3.
Has a problem been found?
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Go to "Control Circuit Inspection" procedure.
The voltage after the fuel pump relay is used to supply power to the electric fuel pump in the low pressure line.
When the ignition switch is in starting position, the battery voltage is supplied from the fuel pump relay to the ECM.
When the ignition switch is turned on, current flows from the ignition switch through the current the fuel pump relay coil to ground by the ECM. And then, the voltage is supplied to the electric fuel pump to drive.
In case of the fuel pump relay failure, the engine symptoms will occur the running engine stall and the starting impossible.
If the signal exceeds threshold value, the ECM judged this as a fault and DTC is set.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Circuit continuity check | ● Contact resistance in connectors ● Short to battery in relay control circuit ● Fuse blown ● Faulty relay ● Faulty ECM |
Enable Conditions | ● Ignition on | |
Threshold Value | ● Short for relay control circuit | |
Diagnostic Time | ● 0.48 sec. | |
MIL Fuel Limit Fuel Cut EGR Off | ● No ● No ● No ● No |
Connect scantool to Data Link Cable (DLC).
Monitor " Fuel Pump Relay " parameter on the scantool.
Fig 1) Fuel pump relay is ON for approx. 3 seconds when turning the ignition switch ON.
Is the Current data displayed correctly ?
Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or was repaire and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
▶ Go to "W/Harness Inspection" procedure.
Many malfunctions in the electrical system are caused by poor harness and terminals.
Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Go to "Control Circuit Inspection" procedure.
Ignition "OFF".
Disconnect Fuel Pump Relay and ECM connector.
Igniton "ON" & Engine "OFF".
Measure voltage between terminal 3 of the fuel pump relay harness connector and chassis ground.
Specification : Approx. below 1V
Is the measured voltage within specifications ?
▶ Go to "Component inspection" procedure.
▶ Check for short to battery in control harness.
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Check Fuel Pump Relay
Ignition "OFF" & Engine "OFF"
Disconnect Fuel Pump Relay
Measure resistance between terminals 3 and 5 of the Fuel Pump Relay connector (Component side).
Specification : 90 ~ 100Ω (20°C)
Is the measured resistance within specifications ?
▶ Go to "Check Electric Fuel Pump Relay " as below.
▶ Substitute with a known-good Electric Fuel Pump Relay and check for proper operation.
If the problem is corrected, replace Electric Fuel Pump Relay and then go to "Verification of Vehicle Repair" procedure.
Check Electric Feul Pump Relay operation
Ignition "OFF" & Engine "OFF".
Connect Fuel Pump relay and Disconnect ECM connector.
Ignition "ON" & Engine "OFF".
Ground terminal 24 of ECM harness connector to operate Fuel Pump Relay. Or, Use Actuator Test mode in scantool to operate Electric Fuel Pump Relay.
Is the Fuel Pump Relay operating corrctly ?
▶ Go to "Check Fuel Pump Power Circuit" as below.
▶ Substitute with a known-good Fuel Pump Relay and check for proper operation.
If the problem is corrected, replace Fuel Pump Relay and then go to "Verification of Vehicle Repair" procedure.
Check Electric Feul Pump Power Circuit
Ignition "OFF" & Engine "OFF".
Disconnect Fuel Pump relay.
Jump terminal 2 and 4 of Fuel Pump Relay harness connector with jumper wire.
Is operating sound of the Fuel Pump heard ?
▶ Substitute with a known-good Fuel Pump Relay and check for proper operation.
If the problem is corrected, replace Fuel Pump Relay and then go to "Verification of Vehicle Repair" procedure.
▶ Substitute with a known-good ECM and check for proper operation.
If the problem is corrected, replace ECM and then go to "Verification of Vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode and then clear DTC.
Operate the vehicle within DTC Enable conditions in General information.
Are any DTCs present ?
Go to the applicable troubleshooting procedure.
System is performing to specification at this time.
