Jetta L4-1.8L Turbo (AWP) (2004)
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Disconnect 5-pin connector -1- from Mass Air Flow (MAF) sensor -2-.
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Connect multimeter to terminal 2 of connector and engine Ground (GND) for voltage measurement.
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Start engine, and let run at idle.
Specified value: 11.0 to 15.0 V
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Switch ignition off.
If there is no voltage:
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Check wire connection from terminal 2 to Fuel Pump (FP) Relay -J17- according to wiring diagram.
If voltage supply and wires are OK:
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Switch ignition on.
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Connect multimeter to terminal 4 of connector and engine Ground (GND) for voltage measurement:
Specified value: 4.5 to 5.5 V
If there is no voltage:
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Switch ignition off.
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Check signal and ground wires.
Checking signal and Ground wires of Mass Air Flow (MAF) Sensor
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Connect test box to control module wiring harness, connect test box for wiring test. Engine Control Module (ECM) is not connected. See:
Powertrain Management/Computers and Control Systems/Testing and Inspection/Reading and Clearing Diagnostic Trouble Codes/Scan Tool
Connecting/With Generic Scan Tool/Test Box, Connecting For Wiring Test
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Check wires between test box and 5-pin connector for open circuit according to wiring diagram.
Terminal 5 + socket 29
Terminal 4 + socket 53
Terminal 3 + socket 27
Wire resistance: max: 1.5 Ohms
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Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: Infinite Ohms
If no DTCs are found in wires:
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Replace Mass Air Flow (MAF) Sensor -G70-, item 2
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Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. See: Powertrain Management/Computers
and Control Systems/Testing and Inspection/Scan Tool Testing and Procedures/With Generic Scan Tool/Diagnostic Mode 4: Reset/Erase
Diagnostic Data