A8L Quattro Sedan V8-4.2L (AKB) (2002)
Fuel Pump Relay: Testing and Inspection
Fuel Pump (FP) Relay -J17 and Relay Activation, Checking
The fuel pump and some of the injection system components are powered via the fuel pump relay -J17
The Fuel Pump (FP) relay -J17 will only be activated if the engine is turning over. That means, the relay is only grounded (via the engine control module
) when the engine control module is receiving engine speed impulses.
Test conditions
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Battery voltage OK
Functional test of fuel pump relay
NOTE: The fuel pump relay is located in the electronics box in the front passenger's footwell (central electrics unit, relay position 4).
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Connect vehicle diagnostic, testing and information system VAS5051 or VAG1551 scan tool and select engine electronics control module by
entering address word "01". When doing this the ignition must be switched on. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial
Checks/Connecting VAS5051 or VAG1551" See: Powertrain Management/Computers and Control Systems/Testing and Inspection
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Start output Diagnostic Test Mode (DTM). The fuel pump must be running. Refer to "Scan Tool Testing/Output Diagnostic Test Mode (DTM)
(Function 03)" See: Powertrain Management/Computers and Control Systems/Testing and Inspection
The fuel pump relay should activate and the fuel pump should run.
If the relay does not activate:
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Check activation of fuel pump relay.
If fuel pump does not run:
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Check activation of fuel pump and other components.