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:

NOTE: Information marked with an asterisk (*) applies to except KG, KS, KE, KR, KU, KN, KH, KY, KZ, FO, KQ, KK, KM models.

1.Turn the ignition switch OFF.

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

 


3.Turn the ignition switch ON (II).

4.Measure voltage between PGM-FI main relay 2 4P connector terminal No. 4 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 PGM-FI main relay 2 4P connector terminal No. 1 and body ground.

 

Is there battery voltage?


YES - Go to 6.


NO - Repair open in the wire between the under-dash fuse/ relay box and  PGM-FI main relay 2.n


6.Turn the ignition switch OFF.

7.Disconnect the negative cable from the battery.

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

9.Check for continuity between PGM-FI main relay 2 4P connector terminal No. 3 and ECM/PCM connector terminal E1 (E10)*.

 

Is there continuity?


YES - Go to 10.


NO - Repair open in the wire between the  PGM-FI main relay 2 and the  ECM/ PCM (E1, E10*).n

10.Reinstall the PGM-FI main relay 2.

11.Reconnect the negative cable to the battery.

12.Turn the ignition switch ON (II).

13.Measure voltage between ECM/PCM connector terminal E1 (E10)* and body ground.

 

Is there battery voltage?


YES - Go to 14.


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


14.Turn the ignition switch OFF.

15.Disconnect the negative cable from the battery.

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

17.Reconnect the negative cable to the battery.

18.Turn the ignition switch ON (II), and measure voltage between ECM/PCM connector terminal E1 (E10)* and body ground within the first 2 seconds after the ignition switch was turned ON (II).

 

Is there battery voltage?


YES - Substitute a known-good ECM/PCM and recheck. If symptom/indication goes away, replace the original  ECM/ PCM.n


NO - Go to 19.

19.Turn the ignition switch OFF.

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

21.Remove the access panel from the floor.

22.Measure voltage between 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 28.


NO - Go to 23.


23.Turn the ignition switch OFF.

24.Remove the PGM-FI main relay 2.

25.Connect PGM-FI main relay 2 4P connector terminals No. 1 and No. 2 with a jumper wire.

 


26.Turn the ignition switch ON (II).

27.Measure voltage between 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


28.Turn the ignition switch OFF.

29.Check for continuity between 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