P1100

P1100

Mass Air Flow Ahead Of Throttle Valve Implausible (too High)

Diagnostic conditions
- Supply voltage 10 V ... 16 V
- Engine start
- No faults detected for throttle valve adjusting unit, ambient pressure sensor, intake temperature sensor, speed sender

NOTE: In this context, please also observe the function description.

Possible fault causes
- Hot-film mass air flow meter faulty (battered)
- DME control module faulty (ambient pressure sensor at fault detection threshold)

Mass air flow upstream of throttle valve implausible (too low)

Diagnostic conditions
- Power supply voltage 10 V ... 16 V
- Engine start
- No faults detected for throttle valve adjusting unit, ambient pressure sensor, intake temperature sensor, speed sender

NOTE: In this context, please also observe the function description.

Possible fault causes
- Air cleaner blocked
- Leakage between MAF sensor and throttle valve adjusting unit
- Throttle valve sluggish or heavily soiled
- MAF sensor faulty (battered)
- One or both cylinder banks remain jammed in small valve lift
- DME control module faulty (ambient pressure sensor at fault detection threshold)

Function description

Diagnosis of plausibility of MAF sensor signal

- The measured value supplied by the MAF sensor is compared to a value from a map. This map is determined by engine speed, throttle valve position, ambient pressure and intake air temperature.
- The mass air flow upstream of the throttle valve is identified as implausible if the measured value deviates too greatly from the map.
- If the switching cups stick on a small stroke on one or both banks (e.g., oil duct blocked), the MAF sensor can also be detected as faulty. This is because the expected increase in the air-flow rate does not occur.
- The monitoring of electrical faults (open circuit, short circuit) takes place in a separate diagnosis.