With Manufacturer's Scan Tool
Mass Air Flow (MAF) Sensor -G70-, Checking
NOTE: Only gold-plated terminals can be used to repair terminals in the connector for the Mass Air Flow (MAF) sensor -G70-.
Special tools and equipment
- Scan tool VAG 1551 or vehicle system tester V.A.G 1552 with cable VAG 1551/3B
- Test box V.A.G 1598/31
- Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
- Adapter set V.A.G 1594
- Wiring diagram
Check conditions
- All fuses must be OK
- Coolant temperature must be at least 85 °C, see display group 04, display zone 3
- The battery voltage must be at least 11.5 V
- 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 transmission selector lever in "P" or "N" position
Test sequence
- Connect scan tool VAG 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control module. When doing this engine must be running at idle speed.
Connecting scan tool and selecting engine control module. [1][2][3]Connecting VAG 1551 Scan Tool
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons 0 and 8 for function "Read Measuring Value Block" and confirm entry with Q button.
Indicated on display
Read Measuring Value Block
Input display group number XXX
- Press buttons 0, 0 and 2 for "Display group number 2" and confirm entry with Q button.
Indicated on display (1-4 = Display zones)
Read Measuring Value Block 2 ->
1 2 3 4
- Check mass of air drawn in in display zone 4
Specification: 2.0 to 5.0 g/s
- If value is as specified but DTC memory has recorded a DTC relating to Mass Air Flow (MAF) sensor, check voltage supply for Mass Air Flow (MAF) sensor.
If the specification is not obtained:
- Check signal and Ground wires of Mass Air Flow (MAF) sensor.
If the specification is attained:
- Press -> button.
- Press buttons 0 and 6 for function "End output" and confirm entry with Q button.
- Switch ignition off.
Testing power supply to Mass Air Flow (MAF) sensor
- Disconnect 5 pin connector oft Mass Air Flow (MAF) sensor (G70) -arrow-.
- Connect multimeter to measure voltage on connector terminal 2 and engine Ground.
- Start engine and run at idle speed.
Specification: 11.0-15.0 V
If no voltage is present:
- Switch ignition off.
- Check wiring between terminal 2 and fuel pump relay (J17) using wiring diagram.
If the voltage supply and wiring are OK:
- Connect multimeter to measure voltage on connector terminal 4 and engine Ground.
- Switch ignition on.
Specification: 4.5 to 5.5 V
If no voltage is present:
- Switch ignition off.
- Check 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. Engine control module is not connected by this action.
- Check wiring for open circuit between test box and 5-pin connector using wiring diagram.
- Terminal 5 + socket 29
- Terminal 4 + socket 53
- Terminal 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.
If no wiring problem is detected:
- Replace Mass Air Flow (MAF) sensor (G70).
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again. Monitors, Trips, Drive Cycles and Readiness Codes Monitors, Trips, Drive Cycles and Readiness Codes