Nissan MICRA K12 Fuel Pump Circuit

The ECM controls the fuel pump relay which controls the pump.

 

Diagnostic procedure

 

Function check:

Switch on ignition.

Hold the hose that feeds the fuel between 2 fingers and press

You should feel the pressure pulse of the fuel in the hose foe 1 sec. after ignition on.

If not so then go to the next step.

 

Power supply circuit of the fuel pump relay

Switch off ignition

Disconnect the harness connector to the ECM

Switch on ignition.

Between ECM terminal 113 and ground check voltage (battery).

Good: go to 5                                 NG: go to the next step.

 

Power supply circuit 1 of the fuel pump

Switch off ignition.

Disconnect the harness connector E17 IPDM E/R.

Switch off ignition.

Between IPDM E/R terminal 69 and ground check the voltage (battery).

Good: proceed to the next step.    NG: proceed to perform Intermittent Incident.

 

Find the malfunction, check:

IPDM E/R connector 17

For open / short in harness between IPDM E/R and ECM.

Repair > Harness / Connectors.

 

For open & short in fuel pump power supply circuit and ground circuit

Switch off ignition.

Disconnect the harness connector to the fuel pump and the fuel level sensor unit.

Check for harness continuity between

IPDM E/R connector 13 terminal 20 and fuel level sensor unit and fuel pump terminal 1.

Fuel level sensor unit and fuel pump terminal 3 and body ground.

Continuity should be present.

For short to ground / power in harness.

Good: skip the next step                NG: proceed to the next step.

 

Find the malfunction, check:

Harness connectors M1, E101

                                 B1, M10

For open/short in harness between fuel level sensor unit & fuel pump & IPDM E/R

                                                       fuel level sensor unit & fuel pump & body ground

Repair > open / short to ground / power in harness / connectors.

 

For open & short in relay output signal circuit of fuel pump

Disconnect the harness connector to the ECM.

Between ECM terminal 113 and IPDM E/R connector terminal 69, harness continuity.

There should be continuity.

Harness for short to ground and power.

Good: proceed to the next step.     NG: repair open/short between ECM & IPDM E/R.

 

Inspection of the component: Fuel Pump

Disconnect the fuel level sensor unit and the harness connector to the fuel pump.

Check resistance between fuel level sensor unit and the fuel pump terminals 1& 3.

Resistance should be 1.0W at 25°C or 77°F

Good: perform Intermittent Incident.        NG: replace the fuel pump.

 

Intermittent Incident   

Good: replace IPDM E/R               NG: repair / replace harness / connector.