Fuel Pump Circuit Troubleshooting

If you suspect a problem with the fuel pump, check that the fuel pump actually runs; when it is on, you will hear some noise if you listen to the fuel fill port with the fuel fill cap removed. The fuel pump should run for 2 seconds when the ignition switch is first turned on. If the fuel pump does not make noise, check as follows:

1.Turn the ignition switch OFF.

2.Remove the under-dash fuse/relay box, then remove PGM-FI main relay 2 (FUEL PUMP) (A) from the under-dash fuse/relay box.

 

3.Reinstall the under-dash fuse/relay box.

4.Turn the ignition switch ON (II).

5.Measure voltage between PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 3 and body ground.

 

Is there battery voltage?


YES - Go to 10.


NO - Go to 6.


6.Turn the ignition switch OFF.

7.Disconnect the under-hood fuse/relay box 10P connector.

8.Turn the ignition switch ON (II).

9.Measure voltage between under-hood fuse/relay box 10P connector terminal No. 5 and body ground.

 

Is there battery voltage?


YES - Repair open in the wire between the under-hood fuse/relay box and the under-dash fuse/relay box.n


NO -

10.Measure voltage between PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 1 and body ground.

 

Is there battery voltage?


YES - Go to 16.


NO - KE, KG, TR models: Go to 11.
Except KE, KG, TR models:

  • Replace the No. 2 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.n
  • Replace the under-dash fuse/relay box.n

11.Turn the ignition switch OFF.

12.Disconnect the inertia switch 3P connector.

13.Connect inertia switch 3P connector terminals No. 1 and No. 3 with a jumper wire.

 

14.Turn the ignition switch ON (II).

15.Measure voltage between PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 1 and body ground.

 

Is there battery voltage?


YES - Replace the inertia switch.n


NO -

  • Replace the No. 2 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.n
  • Replace the under-dash fuse/relay box.n
  • Repair open in wires between inertia switch and under-dash fuse/relay box.n

16.Turn the ignition switch OFF.

17.Connect PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 4 to body ground with a jumper wire.

 

18.Jump the SCS line with the HDS.

19.Disconnect ECM/PCM connector A (44P).

20.Check for continuity between body ground and ECM/PCM connector terminal A15.

 

Is there continuity?


YES - Go to 21.


NO - Repair open in the wire between PGM-FI main relay 2 (FUEL PUMP) and the ECM/PCM (A15).n


21.Remove the under-dash fuse/relay box, then reinstall PGM-FI main relay 2 (FUEL PUMP).

22.Reinstall the under-dash fuse/relay box.

23.Connect ECM/PCM connector terminal A6 to body ground with a jumper wire.

 

24.Turn the ignition switch ON (II).

25.Measure voltage between ECM/PCM connector terminal A15 and body ground.

 

Is there battery voltage?


YES - Go to 26.


NO - Replace  PGM-FI main relay 2 (FUEL PUMP).n


26.Turn the ignition switch OFF.

27.Reconnect ECM/PCM connector A (44P).

28.Open the SCS line with the HDS.

29.Turn the ignition switch OFF.

30.Turn the ignition switch ON (II), and measure voltage between under-dash fuse/relay box 34P connector terminal No. 10 and body ground within 2 seconds.

 

Is there battery voltage?


YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM, then go to 31.


NO - If needed, replace the under-dash fuse/relay box, then go to 31.


31.Turn the ignition switch OFF.

32.Remove the rear-seat cushion.

33.Remove rear floor upper cross-member, then remove the access panel from the floor.

34.Turn the ignition switch ON (II), and measure voltage between fuel tank unit 4P connector terminal No. 2 and body ground within 2 seconds.

 

Is there battery voltage?


YES - Go to 39.


NO - Go to 35.


35.Turn the ignition switch OFF.

36.Remove PGM-FI main relay 2 (FUEL PUMP).

37.Connect PGM-FI main relay 2 (FUEL PUMP) 4P connector terminals No. 1 and No. 2 with a jumper wire.

 

38.Turn the ignition switch ON (II), and measure voltage between fuel tank unit 4P connector terminal No. 2 and body ground within 2 seconds.

 

Is there battery voltage?


YES - Replace  PGM-FI main relay 2 (FUEL PUMP).n


NO - Repair open in the wire between PGM-FI main relay 2 (FUEL PUMP) and the fuel tank unit 4P connector.n


39.Turn the ignition switch OFF.

40.Check for continuity between fuel tank unit 4P connector terminal No. 4 and body ground.

 

Is there continuity?


YES - Replace the fuel pump.n


NO - Repair open in the wire between the fuel tank unit 4P connector and G601.n