P1072

P1072

Diagnosis information - Control unit DME (DFI)

Mass air flow range near idle speed, implausible too high

Diagnostic conditions
- Idle speed more than 2 Minute(s)
- 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
- Oil filler cap was opened while engine was running
(e.g. to top up oil)
(See Environmental condition 6 for first fault occurrence [SE10 Engine compartment lid open])
- Oil filler cap leaks
- Throttle valve adaptation performed while boundary conditions are violated.
(See INFORMATION 3)
- 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)
- Impermissibly large deviation of the measured air mass from the calculated air mass. (See INFORMATION 2)

INFORMATION
1. The following components are NOT tested during an overpressure test of the intake duct:
- Check valve for ventilation (Suction hose Turbocharger) --> See Installation position [A]
- Check valve for ventilation (Intake distributor) --> See Installation position [B]
- Positive crankcase ventilation hose between Check valve for ventilation and Crankcase --> See Installation position [C]
- 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.

3. A note to this effect is stored in the environmental data for the fault entry value [XX-Status of throttle adaptation conditions].
- The value indicates whether the throttle valve was taught under violated boundary conditions.
- 0 ... 127 = Throttle valve was taught under the correct boundary conditions.
- 128 ... 255 = Throttle valve was taught under violated boundary conditions.