A4 Cabriolet L4-1.8L Turbo (AMB) (2005)
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In diagnostic function "33 - OBD", select "Mode 1: Checking measured values."
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Select the desired measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor".
Specified value: 2.0 to 4.5 g/s
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End diagnosis and switch ignition off.
If the specified value is not reached:
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Check intake air system for leaks (false air). See: Testing and Inspection/Component Tests and General Diagnostics/Intake System, Checking For
Leaks (False/Unmetered Air)
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Check voltage supply and wire connections.
If the specified value is exceeded:
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Eliminate engine load via additional equipment (A/C system/power-assisted steering/alternator).
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Check voltage supply and wire connections.
Checking voltage supply
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Disconnect harness connector -arrow- at Mass Air Flow (MAF) sensor.
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Connect multimeter for voltage measurement as follows.
Harness connector Terminal
Measure to
2
Engine Ground (GND)
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Operate starter briefly.
Specified value: approx. battery voltage
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Switch ignition off.
If specified value is not obtained:
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Check wire connection from harness connector terminal 2 to Fuel Pump (FP) Relay -J17- via fuse for open circuit according to wiring diagram.
Specified value: Wire resistance max 1.5 Ohms
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necessary, repair wire connection.