Air Flow Meter/Sensor: Testing and Inspection
Special Tools, Testers And Auxiliary Items- VAG 1551/1552 Scan Tool With VAG 1551/3 Adapter Cable
- VAG 1598/18 Test Box
- Multimeter (Fluke 83 Or Equivalent)
- Connector Test Kit VW 1594
- Wiring Diagram
Test Conditions
- Electrical consumers switched off (Radiator coolant fan must not run during the check.)
- A/C switched off
Test sequence
- Engine running at idle
- Connect VAG 1551/1552 scan tool and select "Engine Electronics" address word 01.
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 HELP
Input display group number XXX
- Press buttons -0- -1- and -5- for display group number 015 and press -Q- button to confirm input.
Indicated on display (1-4 Display fields)
Read Measuring Value Block 15-->
1 2 3 4
- Check the load registration specifications 1 (display fields 2 and 3):
- Press -C- button.
Display Group 015: Load Registration 1
- Press buttons -0- -1- and -6- for display group number 016 and press -Q- button to confirm input.
Indicated On Display (1-4 Display Fields)
Read Measuring Value Block 16-->
1 2 3 4
- Checking Load Registration Specifications 2 (display Field 3):
Evaluating Display Group 016: Display Field 3
Checking Voltage Supply
- Disconnect 4-pin connector from Mass Air Flow sensor.
- Connect multimeter with test leads from VW 1594 to measure voltage at terminals 1 and 3.
Specification: 9.0-14.5 volts
If no voltage is present:
- Switch ignition off.
- Check wiring according to wiring diagram.
Checking wiring
- Switch ignition off.
- Connect VAG 1598/18 test box to ECM wiring harness.
- Check wiring between test box and 4-pin connector for open circuit according to wiring diagram.
- Terminal 2 and test box socket 16.
- Terminal 4 and test box socket 17.
Resistance: maximum 1.5 ohms.
- Additionally, check 4-pin connector terminals for short circuit to one another.
Terminal 4 and test box socket 16
Specification: Infinite Ohms
- Set multimeter to voltage measurement range.
- Check 4-pin connector terminals for short circuit to battery positive (B+) according to wiring diagram.
- Terminal 2 and vehicle Ground.
- Terminal 4 and vehicle Ground.
Specification: 0 volts
If no wiring malfunction is detected:
- Replace Mass Air Flow sensor -G70-.
- Read the readiness code. If DTC memory has been erased, repair must be verified via appropriate display group: Readiness code, creating.