Conditions

Mass Air Flow Circuit. No Signal.





Fault symptoms
- CHECK ENGINE comes on after two driving cycles.
- Engine speed drops slower than normal when the accelerator is released.
- Possible misfiring before DTC is generated.

On-Board Diagnostics

Type of diagnosis:
- Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.

Enable criteria:
- Crankshaft rotating. Main relay voltage above 10 V.

Fault criteria:
- No frequency for more than 0.5 s.

Dependents:
- None.

System reaction to a fault:
- Fuel adaptation reset. Intake pressure and intake air temperature used as substitute values.

OK report:
- 60 s has past since start. Fault criteria for P0100, P0102 or P0103 not fulfilled.
- Conditions for multiplicative fuel adaptation fulfilled. Mass air flow sensor value corresponds with both the air mass flow calculated from intake manifold pressure and the air mass flow calculated from throttle position.

Fault handling: Fault Handling III, Other Emission-Related Comp. & Function
- Type III.

Diagnostic help
Fault diagnosis concerns electrical faults in connected leads or in the sensor.

Diagnostic tool functions related to this fault are:
- Diagnostic status for the diagnosis.
- Mass air flow sensor reading, in g/s.
- Airmass deviation from calculated, in %.

See also the description of test values under "Fault diagnosis, general" for more information. Tech 2 Menu Structure, DTC Menu, Read Value, Activate, Sys Info

Check the wiring
Jiggle the leads and in-line connectors at various points and in different directions to detect any intermittent breaks or short circuit in the wiring. Observe the Multimeter, test lamp or diagnostic tool while doing this.

Proceed to Diagnostic Procedures. Checking the Sensor's Power Supply