With Manufacturer's Scan Tool
Mass Air Flow (MAF) Sensor, Checking
NOTE: Only gold-plated terminals can be used to repair terminals in the connector for the Mass Air Flow (MAF) sensor.
Special tools, test equipment and auxiliary items
- VAG 1551 scan tool or VAG 1552 mobile scan tool with VAG 1551/3B cable
- VAG 1598/31 test box
- VAG 1526 hand multimeter or VAG 1715 multimeter
- VAG 1594 adapter set
- Electrical Wiring Diagram
Test conditions
- All fuses must be OK
- Battery voltage must be at least 11.5 V
- Fuel pump relay must be OK
- All electrical accessories, e.g. lights and rear window defroster must be switched off
- If the vehicle is equipped with air conditioning, it must be turned off
- On vehicles with automatic transmission: selector lever in "P" or "N" position
- Engine Coolant Temperature (ECT) must be at least 80 °C, see display group 04, display zone 3
Test sequence
- Connect VAG 1551 scan tool ((VAG 1552). Start engine and select "Address word" 01 of Motronic Engine Control Module (ECM) -J220-. Engine must be running at idle speed. (Connecting scan tool and selecting Motronic Engine Control Module (ECM) -J220-). [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 to 4 = Display zones)
Read measuring value block 2 ->
1 2 3 4
- Check Mass Air Flow drawn in in display zone 4:
Specification: 2.0 to 4.5 g/s
- If value is as specified but DTC memory has recorded a DTC relating to Mass Air Flow (MAF) sensor, test power supply to Mass Air Flow (MAF) sensor.
If the specification is not obtained:
- Check signal and Ground (GND) wires for Mass Air Flow (MAF) sensor.
If the specification is obtained:
- Press -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with -Q- button.
- Switch off ignition.
Testing power supply to Mass Air Flow (MAF) sensor -G70-
- Disconnect 5-pin connector -1- from Mass Air Flow (MAF) sensor -G70- arrow.
- Connect multimeter to measure voltage on connector terminal 2 and engine Ground (GND).
- Start engine and run at idle speed.
Specification: 11.0 to 15.0 V
If no voltage is present:
- Switch off ignition.
- Check wire between 5-pin connector terminal 2 and Fuel Pump (FP) Relay -J17- for open circuit using Electrical Wiring Diagram.
Wire resistance: max. 1.5 Ohms
If the voltage supply and wiring is OK:
- Connect multimeter to measure voltage on connector terminal 4 and engine Ground (GND).
- Switch on ignition.
Specification: 4.5 to 5.5 V
If no voltage is present:
- Switch off ignition.
- Check signal and Ground (GND) wires.
Testing signal and Ground (GND) wires for Mass Air Flow (MAF) sensor -G70-
- Remove inner plenum chamber cover, left
- Connect VAG 1598/31 test box to control module wiring harness. Motronic Engine Control Module (ECM) -J220- is not connected by this action.
- Check wiring for open circuit between test box and 5-pin connector using Electrical 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 (GND).
NOTE: Socket 1 in Mass Air Flow (MAF) sensor and connector is not occupied.
If no wiring malfunction is found:
- 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. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes