S4 Quattro Sedan V6-2.7L Turbo (APB) (2000)
Mass Air Flow Sensor: Testing and Inspection
Mass Air Flow (MAF) Sensor, Checking - Hitachi
Voltage Supply For Mass Air Flow (MAF) Sensor, Checking (Hitachi MAF Sensor)
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Disconnect connector from Mass Air Flow (MAF) sensor.
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Connect multimeter to terminal 2 of connector and engine Ground (GND) for voltage measurement.
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Operate starter briefly.
Specification: approx. battery voltage
NOTE: Voltage is supplied to Mass Air Flow (MAF) sensor from Fuel Pump (FP) relay.
If there is no battery voltage.
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Check wire connection from terminal 2 of connector to Fuel Pump (FP) relay via fuse for open circuit and short circuit to Ground (GND), repair if
necessary.
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Connect multimeter to terminal 2 and terminal 3 of connector for voltage measurement.
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Operate starter briefly.
Specification: approx. battery voltage
NOTE: Ground (GND) from the ECM is present at terminal 3 of connector.
If specified value is not obtained, check wire connections.
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Connect multimeter to terminal 3 and terminal 1 of connector for voltage measurement.
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Switch ignition on.
Specification: approx. 5 volts.
If specified value is not obtained, check wire connections .
Wire Connections For Mass Air Flow (MAF) Sensor, Checking (Hitachi MAF Sensor)
NOTE: Signal wire is also checked during wire test.
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Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to "Scan Tool Testing/Wiring And Component Check With
VAG1598/31 Test Box" See: Computers and Control Systems/Testing and Inspection