Fuel Pump Inspection (B2300, B3000, B4000 & Tribute)

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2003 Mazda Tribute, 2003 Mazda Protege5, 2003 Mazda Protege, 2003 Mazda MX-5 Miata, and 2003 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.

Check Fuel Pump For Operation

Verify battery is fully charged. Verify fuel tank unit 4-pin harness connector is securely connected. Turn ignition on, engine off. Connect scan tool to DLC. Select DIAGNOSTIC DATA LINK. Select PCM. Select ACTIVE COMMAND MODE. Select OUTPUT TEST MODE and fuel pump PID. Press MODE to change to ALL ON MODE. Press START to run fuel pump and listen for fuel pump operation. Press STOP. If fuel pump operation was heard, go to FUEL DELIVERY SYSTEM for more trouble shooting procedures. If fuel pump operation is not heard, go to next step.

Check Fuel Pump For Continuity

Turn ignition off. Disconnect fuel tank unit 4-pin harness connector. See Fig 1 or Fig 2 . Check for continuity between fuel tank unit 4-pin connector power terminal (Pink/Black wire) and ground terminal (Black wire). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. If continuity is present, go to next step. If continuity is not present, replace fuel pump.

Fig 1: Identifying Fuel Tank Unit 4-Pin Harness Connector (B2300, B3000 & B4000)
Courtesy of MAZDA MOTORS CORP.

Fig 2: Identifying Fuel Tank Unit 4-Pin Harness Connector (Tribute)
Courtesy of MAZDA MOTORS CORP.

Check Voltage At Fuel Pump (Vehicle Harness Connected)

Turn ignition on, engine off. Select DIAGNOSTIC DATA LINK. Select PCM. Select ACTIVE COMMAND MODE. Select OUTPUT TEST MODE. On Tribute, select FUEL PUMP PID. On all models, press MODE to change to ALL ON MODE. Press START to run fuel pump. Measure voltage at fuel tank unit 4-pin connector power terminal (Pink/Black wire). Press STOP. If voltage is more than 10.5 volts, go to next step. If voltage reading is 10.5 volts or less, check fuel pump relay or Inertia Fuel Shut-off (IFS) switch.

Check Fuel Pump Ground Circuit

With fuel tank assembly 4-pin harness connector disconnected. See Fig 1 or Fig 2 . Measure resistance between fuel tank unit 4-pin connector ground terminal (Black wire) and chassis ground. If resistance is less than one ohm, ground circuit is okay. Recheck fuel pump. If resistance reading is one ohm or more, repair open circuit in Black wire between fuel tank assembly 4-pin harness connector and chassis ground.