Mass Air Flow (MAF) Sensor, Checking
Mass Air Flow Sensor, Checking
Special tools and equipment
- VAG 1551/1552 Scan Tool using VAG 1551/3 adapter cable
- VAG 1598/18 Test Box
- Fluke 83 multimeter (or equivalent)
- VW 1594 Adapter kit
- Wiring diagram
Requirements
- All electrical consumers switched off (radiator fan must not run during the check)
- A/C switched off
Test sequence
- Connect VAG 1551 (VAG 1552) Scan Tool. Selectable Functions When Using VAG1551/1552 or VAS5051
- With engine idling, press buttons -0- and -1- to select "Engine electronics" address word 01.
Display will appear as shown
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to select "Read measuring value block".
- Press -C- button.
- Press buttons -0- -1- and -6- to select "Display group number 16".
- Press -Q- button to enter selection.
Display will appear as shown
Read measuring value block HELP
Input display group number XXX
- Press buttons -0-, -1- and -5- to select "Display group number 15".
- Press -Q- button to enter selection.
Display will appear as shown (1 to 4 = Display fields)
Read measuring value block 15 ->
1 2 3 4
- Check load registration specification 1 (Display fields 2 and 3).
- Press -Q- button to enter selection.
Display will appear as shown (1 to 4 = Display fields)
Read measuring value block 16 ->
1 2 3 4
- Check load specification 2 (Display field 3):
Display Group 16:
Evaluating display group 16
Voltage supply, checking
- Disconnect 4-pin Mass Air Flow sensor harness connector (arrow).
- Switch Fluke 83 multimeter to 20 Volt DC range.
- Connect multimeter between harness connector terminals 1 + 3 using jumper wires from VW 1594 adapter kit.
- specification: 9.0 to 14.5 Volts
If NO Voltage present:
- Switch ignition off.
- Check wiring according to wiring diagram.
Wiring, checking
- Switch ignition off.
- Connect VAG 1598/18 Test Box to ECM wiring harness.
- Check for open circuit between Test Box and 4-pin harness connector using wiring diagram, connecting as follows:
terminal 2 + socket 16
terminal 4 + socket 17
wire resistance: 1.5 Ohms maximum
- Check 4-pin connector wires for shorting to one another.
terminal 4 + socket 16
- specification: infinity Ohms
- Switch Fluke 83 multimeter to 20 Volt DC range
- Check 4-pin harness connector wiring for short to B+ using wiring diagram, connecting as follows:
terminal 2 + vehicle Ground
terminal 4 + vehicle Ground
- specification: 0 Volts
If wiring OK:
- Replace Mass Air Flow sensor -G70-
- Read-out Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If DTC memory was erased, create Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes