Fuel Pump Circuit & Relay
- Turn ignition off. Disconnect fuel pump/sender connector. Check continuity between fuel tank unit power and ground terminals. See Fig 1
. If continuity does not exist, replace fuel pump. If continuity exists, turn ignition on. Ensure battery is fully charged. With engine off. Operate fuel pump relay. Measure voltage at pump power terminal (Pink/Black wire) of pump/sender connector. If battery voltage exists, go to next step. If voltage does not exist, go to step 3).
- Measure resistance of pump ground wire (Black wire) to chassis ground. See Fig 1
. If resistance is less than one ohm, go to next step. If resistance is not less than one ohm, repair open in Black wire between fuel pump and ground.
- Remove fuel pump relay (located in power distribution box on right inner fender). Turn ignition on. Ensure battery voltage exists on Red and Light Blue/Orange wires. If battery voltage does not exist on Red wire, check Powertrain Control Module (PCM) power relay. If battery voltage does not exist on Light Blue/Orange wire, check 20-amp FUEL PUMP fuse.
- Remove fuel pump relay. Connect 12 volts to relay terminal No. 85 and ground relay terminal No. 86. Check for continuity between relay terminals No. 30 and 87. See Figure
. If continuity is present, relay is okay. If continuity is not present, replace relay.
- Connect 12 volts to relay connector terminal No. 5 (Dark Green/Yellow wire). Fuel pump should operate. If pump does not operate, ensure Inertia Fuel Shut-Off (IFS) switch is set. IFS switch is located under dash to the right of transmission tunnel. Disconnect IFS switch connector. Check continuity between IFS switch terminals. If continuity does not exists, replace IFS switch.
Courtesy of MAZDA MOTORS CORP.