A8 Quattro Sedan V8-4.2L (AUX) (2001)
Testing activation of fuel pump relay
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Switch ignition off.
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Connect VAG1598/31 test box to wiring harness for engine control unit. Do not connect to engine control module itself. Refer to "Scan Tool
Testing/Scan Tool Connecting and Initial Checks/Connecting VAG1598/31 Test Box" See: Powertrain Management/Computers and Control
Systems/Testing and Inspection
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Connect sockets 65 and 2 of test box to each other using test leads from VAG1594 connector test kit.
Specification: The fuel pump relay (relay position 4) should be activated.
If the relay is now activated but not during the output Diagnostic Test Mode (DTM):
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Replace Engine Control Module (ECM).
If the relay does not activate:
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Disconnect fuel pump relay from relay panel (relay position 4).
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Connect hand-held multimeter (voltage measurement range) between Ground (GND) and terminal 19 on relay panel.
Specification: approx. battery voltage
If the specification is not obtained:
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Check wiring.
If the specification is obtained: