P0101

PO1O1

Hot-film Mass Air Flow Sensors (MAF) - Signal Implausible

Diagnostic conditions
- Battery voltage between 10 V and 16 V
- Engine running
- Relatively long drive in all load ranges

Possible fault cause
- Hot-film mass air flow sensor 1 and / or 2 faulty (setpoint voltage with stopped engine and ignition on = 0.9 to 1.1 V)=> see Actual values, Filter [ DME mass air flow ], [ Mass air flow 1 (sensor) ] + [ Mass air flow 2 (sensor) ]
- Throttle valve stiff or [ blocked ]
- Secondary air between hot-film mass air flow sensor and throttle valve (e.g. crack in hose)
- Throttle valve adjusting unit faulty
- Turbo only: Intake air temperature sensor faulty (in boost pressure sensor)
- Naturally aspirated engines only: Intake air temperature sensor faulty (in hot-film mass air flow sensor)
- DME faulty (pressure sensor for ambient air pressure)

Diagnosis/fault finding







Hot-film mass air flow sensor







Boost pressure sensor

- For this fault code, the intake system between the hot-film mass air flow sensors and the throttle valve is monitored.
- The pressure sensor for ambient air pressure is installed in the engine control unit.
- If the connector A is disconnected from the DME control unit and the ignition is switched on or was switched on, the fault [ DME control unit TIMEOUT ] is entered in many control units.
- If the control unit connector A was disconnected from the DME during fault finding or if the power supply was interrupted elsewhere (battery, fuse), adaptation of the throttle valve adjusting unit must be performed.
- Both of the hot-film mass air flow sensors must be checked.
- Adaptation [ RKAT ] is additive, remains unadapted at ± 0.0%.
- Adaptation [ FRAU ] is multiplicative, remains unadapted at + 1.00

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