fault in the mass air flow sensor.

Functions in the diagnostic tool related to the fault:
- Diagnostic status for the diagnosis.
- Air mass deviation from calculated, unit %.