P1071

P1071

Diagnosis information - Control unit DME (DFI)

Mass air flow range near idle speed , implausible too high

Diagnostic conditions
- Idle speed > 30 s,
- then Engine speed > 1,500 1/min > 1 s ,
- then Idle speed > 30 s
- 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
- Oil filler cap lost
- Positive crankcase ventilation hose leaks (See [Information] 1)
- Intake system leaks - between Throttle valve and Engine (Intake valve)
- Tank vent Faulty - open
- Intake manifold pressure sensor - Electrical plug connection loose, oxidized, corroded, interrupted
- Fault in area Intake manifold pressure sensor, Throttle adjusting unit, Ambient pressure sensor, Intake air temperature sensor, Speed sensor, Valve lift control, Camshaft adjustment, Intake pipe switchover

Fault setting condition(s)
- Excessive deviation of the mass air flow within an engine operating period at the current idle compared to the last idle, at which the mass air flow was still within the tolerance range (e.g. hose fell off, ...). (See [Information] 2)

INFORMATION
1. - only Turbo
The following components are NOT tested during an overpressure test of the intake duct:
- Check valve for ventilation (Intake distributor distributor)
- Check valve for ventilation (Suction hose Turbocharger)
- Positive crankcase ventilation hose between Check valve for ventilation and Crankcase
- Crankcase

2. 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.