Checking power supply

WARNING: This page is about a different car, the 2006 Audi A4, 2005 Audi A4, 2004 Audi A4, and 2003 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Disconnecting Connector On Charge Air Pressure Sensor

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Disconnect connector - arrow - on charge air pressure sensor.

Fig 2: Identifying Connector Terminals 1 And 4

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Connect multimeter and measure voltage between contacts 1 and 3 of connector.
Switch on ignition.

Specification: approx. 5 V

If reading does not match specification:

Fig 3: Connecting Test Box VAG1598/31 To Engine Control Module Wiring Harness

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Connect test box VAG1598/31 to engine control module wiring harness. Engine control module must also be connected. → 24 - MULTIPORT FUEL INJECTION (MFI)

Fig 4: Identifying Connector Terminals 1 And 4

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Check for open circuit and short to Ground/positive in following wiring:

Connector contact	Test box VAG1598/31 socket
1	108
3	98

If necessary, eliminate open circuit/short circuit.

If measured value matches specification: