Fuel Pump

SYSTEM DESCRIPTION




Fuel Pump ON-OFF Control
The ECM activates the fuel pump for several seconds after the ignition switch is turned ON to improve engine start-up. If the ECM receives a 1° signal from the crankshaft position sensor (POS), it knows that the engine is rotating, and causes the pump to activate. If the 1° signal is not received when the ignition switch is ON, the engine stalls. The ECM stops pump operation and prevents the battery from 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. Operates for 1 second
Engine running and cranking Operates
Except as shown above Stops

CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Specification data are reference values.




ECM TERMINALS AND REFERENCE VALUE
Remarks: Specification data are reference values, and are measured between each terminal and (25) (ECCS ground) with a voltmeter.

EC-F/PUMP-01 Fuel Pump Control:

WIRING DIAGRAM




DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION
Fuel Pump Relay
Check continuity between terminals




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 20°C (68°F) If NG, replace fuel pump.

If NG, replace fuel pump.