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Home >> Audi >> 1990 >> 100 Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Fuel System >> Fuel Pressure (Cis-E III) >> Fuel Pump Relay
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Fuel Pump Relay

  1. With ignition off, remove fuel pump relay from relay panel. Connect multimeter between relay terminals No. 48 and 50. See Fig 1 . Multimeter should read 12 volts.
  2. Connect multimeter between terminals No. 46 and 50. Turn ignition on. Multimeter should read 12 volts.
  3. If multimeter does not read as specified, repair break in wiring. Connect multimeter between terminals No. 46 and 47. Momentarily engage starter. Multimeter should read 7 volts.
    NOTE: ICU terminal identifications are located on connector.
  4. If multimeter does not read 7 volts, partially remove ICU and disconnect harness connector. Using a multimeter, check continuity between ICU and fuel pump relay.
  5. Connect ICU connector terminal No. 3 to relay terminal No. 49. Connect ICU connector terminal No. 14 and relay terminal No. 47. Multimeter reading should be .2 ohm.
  6. If reading is not as specified, repair break in wiring. If reading is as specified, replace knock sensor.
Fig 1: Checking Fuel Pump Relay Circuit (CIS-E III)
G94349Courtesy of AUDI OF AMERICA, INC.
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