With Manufacturer's Scan Tool
Mass Airflow (MAF) Sensor, Checking
NOTE: Only gold-plated contacts can be used to repair contacts in the connector for the Mass Air Flow (MAF) sensor.
Special tools, test equipment and auxiliary items
- Scan tool V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3B
- Test box V.A.G 1598/31
- Hand multimeter V.A.G 1526 or multimeter VAG 1715
- Adapter set V.A.G 1594
- Wiring diagram
Check conditions
- Fuse 43 must be OK
- The battery voltage must be at least 11.5 V
- Fuel pump relay must be OK
- All electrical consumers, e.g. lights and rear window heating must be switched off
- If the vehicle is equipped with an air conditioner, this must be switched off
- On vehicles with automatic gearbox selector lever in "P" or "N" position
- Coolant temperature must be at least 85 °C, see display group 04, display zone 3
Test sequence
- Connect scan tool V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control module. When doing this the engine must be running at idle speed. (Connecting scan tool and selecting engine control module). Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAG 1551 Scan Tool", Testing and Inspection
Indicated on display
Rapid data transfer HELP
Select function XX
- Press keys 0 and 8 for the function "Read measuring value block" and confirm entry with Q key.
Indicated on display
Read measuring value block
Input display group number XXX
- Press keys 0, 0 and 2 for "Display group number 2" and confirm entry with Q key.
Indicated on display (1-4 = Display zones)
Read measuring value block 2 ->
1 2 3 4
- Check the air mass drawn in in display zone 4.
Display Group 2:
If the specification is attained:
- Press -> key.
- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
- Switch off ignition.
Evaluating display group 2, display zone 4 - Air mass drawn in
Testing power supply to Mass Air Flow (MAF) sensor
- Pull 5 pin connector -1- off Mass Air Flow (MAF) sensor (G70) arrow.
- Connect multimeter to measure voltage on connector contact 2 and engine Ground.
- Start engine and run at idle speed.
Specification: 11.0 - 15.0 V
If no voltage is present:
- Switch off ignition.
- Check wire between 5-pin connector contact 2 and fuel pump relay (J17) for open circuit using wiring diagram.
Wire resistance: max. 1.5 Ohms
If the voltage supply and wiring is OK:
- Connect multimeter to measure voltage on connector contact 4 and engine Ground.
- Switch on ignition.
Specification: min. 4.5 V
If no voltage is present:
- Switch off ignition.
- Check the signal and Ground wires.
Testing signal and Ground wires for Mass Air Flow (MAF) sensor
- Remove inner plenum chamber cover, left:
- Connect test box V.A.G 1598/31 to control module wiring harness. The engine control module is not connected by this action.
- Check wiring for open circuit between test box and 5-pin connector using wiring diagram.
- Contact 5 + socket 29
- Contact 4 + socket 53
- Contact 3 + socket 27
Wire resistance: Max. 1.5 Ohms
- Additionally check wires all for short to one another.
Specification: Infinity Ohms
- Check wiring additionally for short circuit to battery positive/Ground.
NOTE: Socket 1 in Mass Air Flow (MAF) sensor and connector is not occupied.
If no wiring problem is detected:
- Replace Mass Air Flow (MAF) sensor (G70), item 2.
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory, checking and erasing DTC memory. Refer to "Displaying, Reading and Erasing Trouble Codes/With Manufacturers Scan Tool/DTC Memory, Checking And Erasing", Testing and Inspection
- Read-out the readiness code. If the DTC memory has been erased or the engine control module was disconnected from permanent positive, the readiness code must be generated again.
Refer to "Monitors Trips and/or Drive Cycle/Displaying Readiness Code", Testing and Inspection
Refer to "Monitors Trips and/or Drive Cycle/Generating Readiness Code", Testing and Inspection