Fuel Pump Control Circuit
2GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: Fuel Pump Control Circuit
Fuel Pump Control Circuit
DESCRIPTION
The FUEL PUMP relay switches the fuel pump speed according to the engine conditions. The fuel pump operates when the ECM receives the starter-operating signal (STA) and crankshaft-rotating signal (NE).
The FUEL PUMP relay is turned ON while the engine is idling or operating at low load. This causes current to flow through the fuel pump resistor to the fuel pump. The fuel pump then operates at low speed. The FUEL PUMP relay is turned OFF while the engine is cranking or operating at high load. The fuel pump then operates at normal speed.
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
1. CHECK FUEL PUMP
(a) Check if there is pressure in the fuel inlet hose.
HINT: If there is fuel pressure, you will hear the sound of fuel flowing.
OK -- INSPECT FUEL PUMP RESISTOR
NG -- Continue to next step.
2. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE C/OPEN RELAY)
(a) Connect The Techstream to the DLC3.
(b) Turn the ignition switch to ON and turn the Techstream or the OBD II scan tool main switch on.
(c) Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump / Speed.
(d) Check the relay operation while operating it using the Techstream.
Standard:
Operating noise can be heard from the relay.
OK -- CHECK ECM POWER SOURCE CIRCUIT ECM Power Source Circuit
NG -- Continue to next step.
3. INSPECT C/OPEN RELAY
(a) Remove the C/OPEN relay from the engine room R/B.
(b) Measure the resistance of the C/OPEN relay.
Standard resistance:
NG -- REPLACE C/OPEN RELAY
OK -- Continue to next step.
4. INSPECT ECM (FC VOLTAGE)
(a) Turn the ignition switch to ON.
(b) Measure the voltage of the ECM connectors.
Standard voltage:
OK -- REPLACE ECM
NG -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (ECM - C/OPEN RELAY)
(a) Disconnect the E5 ECM connector.
(b) Remove the C/OPEN relay from the engine room R/B.
(c) Measure the resistance between the terminals.
Standard resistance:
Check for open
Check for short
(d) Reconnect the ECM connector.
(e) Reinstall the C/OPEN relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (C/OPEN RELAY - IGNITION SWITCH)
(a) Reconnect the I14 ignition switch connector.
(b) Remove the C/OPEN relay from the engine room R/B.
(c) Measure the resistance between the terminals.
Standard resistance:
Check for open
Standard resistance:
Check for short
(d) Reconnect the ignition switch connector.
(e) Reinstall the C/OPEN relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
7. CHECK ECM POWER SOURCE CIRCUIT ECM Power Source Circuit
NG -- REPAIR OR REPLACE ECM POWER SOURCE CIRCUIT
OK -- Continue to next step.
8. INSPECT FUEL PUMP RELAY
(a) Remove the FUEL PUMP relay from the engine room R/B.
(b) Measure the FUEL PUMP relay resistance.
Standard resistance:
(c) Reinstall the fuel pump relay.
NG -- REPLACE FUEL PUMP RELAY
OK -- Continue to next step.
9. INSPECT FUEL PUMP
(a) Measure the resistance of the fuel pump.
(1) Measure the resistance between terminals 4 and 5.
Standard resistance:
(b) Check operation of the fuel pump.
(1) Apply battery voltage to both 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 ON and OFF the voltage on the battery side, not ON the fuel pump side.
NG -- REPLACE FUEL PUMP ASSEMBLY
OK -- Continue to next step.
10. CHECK HARNESS AND CONNECTOR (FUEL PUMP - FUEL PUMP RELAY, FUEL PUMP - BODY GROUND)
(a) Check the wire harness between the FUEL PUMP relay and fuel pump.
(1) Remove the FUEL PUMP relay from the engine room R/B.
(2) Disconnect the F16 fuel pump connector.
(3) Measure the resistance between the terminal of the wire harness side connectors and body ground.
Standard resistance:
(b) Check the wire harness between the fuel pump and body ground.
(1) Disconnect the F16 fuel pump connector.
(2) Measure the resistance between the terminal of the wire harness side connector and body ground.
Standard resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
11. CHECK HARNESS AND CONNECTOR (C/OPEN RELAY - FUEL PUMP RELAY)
(a) Remove the C/OPEN relay from the engine room R/B.
(b) Remove the FUEL PUMP relay from the engine room R/B.
(c) Measure the resistance between the terminals.
Standard resistance:
Check for open
Check for short
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - C/OPEN RELAY)
12. INSPECT FUEL PUMP RELAY
(a) Remove the FUEL PUMP relay from the engine room R/B.
(b) Measure the FUEL PUMP relay resistance.
Standard resistance:
(c) Reinstall the FUEL PUMP relay.
NG -- REPLACE FUEL PUMP RELAY
OK -- Continue to next step.
13. INSPECT FUEL PUMP RESISTOR
(a) Disconnect the F17 fuel pump resistor connector.
(b) Measure the fuel pump resistor resistance.
Standard resistance:
(c) Reconnect the fuel pump resistor connector.
NG -- REPLACE FUEL PUMP RESISTOR
OK -- Continue to next step.
14. CHECK HARNESS AND CONNECTOR (FUEL PUMP RELAY - FUEL PUMP RESISTOR)
(a) Disconnect the F17 fuel pump resistor connector.
(b) Remove the FUEL PUMP relay from the engine room R/B.
(c) Measure the resistance between the terminals.
Standard resistance:
Check for open
Check for short
(d) Reconnect the fuel pump resistor connector.
(e) Reinstall the FUEL PUMP relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
15. CHECK HARNESS AND CONNECTOR (FUEL PUMP RESISTOR - FUEL PUMP)
(a) Disconnect the F17 fuel pump resistor connector.
(b) Disconnect the F16 fuel pump connector.
(c) Measure the resistance between the terminals.
Standard resistance:
Check for open
Check for short
(d) Reconnect the fuel pump resistor connector.
(e) Reconnect the fuel pump connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE