Fuel Pump Control Circuit

2AZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: Fuel Pump Control Circuit

Fuel Pump Control Circuit

DESCRIPTION

When the engine is cranked, the starter relay drive signal output from the STAR terminal of the ECM is input into the STA terminal of the ECM, and NE signal generated by the crankshaft position sensor is also input into the NE+ terminal. Thus, the ECM interprets that the engine is cranked, and turns the transistor Tr1 in the ECM internal circuit ON. The current flows to the C/OPN (Circuit Opening) relay by turning the Tr1 ON. Then, the fuel pump operates.
While the NE signal is input into the ECM, when the engine is running, the ECM turns the Tr1 on continuously.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE C/OPN RELAY)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch to the ON position and turn the tester on.
(c) Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump / Speed.
(d) Check whether the fuel pump operation sound occurs when performing the Active Test on the tester.
OK:
Fuel pump operating sound occurs.
NG -- CHECK ECM POWER SOURCE CIRCUIT
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
2. CHECK ECM POWER SOURCE CIRCUIT
NG -- REPAIR OR REPLACE ECM POWER SOURCE CIRCUIT
OK -- Continue to next step.
3. INSPECT C/OPN RELAY





(a) Remove the C/OPN relay from the engine room junction block.
(b) Measure the resistance of the C/OPN relay.
Standard resistance:





(c) Reinstall the C/OPN relay.
NG -- REPLACE C/OPN RELAY
OK -- Continue to next step.
4. INSPECT ECM (FC VOLTAGE)





(a) Disconnect the ECM connectors.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(c) Reconnect the ECM connectors.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BATTERY)
OK -- Continue to next step.
5. INSPECT FUEL PUMP
NG -- REPLACE FUEL PUMP
OK -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - FUEL PUMP - BODY GROUND)





(a) Check the harness and the connectors between the C/OPN relay and the fuel pump.
(1) Remove the C/OPN relay from the engine room junction block.
(2) Disconnect the fuel pump connector.
(3) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):





Standard resistance (Check for short):





(b) Check the harness and the connectors between the fuel pump and body ground.
(1) Disconnect the fuel pump connector.
(2) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):





(c) Reconnect the fuel pump connector.
(d) Reinstall the C/OPN relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM