S4 V8-4.2L (BHF) (2004)
Checking activation of Fuel Pump (FP) relay
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Remove cable bridge
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Remove Fuel Pump (FP) relay.
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Connect test box to wiring harness of Engine Control Module (ECM), ECM is not connected. See: Computers and Control Systems/Testing and
Inspection/Reading and Clearing Diagnostic Trouble Codes/Scan Tool Connecting/Test Box, Connecting For Wiring and Component Test
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Check the following wire connection for open circuit according to wiring diagram.
Central electronics in driver-side
Test box Socket
footwell, left, position 4
Terminal
16
65
Specified value: Wire resistance max 1.5 Ohms
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Check the wire for short circuit to B+ and Ground (GND).
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Specified value:Infinite Ohms (no continuity)
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If necessary, repair wire connection.
If no malfunctions are detected:
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Replace Fuel Pump (FP) Relay -J17-. or
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Replace Engine Control Module (ECM).
Check voltage supply for Fuel Pump (FP) and components
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Remove fuses S228, S232, and S234 (positions 28, 32, and 34) from fuse holder.
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Connect multimeter for voltage measurement to Ground (GND) and to one terminal of the following fuses in the fuse holder.
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Operate starter briefly.
Circlip
Specified value at one of the terminals
S228
approx. battery voltage
S232
approx. battery voltage
S234
approx. battery voltage
If specified values are not obtained:
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Repeat test at another terminal of fuse socket.
If specified values are not obtained again: