A8 Quattro Sedan V8-4.2L (AUX) (2001)
NOTE: The air mass meter receives its voltage supply via the fuel pump relay.
If the reading does not match the battery voltage:
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Check for open circuit or short to Ground (GND) in wiring between fuel pump relay and socket 2 on connector via fuse. Repair if necessary.
If specification is met:
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Check Ground (GND) connection from control module.
Checking Ground (GND) connection
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Connect hand-held multimeter (voltage measurement range) between sockets 2 and 3 of connector.
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Operate starter briefly. Specification: approx. battery voltage
NOTE: Socket 3 on the connector is the Ground (GND) connection from the engine control module.
If the specification is not attained:
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Check wiring.
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Connect hand-held multimeter (voltage measurement range) between sockets 3 and 4 of connector.
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Switch ignition on.
Specification: approx. 5 V
If the specification is not attained:
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Check wiring.
Checking wiring for mass air flow sensor
NOTE: The wiring test includes also testing the signal wire.