Function test

• Connect diagnostic tester. Refer to Diagnostic tester, connecting  .
• Start engine and let run at idle.
• Under address word 33, select "Diagnostic mode 1: Checking measured values."
• Select the measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor".

• Check specified value of air flow quantity at Mass Air Flow (MAF) Sensor at idle:

Vehicles with engine code ALH:

Specified value: 2.80 to 5.30 g/sec

Vehicles with engine code BEW:

Specified value: 1.80 to 4.30 g/sec

• End diagnosis and switch ignition off.

If specified value is obtained, but DTC memory has a DTC concerning Mass Air Flow (MAF) sensor:

• Check voltage supply of Mass Air Flow (MAF) sensor. Refer to Voltage supply for Mass Air Flow (MAF) sensor, checking  .

If specified value is not obtained:

• Check signal and Ground (GND) wires of Mass Air Flow (MAF) sensor. Refer to Checking signal and Ground wires of Mass Air Flow (MAF) Sensor  .