P1077

P1077

Diagnosis information - Control unit DME (DFI)

Mass air flow upper partial-load range, implausible too low

Diagnostic conditions
- Trip with different operating conditions
- none of the following faults stored: Intake manifold pressure sensor, Throttle adjusting unit, Ambient pressure sensor, Intake air temperature sensor, Speed sensor, Valve lift control, Camshaft adjustment, Intake pipe switchover

Possible fault causes
- Air cleaner soiled / Blocked / iced up
- Air intake (forward Air cleaner) Narrowed
- Air guide forward Throttle valve Blocked / Cross section Narrowed
- Exhaust system Blocked / Cross section Narrowed
- Intake pipe switchover Mechanical fault (if present present)
- Intake manifold pressure sensor - Electrical plug connection loose, oxidized, corroded, interrupted
- Fault in area Intake manifold pressure sensor sensor, Throttle adjusting unit unit, Ambient pressure sensor sensor, Intake air temperature sensor sensor, Speed sensor sensor, Valve lift control control, Camshaft adjustment adjustment, Intake pipe switchover

Fault setting condition(s)
- Impermissibly large deviation of the measured air mass from the calculated air mass. (See INFORMATION)

INFORMATION
In this diagnosis, the intake system between the throttle valve and the engine (intake valves) is monitored.
- A mass air flow is calculated from the signals from the throttle potentiometer, engine speed sensor, intake air temperature sensor and ambient pressure sensor as well as other engine operating values.
- The calculated mass air flow is compared with that measured by the pressure sensor.
- A deviation may be due to both the calculated mass air flow and the measured mass air flow.