Checking Signal And Ground Wires

-- Connect test box (VAG1598/42) to Engine Control Module (ECM) -J623- wiring harness using adapter cable (VAG1598/39-2), connecting test box for wiring test.

-- Check wires between test box and harness connector for open circuit according to wiring diagram.

Fig 1: Identifying 5-Pin Electrical Harness Connector & Terminals

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Terminal 2+socket 18

Terminal 3 + socket 60

Terminal 4 + socket 40

Terminal 5 + socket 82

Wire resistance: max. 1.5Ω

-- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.

Specified value: ∞ Ω

If no malfunctions are found in wires:

-- Replace Engine Control Module (ECM) -J623- ENGINE CONTROL MODULES, REPLACING .

Mass Air Flow Sensor 2, Test Sequence

Function Test

-- Connect diagnostic tester.

-- Start engine and let run at idle.

-- Depress accelerator pedal to approx. 1500 RPM.

-- Under address word 33, select "Diagnostic mode 1: Check 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:

Specified value: 4.50 to 7.00 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.

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 .

Checking Voltage Supply

-- Disconnect 5-pin connector from Mass Air Flow (MAF) Sensor 2 -G246- (-A-).

Fig 2: Identifying Connector For Mass Air Flow (MAF) Sensor 2 G246 And Intake Air Temperature (IAT) Sensor 2 G299

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Switch ignition on.

-- Measure voltage supply for MAF sensor between the following connector terminals:

Fig 3: Identifying 5-Pin Electrical Harness Connector & Terminals

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Connector on Mass Air Flow (MAF) Sensor 2 -G246- Terminal		Specified value:
2 + Ground (GND)		approx. battery voltage
2 + 3		approx. battery voltage
4 + Ground (GND)		approx. 5 V
4 + 3		approx. 5 V

-- Switch ignition off.

If specified values are obtained:

-- Replace Mass Air Flow (MAF) Sensor 2 -G246-.

-- Erase DTC memory of Engine Control Module (ECM) DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .

-- Generate readiness code READINESS CODE .

If specified values are not obtained:

-- Check signal and Ground (GND) wires of Mass Air Flow (MAF) sensor.