A8 Sedan V8-3.7L (AEW) (1997)
Leak Detection Pump: Testing and Inspection
Leak Detection Pump (LDP) -V144-, Checking
Electrical check
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Disconnect harness connector for Leak Detection Pump (LDP) -V144-.
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Connect multimeter US1119 (Fluke 83 or equivalent) between terminals -1- and -3- of LDP and check resistance.
Specified value: 640 - 720 ohms
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Connect multimeter US1119 (Fluke 83 or equivalent) between terminals -2- and -3- of LDP and check resistance.
Specified value: 17.5 - 27.5 ohms
If resistance is not OK:
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Replace leak detection pump.
Voltage supply, checking
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Disconnect harness connector for LDP -V144-.
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Connect VAG1527B LED voltage tester between connector terminal -3- (B+) and engine Ground (GND).
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Start engine and let idle.
LED must light up.
If LED does not light:
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Check fuse for LDP -V144-.
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Check wiring for open circuit between terminal -3- and fuse, according to wiring diagram.
Specified value: max. 0.5 ohms
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Check fuel pump relay. See: Fuel Delivery and Air Induction/Fuel Pump/Fuel Pump Relay/Testing and Inspection