Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Inspection Procedure
- PERFORM ACTIVE TEST BY INTELLIGENT TESTER (OPERATION OF CIRCUIT OPENING RELAY)
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch ON and turn the tester ON.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / FUEL PUMP / SPD.
- Check whether operating sounds can be heard while operating the relay using the tester.
OK: Operating sounds can be heard from relay.
OK : Go to step 7
NG : GO TO NEXT STEP
- INSPECT ECM POWER SOURCE CIRCUIT
- Inspect the ECM power source circuit (see INSPECTION PROCEDURE ).
NG : REPAIR OR REPLACE
OK : GO TO NEXT STEP
- INSPECT CIRCUIT OPENING RELAY (Marking: C/OPN)
- Remove the circuit opening relay from the instrument panel junction block.
- Measure the resistance of the circuit opening relay.
Standard resistance
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition 3 - 5 10 kΩ or higher 3 - 5 Below 1 Ω (when battery voltage is applied to terminals 1 and 2)
NG : REPLACE CIRCUIT OPENING RELAY
OK : GO TO NEXT STEP
- INSPECT ECM (FC VOLTAGE)
- Turn the ignition switch ON.
- Measure the voltage of the ECM connectors.
Standard voltage
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition FC (E6-25) - E01 (E3-7) 9 to 14 V
OK : REPLACE ECM
NG : GO TO NEXT STEP
- CHECK HARNESS AND CONNECTOR (EFI RELAY (Marking: EFI) - CIRCUIT OPENING RELAY (Marking: C/OPN)
- Remove the EFI relay from the engine room relay block.
- Remove the circuit opening relay from the instrument panel junction block.
- Measure the resistance of the wire harness side connectors.
Standard resistance (Check for open)
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition Engine room relay block (EFI relay terminal 3) - Instrument panel junction block (Circuit opening relay terminal 1) Below 1 Ω Engine room relay block (EFI relay terminal 3) - Instrument panel junction block (Circuit opening relay terminal 5) Below 1 Ω Standard resistance (Check for short)
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition Engine room relay block (EFI relay terminal 3) or Circuit opening relay (1) - Body ground 10 kΩ or higher Instrument panel junction block (Circuit opening relay terminal 5) - Body ground 10 kΩ or higher
NG : REPAIR OR REPLACE HARNESS OR CONNECTOR
OK : GO TO NEXT STEP
- CHECK HARNESS AND CONNECTOR (ECM - CIRCUIT OPENING RELAY)
- Disconnect the E6 ECM connector.
- Remove the circuit opening relay from the instrument panel junction block.
- Measure the resistance of the wire harness side connectors.
Standard resistance (Check for open)
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition FC (E6-25) - Instrument panel junction block (Circuit opening relay terminal 2) Below 1 Ω Standard resistance (Check for short)
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition FC (E6-25) or Instrument panel junction block (Circuit opening relay terminal 2) - Body ground 10 kΩ or higher
NG : REPAIR OR REPLACE HARNESS OR CONNECTOR
OK : REPLACE ECM
- INSPECT FUEL PUMP
- Inspect the fuel pump (see INSPECTION ).
NG : REPLACE FUEL PUMP
OK : GO TO NEXT STEP
- CHECK HARNESS AND CONNECTOR (CIRCUIT OPENING RELAY (Marking: C/OPN) - FUEL PUMP, FUEL PUMP - BODY GROUND)
- Remove the circuit opening relay from the instrument panel junction block.
- Disconnect the F15 fuel pump connector.
- Measure the resistance of the wire harness side connectors.
Standard resistance (Check for open)
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition Instrument panel junction block (Circuit opening relay terminal 3) - Fuel pump (F15-4) Below 1 Ω Fuel pump (F15-5) - Body ground Below 1 Ω Standard resistance Check for short)
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Specified Condition Instrument panel junction block (Circuit opening relay terminal 3) or Fuel pump (F15-4) - Body ground 10 kΩ or higher
NG : REPAIR OR REPLACE HARNESS OR CONNECTOR
OK : REPLACE ECM
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.
