Fuel Pump: Testing and Inspection

SYSTEM DESCRIPTION
The ECM activates the fuel pump for several seconds after the ignition switch is turned on to improve engine startability. If the ECM receives a 1800 signal from the camshaft position sensor, it knows that the engine is rotating, and causes the pump to perform. If the 180° signal is not received when the ignition switch is on, the engine stalls. The ECM stops pump operation and prevents battery discharging, thereby improving safety. The ECM does not directly drive the fuel pump. It controls the ON/OFF fuel pump relay, which in turn controls the fuel pump.

Condition / Fuel pump operation
Ignition switch is turned to ON. / Operation for 5 seconds
Engine running and cranking / Operates
when engine is stopped / Stops in 1 second
Except as shown above / Stops




COMPONENT DESCRIPTION
A turbine type design fuel pump is used in the fuel tank.




CONSULT REFERENCE VALUE IN DATA MONITOR MODE




ECM TERMINALS AND REFERENCE VALUE
Specification data are reference values and are measured between each terminal and (43) (ECCS ground).







DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION
Fuel Pump Relay




Check continuity between terminals (1) and (2).

Conditions / Continuity
12V direct current supply
between terminals (1) and (2) / Yes
No current supply / No

If NG, replace relay.

Fuel Pump
1. Disconnect fuel pump harness connector.




2. Check resistance between terminals (1) and (2).

Resistance: 0.2 - 5.0 Ohms [at 25°C (77°F)]

If NG, replace fuel pump.