Fuel Pump Control Circuit

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

DESCRIPTION

When the engine is cranked, the ST (Starter) relay drive signal output from the ignition switch assembly*1 or certification ECU (smart key ECU assembly)*2 is input to the STA terminal of the ECM, and the NE signal generated by the crankshaft position sensor is also input to the NE+ terminal. Thus, the ECM interprets that the engine has been cranked, and turns transistor Tr1 in the ECM internal circuit on. Current flows to the C/OPN (Circuit Opening) relay by turning Tr1 on. Then, the fuel pump operates.

While the NE signal is input to the ECM with the engine running, the ECM turns Tr1 on continuously.

* *1: w/o smart key system.

* *2: w/ smart key system.

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.

(c) Turn the Techstream on.

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

(e) 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. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - ECM)

(a) Remove the No. 1 integration relay from the engine room relay block and junction block assembly.

(b) Disconnect the ECM connector.

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

Standard Resistance:





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

3. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - FUEL PUMP - BODY GROUND)

(a) Remove the No. 1 integration relay from the engine room relay block and junction block assembly.

(b) Disconnect the fuel pump connector.

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

Standard Resistance:





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

4. INSPECT FUEL PUMP

(a) Inspect the fuel pump Inspection.

HINT
Perform "Inspection After Repair" after replacing the fuel pump Programming and Relearning.

NG -- REPLACE FUEL PUMP Removal
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (BATTERY - NO. 1 INTEGRATION RELAY)

(a) Remove the No. 1 integration relay from the engine room relay block and junction block assembly.

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

Standard Voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE NO. 1 INTEGRATION RELAY

6. 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 and ECT / Data List / Primary / Starter Signal.

(e) Check the result when the ignition switch is ON and the engine starts.

OK





NG -- CHECK STARTER SIGNAL CIRCUIT Starter Signal Circuit
OK -- Continue to next step.

7. 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 and ECT / Data List / Primary / Engine Speed.

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

OK:

Values are displayed continuously.

NG -- CHECK CRANKSHAFT POSITION SENSOR CIRCUIT SFI System

OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures