1994 Audi S4FACTORY OEM SERVICE PROCEDURE

Power Supply Checking

/3A) using adapter lead (VW 1348/3-2) and adapter cables from (VW 1594) between fuse No. 17, terminal No. 2 and battery positive (+) terminal. Vehicles with A/C, connect clip to remote starter aid connection in engine compartment. NOTE: In noisy surroundings, second mechanic may be required to listen for pump operating noises under vehicle near fuel tank. Operate remote control. Fuel pump must operate audibly. If fuel pump runs, check Fuel Pump (FP) relay. See FUEL PUMP RELAY in SYSTEM & COMPONENT TESTING article. If fuel pump does not run, unscrew cover for fuel level sensor and fuel pump (under luggage compartment floor covering). Pull off connector for fuel pump and fuel level sensor. See Fig 1. Fig 1: Identifying Location Of Fuel Pump/Sending Unit In Luggage Compartment [IMAGE: http://127.0.0.1:8080/images25/G00177384/] Courtesy of AUDI OF AMERICA, INC. Connect DVOM multimeter switched DC voltage range to harness connector terminals No. 1 (Green/Yellow wire) and No. 4 (Brown wire) using cables from (VAG 1594) adapter kit. See Fig 2. Fig 2: Identifying Fuel Pump/Sending Unit Harness Connector Terminal Numbers [IMAGE: http://127.0.0.1:8080/images25/G00177385/] Courtesy of AUDI OF AMERICA, INC. Operate remote control. Voltage should be approximately battery voltage (12 volts/good battery). If specified value is not obtained, find a repair open or short to ground in wiring. See WIRING DIAGRAMS. If specified value is obtained, remove fuel level sensor. Check wires from fuel level sensor housing to fuel pump for continuity with DVOM multimeter and adapter cables. Fix open in wiring, if necessary. See Fig 3. If no break in wiring is present, replace fuel pump. Fig 3: Identifying Fuel Pump/Sending Unit Wiring Harness To Pump [IMAGE: http://127.0.0.1:8080/images25/G00177386/] Courtesy of AUDI OF AMERICA, INC.

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.