P1094
P1094Diagnosis information - DME (DFI)
Implausible mass air flow ahead of throttle valve
NOTE:
- The fault P1094 [Implausible mass air flow ahead of throttle valve] indicates that a mass air flow deviation from the calculated model has been detected between the hot-film mass air flow (MAF) sensor and the throttle valve in at least one load range.
- An initial indication appears because the corresponding fault(s) is/are stored.
NOTE:
- 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 mass air flow (MAF) sensor.
- Any deviation may be due to both the calculated mass air flow and the measured mass air flow.
NOTE:
- A throttle valve for which forced adaptation was carried out under the wrong conditions (e.g. intake air temperature more than 40 °C (104 °F)) can result in the fault entry.
- It is possible to establish in the extended fault memory whether the adaptation process is responsible for the fault entry.
- To do this, you must exit guided fault finding.
--> see fault memory for fault code P1094 under
--> [F8] NOTE
--> [F5] ENVIRONMENTAL CONDITIONS
--> Environmental conditions when fault first occurred
--> Environment 6 (last value) [STATE_TPS_AD_CDN_ENA]
A bit field is displayed (e.g.: [b 1----1-1]), the value of the last place is important:
- Value 1 ([b 1----1-1]) means that forced adaptation of the throttle valve was performed under the wrong conditions.
- Value - ([b 1----1- - ]) means that the throttle valve was adapted under the correct conditions.
Diagnostic conditions
- Throttle valve was adapted under the right conditions
(including: intake air temperature less than 40 °C (104 °F))
- Engine running
- No electrical fault for hot-film mass air flow sensor (MAF)
- No throttle valve adjusting unit fault
- No ambient pressure sensor fault
- No intake air temperature sensor fault
- No speed sensor fault
- No valve lift fault
- No camshaft adjustment fault
- No intake manifold switch-over fault
Possible fault causes
- Hot-film mass air flow (MAF) sensor soiled/faulty (displaced characteristic) (setpoint voltage with stopped engine and ignition on = 0.9 ... 1.1 V
--> see Actual values, Filter [H_Mass air flow flow], [H030_Mass air flow sensor 1 (sensor)])
- Forced adaptation of the throttle valve was performed under the wrong conditions
(e.g.: intake air temperature more than 40 °C (104 °F))
- Fault in the area of valve lift, camshaft adjustment, intake manifold, intake manifold switch-over, throttle valve, ambient pressure sensor, intake air temperature sensor, speed sensor
- Changed air flow to hot-film mass air flow (MAF) sensor due to:
- Foreign matter ahead of hot-film mass air flow (MAF) sensor
- Twisted hot-film mass air flow (MAF) sensor
- Leak just ahead of hot-film mass air flow (MAF) sensor
- Clogged air cleaners
- Exhaust system faulty - flow severely restricted
- Leakage between hot-film mass air flow (MAF) sensor and throttle valve adjusting unit
- Plug connection on the hot-film mass air flow (MAF) sensor oxidized / faulty.