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HOMESERVICE MANUALSAUDI2004A4 BASE, 4D SEDAN, 3.0 TREPAIR AND DIAGNOSISENGINE PERFORMANCESYSTEM3.0L - IGNITION/GLOW PLUG SYSTEM, ENGINE CODES: AVK, BGNIGNITION/GLOW PLUG SYSTEMIGNITION SYSTEM, CHECKINGENGINE CONTROL MODULE (ECM) POWER SUPPLY, CHECKINGTEST SEQUENCE
2004 Audi A4 Base, 4D Sedan, 3.0 T

Test sequence

2004 Audi A4 Base, 4D Sedan, 3.0 TSECTION Test sequence
  • Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31 .
  • Switch ignition on.
    NOTE:
    • The positive voltage supply to the engine control module is provided via terminal 3 (terminal 15) and terminal 62 (terminal 30).
    • The ground connection to the engine control module is provided via terminal 1 and terminal 2.
  • Connect multimeter as follows to measure voltage:
    SOCKETS 1, 2 & 62 VOLTAGE REFERENCE (ECM POWER SUPPLY)

    Test box VAG1598/31
    Socket    		 Measure to
    1 Battery positive
    2 Battery positive
    62 Engine ground
    • Specified value: approx. battery voltage
  • Connect multimeter as follows to measure voltage:
    SOCKET 3 VOLTAGE REFERENCE (ECM POWER SUPPLY)

    Test box VAG1598/31
    Socket    		 Measure to
    3 Engine ground
  • Switch ignition on.
    • Specified value: approx. battery voltage

    If the specified values are not obtained:

  • Check wiring connections.

    See appropriate System Wiring Diagram article.

  • Connect multimeter as follows to measure voltage:
    SOCKET 121 VOLTAGE REFERENCE (ECM POWER SUPPLY)

    Test box VAG1598/31
    Socket    		 Measure to
    121(1) Engine ground
    (1) The Motronic Engine Control Module (ECM) power supply relay -J271- carries voltage on terminal 121 of engine control modules after switching off the ignition for up to 15 minutes.
  • Switch ignition on.
    • Specified value: approx. battery voltage

    If specified value is not attained:

  • Check wiring connections.

    See appropriate System Wiring Diagram article.

  • Check Motronic Engine Control Module (ECM) power supply relay -J271-. See MOTRONIC ENGINE CONTROL MODULE (ECM) POWER SUPPLY RELAY -J271-, CHECKING .
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.