Mass Air Flow (MAF) Sensor, Checking
Mass Air Flow (MAF) Sensor, Checking
Special tools and equipment
- VAG1551 scan tool or VAG1552 mobile scan tool with VAG1551/3B cable
- VAG 1598/31 test box
- VAG1526 hand multimeter or VAG1715 multimeter
- VAG1594 adapter set
- Wiring diagram
Check conditions
- All fuses must be OK.
- Coolant temperature must be at least 80 °C, display group 04, display zone 3.
- 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 VAG1551 scan tool (VAG1552). Start engine and select "Address word" 01 of engine control module. When doing this the engine must be running at idling speed. (Connecting scan tool and selecting engine control module). Refer to "VAG1551 Scan Tool Tools and Equipment
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
Indicated on display:
Read measured value block HELP
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 to 4 = Display zones)
Read measured value block 2 ->
1 2 3 4
- Check the air mass drawn in display zone 4
Specification: 2.0 to 4.5 g/s
If the specification is obtained but there is a malfunction regarding Mass Air Flow (MAF) sensor registered in the DTC memory:
- Check the voltage supply for the Mass Air Flow (MAF) sensor.
If the specification is not obtained:
- Check signal and Ground (GND) wires for the Mass Air Flow (MAF) sensor.
If the specification is obtained:
- Press the -> key.
- Press keys 0 and 6 for the "End output" function and confirm input with the Q key.
- Switch ignition off.
Checking voltage supply for Mass Air Flow (MAF) sensor
- Pull 5 pin connector -1- off Mass Air Flow (MAF) sensor -2-.
- Connect multimeter to measure voltage on connector contact 2 and engine Ground (GND).
- Start engine and run at idling speed.
Specification: 11 to 15 V
If no voltage is present:
- Switch ignition off.
- Check wiring from contact 2 to fuel pump relay (J17) according to wiring diagram.
If the voltage supply and wiring is OK:
- Switch ignition on.
- Connect multimeter to measure voltage on connector contact 4 and engine Ground (GND):
Specification: 4.5 to 5.5 V
If no voltage is present:
- Switch ignition off.
- Check signal and Ground (GND) wires.
Testing signal and Ground (GND) wires for Mass Air Flow (MAF) sensor
- Connect VAG1598/31 test box to control module wiring harness. The engine control module remains disconnected.
- 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 Ohm
- Additionally check wires for short to one another.
- Additionally check wiring for short to battery positive or Ground (GND).
If no wiring fault is detected:
- Replace Mass Air Flow (MAF) sensor -G70-, item 2, Service and Repair
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory,Checking and Erasing DTC Memory. Refer to "Displaying and Reading Trouble Codes/With Manufacture Scan Tool/Check DTC Memory (Function 02)" Testing and Inspection
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again: Refer to "Monitors, Trips and/or Drive Cycle/ Reading Readiness Code" Testing and Inspection
Engine code AWW, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code." Testing and Inspection
Engine code AWP, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code." Testing and Inspection