With Manufacturer's Scan Tool
Mass Air Flow (MAF) Sensor, Checking
NOTE: Only gold plated contacts can be used to repair Terminals in the connector for the Mass Air Flow (MAF) sensor.
Special tools and equipment
- V.A.G1551 Scan Tool (ST) or VAG1552 mobile scan tool with VAG1551/3 adapter cable
- VAG1598/22 test box
- Multimeter (Fluke 83 or equivalent)
- VW1594 adapter set
- Wiring diagram
Test requirements
- Fuse 43 OK
- Battery (B+) voltage at least 11.5 V
- Fuel pump relay OK
- Turn off all electrical consumers (e.g. lights and window defroster)
- Turn off air conditioner
- Automatic transmission selector lever in P (Park) or N (Neutral) position (if equipped)
- Min. coolant temp. 85 °C see display group 04, display field 3
Test sequence
- Connect V.A.G1551 (VAG1552) Scan Tool (ST). [1][2]Reading and Clearing Diagnostic Trouble Codes
- Turn on ignition and press buttons -0- and -1- to insert "Engine Electronics" address word 01. When doing this step, the engine must be running at idle.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08 and press -Q- button to confirm input.
Indicated on display
Read Measuring Value Block
Input display group number XXX
- Press buttons -0-, -0- and -5- to input display group number 5 (005) and press -Q- button to confirm input.
Indicated on display: (1-4 = display fields)
Read Measuring Value Blocks 5 ->
1 2 3 4
- Observe Closed Throttle Position (CTP) switch operating mode in display field 4.
Display Group 005:
If the specified value is obtained:
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06 and press -Q- button to confirm input.
- Turn off ignition.
- If value is as specified, but DTC memory has recorded a malfunction relating to Mass Air Flow (MAF) sensor, test power supply to the Mass Air Flow (MAF) sensor.
Continuation
If the specified value is not obtained:
- Check Closed Throttle Position (CTP) switch. Refer "Throttle Valve Control Module, Check" Testing and Inspection
- Press -C- button.
- Press buttons 0, 0 and 2 to input display group number 2 and press -Q- button to confirm input.
Indicated on display (1-4 = display fields)
Read Measuring Value Block 2 ->
1 2 3 4
- Check air mass drawn in in display field 4.
Display Group 2:
- If value is as specified, DTC memory has recorded a malfunction relating to Mass Air Flow (MAF) sensor, test signal and Ground (GND) wires of Mass Air Flow (MAF) sensor.
If the specified value is obtained:
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06 and press -Q- button to confirm input.
- Turn off ignition.
Evaluating display group 2, display field 4 - Air mass drawn in
Testing power supply to Mass Air Flow (MAF) sensor
- Disconnect 5-pin harness connector from Mass Air Flow (MAF) sensor -G70- with Intake Air Temperature (IAT) sensor -G42- (arrow).
- Connect multimeter to measure voltage on harness connector terminal -2- and engine Ground (GND).
- Start engine and run at idle.
Specified value: 11.0-15.0 V
If no voltage is present:
- Turn off ignition.
- Check wire between 5-pin harness connector terminal 2 and Fuel Pump (FP) relay -J17- for open circuit according to wiring diagram.
Wire resistance: max. 1.5 ohms
If the voltage supply and wiring is OK:
- Connect multimeter to measure voltage on harness connector terminal -4- and engine Ground (GND).
- Turn on ignition.
Specified value: min. 4.5 V
If no voltage is present:
- Turn off ignition.
- Check signal and Ground (GND) wires.
Testing signal and Ground (GND) wires for Mass Air Flow (MAP) sensor
- Remove wiper arms and plenum chamber cover.
- Connect VAG1598/22 test box to control module wiring harness.
- Check wiring between test box and 5-pin harness connector for open circuit according to wiring diagram.
- Terminal -5- + socket 13
- Terminal -4- + socket 11
- Terminal -3- + socket 12
- Wire resistance: max. 1.5 ohms
- Additionally, check all wires for short circuit to one another.
Specified value: Infinity ohms
- Check wiring additionally for short circuit to battery positive (B+)/Ground (GND).
If no malfunction is found in the wiring:
- Replace Mass Air Flow (MAF) sensor -G70-. Refer to item 3 Service and Repair
- Check DTC memory. If necessary, repair any malfunctions and erase DTC memory.
Reading Diagnostic Trouble Codes
Clearing Diagnostic Trouble Codes
If DTC memory has been erased or the Engine Control Module (ECM) was disconnected from permanent battery (B+) voltage, generate the readiness code again. Monitors, Trips, Drive Cycles and Readiness Codes