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 (FUEL PUMP SPEED)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch ON 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 operating sound occurs when performing the Active Test on the tester.
OK:
Fuel pump operating sound occurs.
OK -- READ VALUE USING TECHSTREAM (STARTER SIG)
NG -- Continue to next step.
2. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (C/OPN RELAY INPUT VOLTAGE)
(a) Measure the voltage between the terminal of the instrument panel Junction Block (J/B) and the body ground when the ignition switch is turned ON and OFF.
Standard voltage:
OK -- INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (C/OPN RELAY)
NG -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL J/B - INTEGRATION RELAY, IG2 RELAY)
(a) Remove the integration relay and IG2 relay from the engine room No. 1 relay block.
(b) Disconnect the instrument panel junction block connector.
(c) Check the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reinstall the integration relay and IG2 relay.
(e) Reconnect the instrument panel junction block connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- GO TO ECM POWER SOURCE CIRCUIT
4. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (C/OPN RELAY)
(a) Remove the instrument panel junction block.
(b) Measure the C/OPN relay resistance.
Standard resistance:
HINT: Relay coil circuit between IF-4 and IE-5 is not through IGN fuse.
(c) Reinstall the instrument panel junction block.
NG -- REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL J/B - ECM)
(a) Disconnect the A9 ECM connector.
(b) Disconnect the IE connector from instrument panel junction block.
(c) Measure the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the instrument panel junction block and the ECM connectors.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
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 instrument panel junction block assembly and the fuel pump.
(1) Disconnect the IA instrument panel junction block connector.
(2) Disconnect the S1 fuel pump connector.
(3) Measure the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(b) Check the harness and the connectors between the fuel pump and the body ground.
(1) Disconnect the S1 fuel pump connector.
(2) Measure the resistance.
Standard resistance (Check for open):
(c) Reconnect the instrument panel junction block connector.
(d) Reconnect the fuel pump connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
7. INSPECT FUEL PUMP
(a) Inspect fuel pump resistance.
(1) Measure the resistance between the terminals.
Standard resistance:
0.2 to 3.0 Ohms at 20°C(68°F)
(b) Inspect fuel pump operation.
(1) Apply the battery voltage to both the terminals. Check that the pump operates.
NOTICE:
- These tests must be done quickly (within 10 seconds) to prevent the coil from burning out.
- Keep the fuel pump as far away from the battery as possible.
- Always turn the voltage on and off on the battery side, not the fuel pump side.
NG -- REPLACE FUEL PUMP
OK -- REPLACE ECM
8. READ VALUE USING TECHSTREAM (STARTER SIG)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch ON and turn the tester ON.
(c) Select the following menu items: Powertrain / Engine and ECT / Data List / Starter Signal.
(d) Check the result when the ignition switch is turned to ON and START.
OK:
NG -- REPAIR OR REPLACE STARTING SYSTEM
OK -- Continue to next step.
9. READ VALUE USING TECHSTREAM (ENGINE SPEED)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch ON and turn the tester ON.
(c) Select the following menu items: Powertrain / Engine and ECT / Data List / Engine Speed.
(d) Read the values displayed on the tester while cranking.
Standard:
Values are displayed continuously.
NG -- REPAIR OR REPLACE CRANKSHAFT POSITION SENSOR CIRCUIT
OK -- REPLACE ECM