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 glove box, then remove the PGM-FI main relay 2 (A).

 

3.Turn the ignition switch ON (II).

4.Measure voltage between the PGM-FI main relay 2 5P connector terminal No. 5 and body ground.

 

Is there battery voltage?


YES - Go to 5.


NO - Repair open in the wire between the PGM-FI main relay 1 and the PGM-FI main relay 2.n

5.Measure voltage between the PGM-FI main relay 2 5P connector terminal No. 1 and body ground.

 

Is there battery voltage?


YES - Go to 11.


NO -

  • KE, KG, KS models: go to 6.
  • Except KE, KG, KS models: repair open in the wire between the under-dash fuse/relay box and PGM-FI main relay 2.

6.KE, KG, KS models:
Turn the ignition switch OFF.

7.KE, KG, KS models:
Disconnect the inertia switch 3P connector.

8.KE, KG, KS models:
Connect the inertia switch 3P connector terminals No. 1 and No. 3 with a jumper wire.

 

9.KE, KG, KS models:
Turn the ignition switch ON (II).

10.KE, KG, KS models:
Measure voltage between the PGM-FI main relay 2 5P connector terminal No. 1 and body ground.

 

Is there battery voltage?


YES - Replace the  inertia switch.n


NO -

  • Repair open in the wire between the under-dash fuse/relay box and PGM-FI main relay 2.n
  • Repair open in wires between inertia switch and under-dash fuse/relay box.n

11.Turn the ignition switch OFF.

12.Jump the SCS line with the HDS.

13.Disconnect ECM/PCM connector E (31P).

14.Check for continuity between the PGM-FI main relay 2 5P connector terminal No. 3 and ECM/PCM connector terminal E17.

 

Is there continuity?


YES - Go to 15.


NO - Repair open in the wire between the PGM-FI main relay 2 and the ECM/PCM (E17).n


15.Reinstall the PGM-FI main relay 2.

16.Turn the ignition switch ON (II).

17.Measure voltage between ECM/PCM connector terminal E17 and body ground.

 

Is there battery voltage?


YES - Go to 18.


NO - Replace the  PGM-FI main relay 2.n


18.Turn the ignition switch OFF.

19.Reconnect ECM/PCM connector E (31P).

20.Turn the ignition switch ON (II), and measure voltage between ECM/PCM connector terminal E17 and body ground within the first 2 seconds after the ignition switch was turned ON (II).

 

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 sympton/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.n


NO - Go to 21.

21.Turn the ignition switch OFF.

22.Fold the rear seats forward, and pull back the carpet to expose the access panel.

23.Remove the access panel from the floor.

24.Measure voltage between the fuel pump 5P connector terminal No. 5 and body ground within the first 2 seconds after the ignition switch was turned ON (II).

 

Is there battery voltage?


YES - Go to 30.


NO - Go to 25.

25.Turn the ignition switch OFF.

26.Remove the PGM-FI main relay 2.

27.Connect the PGM-FI main relay 2 5P connector terminals No. 1 and No. 2 with a jumper wire.

 

28.Turn the ignition switch ON (II).

29.Measure voltage between the fuel pump 5P connector terminal No. 5 and body ground within the first 2 seconds after the ignition switch was turned ON (II).

 

Is there battery voltage?


YES - Replace the  PGM-FI main relay 2.n


NO - Repair open in the wire between the PGM-FI main relay 2 and the fuel pump 5P connector.n

30.Turn the ignition switch OFF.

31.Check for continuity between the fuel pump 5P 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 pump 5P connector and G551.n