3.2.359. SPN 520391, FMI 31, Air mass sensor start test value not plausible (too high)ΒΆ

Description

The EEM monitoring system has detected that the air mass sensor mass flow value is implausible.

Possible causes are:

  • The sensor wiring contact is loose.
  • The sensor wiring is defective.
  • The sensor is defective.
  • Dirt in the venturi tube or other significant changes in the air pipe lines.

Reaction in EEM

The FC is stored and the warning lamp is activated. The CAN message indicates active fault.

Solution

First save the error log and then erase it. Restart the ECU after erasing the error log. If the fault occurs again during the next driving cycle, check the following paths:

  • Check the air mass sensor wiring, the connectors and the contact surfaces of the connector pins (possible oxidation).
  • Check that the venturi tube is clean and not squashed.
  • Check the operation with another air mass sensor to see if the sensor is defective.

See Airmass sensor for reference.