With Manufacturer's Scan Tool

Mass Air Flow (MAF) sensor, checking

Special tools and equipment

- V.A.G 1551 Scan Tool (or VAG 1552 mobile scan tool) with VAG 1551/3 cable
- VAG 1598/31 test box
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 1594 connector test kit
- Wiring diagram

Test requirements






- Fuse no.34 must be OK.
- Coolant temperature must be at least 80 °C, See Display group 04, display field 3
- All electrical consumers like, for example, lights and rear window heating must be switched off.
- If vehicle is equipped with an A/C system, it must be switched off.
- For vehicles with automatic transmission, selector lever must be in -P- or -N-.

Test sequence

- Connect V.A.G 1551 scan tool (VAG 1552). Start engine and select the Engine Control Module (ECM) using address word 01. [1][2][3]Connecting VAG 1551 Scan Tool

Indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- to select "Read measuring value block" function 08. Press -Q- button to confirm input.

Indicated on display


Read Measuring Value Block HELP
Input display group number XXX


- Press 0, 0 and 2 for function "display group number 2", and then press Q to exit from input mode.

Indicated on display (1 - 4 = display fields)


Read Measuring Value Block 2 ->
1 2 3 4


- Check mass flow of air into engine in display field 4

Specification: 3.0 - 5.0 g/s

If expected 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 wires of Mass Air Flow (MAF) sensor.

If the specified value is met:
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06. Press -Q- button to confirm input.
- Switch ignition off.

Checking Voltage Supply for Mass Air Flow (MAF) Sensor

- Start engine, and let it idle.







- Pull 4-way connector oft Mass Air Flow (MAF) sensor.
- Connect multimeter to terminal 3 of connector and engine Ground (GND) to make voltage measurement.

Specification: 11-15 V


NOTE: Voltage is supplied to Mass Air Flow (MAF) sensor from Fuel Pump (FP) relay.


If there is no voltage:
- Switch ignition off.
- Check wire connection from terminal 3 to Fuel Pump (FP) relay (J17) (see wiring diagram).

If voltage supply and wires are in order:
- Switch ignition on.
- Connect multimeter to terminals 2 and 3 of connector to make voltage measurement.

Specification: 4.5-5.5 V

If there is no voltage:
- Switch ignition off.
- Check signal and ground wires.

Checking Signal and Ground Wires for Mass Air Flow (MAF) Sensor







- Connect VAG 1598/31 test box to control module wiring harness. Engine Control Module (ECM) is not connected.







- Check for breaks in wires between test box and 4-way connector (see wiring diagram).

Terminal 1 + socket 53
Terminal 2 + socket 27
Terminal 4 + socket 29

Wire resistance: max. 1.5 Ohms

- Also check wires for shorts among one another.
- Also check wires for shorts to battery B+ or Ground (GND).

If no DTCs are found in wires:
- Replace Mass Air Flow (MAF) sensor -G70- item 7