HB. Checking The Fuel Pump

HB. Checking the Fuel Pump (FP)

HB1

Checking The Power Supply At The Central Electrical Module
- Ignition off.




- Remove fuse 1 (or 31).
Check that the fuse is intact.




Connect a voltmeter between the lower terminal on the fuse box (1 or 31) and GND.
The voltmeter should read battery voltage.

If the reading is incorrect
The fault lies before the fuse.
- Check the wiring between the fuse 1 (or 31) and the battery.

If the reading is OK
- Check the power supply to the FP HB2.

HB2

Checking The Power Supply To The Fuel Pump (FP)




- Remove fuse 11 and check that it is intact.




Connect a voltmeter between the upper terminal of fuse 11 and GND.
- Operate the starter motor.
The voltmeter should read 9.5-11 V.

If this value is OK
- Check the FP resistance HB5.

If the reading is 0 V.
- Check the voltage to the relay board HB3.

HB3




Checking the voltage to the relay board
- Pull out the central relay module. Ignition on.
Connect a voltmeter between terminals 3 and 4 on the back of the relay board.
The voltmeter should read battery voltage.

If this value is OK
^ check the control signal HB4.

If the reading is incorrect
^ check the wiring between terminal 3 on the relay board and fuse 1, and the wiring between terminals 3 and 4 on the relay board and #4 and #21 on the MFI control module for breaks in accordance with NA2. NA. Checking the Wiring

HB4




Checking the control signal
- Ignition on.
Connect a voltmeter between terminals 3 and 2 on the relay board.
- Operate the starter motor.
The voltmeter should read battery voltage.

If this value is OK
^ try using a new relay.

If the reading is incorrect
^ check the wiring between terminal 2 on the relay board and #20 on the MFI control module for breaks in accordance with NA2. NA. Checking the Wiring
^ If the fault remains: Continue with connecting the test box HB6.

HB5




Checking the fuel pump (FP) resistance
- Ignition off.
- Take apart the HO2S 2-pole connector.
- Disconnect the interior lighting (760/960 fuse 26,740/940 fuse 5).
Connect an ohmmeter between the upper terminal on fuse 11 and GND (760/960 fuse 30 right terminal).
The ohmmeter should read 1-2 ohms.

If this value is OK
^ the readings indicate that there is no fault In the FP's electrical circuit. The FP has a mechanical fault. Try using a new FP.

- Reconnect the HO2S 2-pole connector.
- Reconnect Interior lighting. Fuse 5 (740/940), fuse 26 (760/960).

HB6




Connecting the test box
Connect the test box and check the connections to GND in accordance with P1-P2. P. Test Box, Signal Description
^ Continue with Checking the power supply (30 supply) HB7.

HB7




Checking the power supply (30 supply)
- Connect the control module to the test box.
- Install fuse 1 (or 31).
- Ignition off.
Connect the voltmeter between #4 and #5 (GND).
The voltmeter should read battery voltage.

If this value is 0K
^ check the voltage from ignition switch (15 supply) HB8.

If the reading is incorrect
^ check the wiring between #4 and fuse 1 (or 31) for breaks in accordance with NA2. NA. Checking the Wiring

HB8




Checking the voltage from the ignition switch (15V supply)
- Ignition on.
Connect the voltmeter between #35 and #5 (GND). The voltmeter should read battery voltage. Check that there Is a voltage reading when the starter motor is operating as well.

If this value is OK
^ check the engine speed signal from DI HB9.

If the reading deviates
^ check the wiring between #35 and the Ignition switch via fuse 1 (or 31) for breaks in accordance with NA2. NA. Checking the Wiring

HB9




Checking the engine speed signal from DI EZ 116 K
Connect a voltmeter between #1 and #5 (GND).
- Operate the starter motor.
The voltmeter should read 6-9 volt.

If the value is OK
^ check the injector circuit HB10.

If the reading is incorrect
^ check the wiring between MFI and DI for breaks In accordance with NA2. NA. Checking the Wiring

HB10




Checking the Injector circuit
- Ignition on.
Connect a voltmeter between #18 and #17 (power GND).
The voltmeter should read battery voltage.

If the reading is incorrect
^ check the wiring and connections between MFI #18 and terminal 3 on the suppressor relay for breaks or grounding in accordance with NA2 and NA3. NA. Checking the Wiring