Fuel Pump Control Circuit

1AR-FE ENGINE CONTROL: SFI SYSTEM: Fuel Pump Control Circuit
- Fuel Pump Control Circuit

DESCRIPTION

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

While the NE signal is input into the ECM when the engine is running, the ECM turns Tr1 on continuously.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE FUEL PUMP / SPEED)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON and turn the Techstream on.

(c) Enter the following menus: Powertrain / Engine / Active Test / Control the Fuel Pump / Speed.

(d) Check whether the fuel pump operating sound occurs when performing the Active Test on the Techstream.

Result





B -- READ VALUE USING TECHSTREAM (STARTER SIGNAL)
A -- Continue to next step.

2. INSPECT RELAY (C/OPN RELAY)

(a) Inspect the C/OPN relay Testing and Inspection.

NG -- REPLACE RELAY (C/OPN RELAY)
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - ECM)

(a) Disconnect the ECM connector.

(b) Remove the C/OPN relay from the engine room relay block.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





(d) Reconnect the ECM connector.

(e) Reinstall the C/OPN relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - IGNITION SWITCH, A/F HTR RELAY)

(a) Disconnect the ignition switch connector.

(b) Remove the C/OPN relay and A/F HTR relay from the engine room relay block.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





(d) Reconnect the ignition switch connector.

(e) Reinstall the C/OPN relay and A/F HTR relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - FUEL SUCTION WITH PUMP AND GAUGE TUBE ASSEMBLY)

(a) Remove the C/OPN relay from the engine room relay block.

(b) Disconnect the fuel suction with pump and gauge tube connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





(d) Reinstall the C/OPN relay.

(e) Reconnect the fuel suction with pump and gauge tube connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (FUEL SUCTION WITH PUMP AND GAUGE TUBE ASSEMBLY - BODY GROUND)

(a) Disconnect the fuel suction with pump and gauge tube connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





(c) Reconnect the fuel suction with pump and gauge tube connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

7. INSPECT FUEL SUCTION WITH PUMP AND GAUGE TUBE ASSEMBLY

(a) Inspect the fuel suction with pump and gauge tube assembly Testing and Inspection.

NG -- REPLACE FUEL SUCTION WITH PUMP AND GAUGE TUBE ASSEMBLY Removal

OK -- REPLACE ECM Removal

8. READ VALUE USING TECHSTREAM (STARTER SIGNAL)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List/ Starter Signal.

(e) Check the result displayed on the Techstream when the ignition switch is turned to ON and the engine is started.

OK:





NG -- REPAIR OR REPLACE STARTING SYSTEM Component Tests and General Diagnostics
OK -- Continue to next step.

9. READ VALUE USING TECHSTREAM (ENGINE SPEED)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List/ Engine Speed.

(e) Read the value displayed on the Techstream while cranking.

OK:

Values are displayed continuously.

NG -- REPAIR OR REPLACE CRANKSHAFT POSITION SENSOR CIRCUIT SFI System

OK -- REPLACE ECM Removal