SFI SYSTEM Fuel Pump Control Circuit
| DTC Code | DTC Name |
|---|---|
| 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 Tr in the ECM internal circuit ON. The current flows to the C/OPN (Circuit Opening) relay by turning the Tr ON. Then, the fuel pump operates.
While the NE signal is input to the ECM with the engine running, the ECM turns the Tr on continuously.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
After replacing the ECM, perform idle learning.
Inspect the fuses for circuits related to this system before performing the following procedure.
PROCEDURE
PERFORM ACTIVE TEST USING GTS (CONTROL THE FUEL PUMP / SPEED)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump/Speed.
Powertrain > Engine and ECT > Active Test
Tester Display
Control the Fuel Pump / Speed
Check whether the fuel pump operating sound occurs when performing the Active Test on the GTS.
Result
Result
Proceed to
Fuel pump operating sound does not occur
A
Fuel pump operating sound occurs
B
B READ VALUE USING GTS (STARTER SIGNAL)Click here
INSPECT DRIVER SIDE JUNCTION BLOCK ASSEMBLY (C/OPN RELAY)
Remove the driver side junction block assembly.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection
Condition
Specified Condition
3B-1 - 3M-8
Battery voltage applied between terminals 3D-14 and 3J-7, and 3N-2 and 3D-13
Below 1 Ω
Battery voltage not applied between terminals 3D-14 and 3J-7, and 3N-2 and 3D-13
10 kΩ or higher
Result
Proceed to
OK
NG
CHECK HARNESS AND CONNECTOR (C/OPN RELAY - ECM)
Disconnect the driver side junction block assembly connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection
Condition
Specified Condition
3D-13 - A34-59 (FC)
Always
Below 1 Ω
3D-13 or A34-59 (FC) - Body ground
Always
10 kΩ or higher
Result
Proceed to
OK
NG
NG REPAIR OR REPLACE HARNESS OR CONNECTOR
CHECK HARNESS AND CONNECTOR (C/OPN RELAY - FUEL PUMP)
Disconnect the driver side junction block assembly connector.
Disconnect the fuel pump connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection
Condition
Specified Condition
3M-8 - K36-4 (B)
Always
Below 1 Ω
3M-8 or K36-4 (B) - Body ground
Always
10 kΩ or higher
Result
Proceed to
OK
NG
NG REPAIR OR REPLACE HARNESS OR CONNECTOR
CHECK HARNESS AND CONNECTOR (FUEL PUMP - BODY GROUND)
Disconnect the fuel pump connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection
Condition
Specified Condition
K36-5 (E) - Body ground
Always
Below 1 Ω
Result
Proceed to
OK
NG
NG REPAIR OR REPLACE HARNESS OR CONNECTOR
INSPECT FUEL PUMP
Inspect the fuel pump.
Result
Proceed to
OK
NG
READ VALUE USING GTS (STARTER SIGNAL)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Starter Signal.
Powertrain > Engine and ECT > Data List
Tester Display
Starter Signal
Check the result when the ignition switch is ON and the cranking.
OK
Condition
Starter Signal
Ignition switch ON
OFF
Cranking
ON
Result
Proceed to
OK
NG
READ VALUE USING GTS (ENGINE SPEED)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Engine Speed.
Powertrain > Engine and ECT > Data List
Tester Display
Engine Speed
Read the values displayed on the GTS while cranking.
OK
Values are displayed continuously.
Result
Proceed to
OK
NG