Fuel Pump Control Circuit

1NR-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 is input to the STA terminal of the ECM, and 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 the transistor Tr1 in the ECM internal circuit ON. The current flows to the C/OPEN (Circuit Opening) relay by turning the Tr1 ON. Then, the fuel pump operates.

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

(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. INSPECT INTEGRATION RELAY (C/OPEN RELAY)





(a) Remove the integration relay.

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

Standard Resistance:





Text in Illustration





NG -- REPLACE INTEGRATION RELAY Removal
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM)

(a) Remove the integration relay.

(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.

4. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - FUEL PUMP - BODY GROUND)

(a) Remove the integration relay.

(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.

5. INSPECT FUEL PUMP

(a) Inspect fuel pump Inspection.

NG -- REPLACE FUEL PUMP Removal

OK -- REPLACE ECM Removal

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 / 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 / Engine Speed.

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

OK:

Values are displayed continuously.

NG -- CHECK CRANKSHAFT POSITION SENSOR CIRCUIT P0335

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