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
When using intelligent tester:
- PERFORM ACTIVE TEST BY INTELLIGENT TESTER (OPERATION OF CIRCUIT OPENING RELAY)
- Connect an intelligent tester to the DLC3.
- Turn the ignition switch to ON and turn the tester ON.
- Select the following menu items: 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 6
NG: GO TO NEXT STEP
- INSPECT ECM POWER SOURCE CIRCUIT
- Inspect the ECM POWER SOURCE CIRCUIT .
NG: REPAIR OR REPLACE ECM POWER SOURCE CIRCUIT
OK: GO TO NEXT STEP
- INSPECT CIRCUIT OPENING RELAY
- Remove the circuit opening relay from the instrument panel J/B.
- Check the circuit opening relay resistance.
Standard resistance
RESISTANCE SPECIFIED CONDITIONSTester Connections Specified Conditions 3 - 5 10 k or higher 3 - 5 Below 1 (when battery voltage applied to terminals 1 and 2) - Reinstall the circuit opening relay.
NG: REPLACE CIRCUIT OPENING RELAY
OK: GO TO NEXT STEP
- INSPECT ECM (FC VOLTAGE)
- Turn the ignition switch to ON.
- Measure the voltage between the terminals of the E3 and E5 ECM connectors.
Standard voltage
VOLTAGE SPECIFIED CONDITIONSTester Connections Specified Conditions FC (E5-16) - E01 (E3-7) Between 9 V and 14 V
OK: REPLACE ECM
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NG: GO TO NEXT STEP
- CHECK HARNESS AND CONNECTOR (EFI RELAY - CIRCUIT OPENING RELAY)
- Disconnect the EFI relay from the engine room R/B.
- Remove the circuit opening relay from the instrument panel J/B.
- Measure the resistance.
Standard resistance (Check for open)
RESISTANCE SPECIFIED CONDITIONS (FOR OPEN)Tester Connections Specified Conditions EFI relay (1) - Circuit opening relay (1) Below 1 EFI relay (3) - Circuit opening relay (5) Below 1 Standard resistance (Check for short)
RESISTANCE SPECIFIED CONDITIONS (FOR SHORT)Tester Connections Specified Conditions EFI relay (1) or Circuit opening relay (1) - Body ground 10 k or higher EFI relay (3) or Circuit opening relay (5) - Body ground 10 k or higher - Reinstall the circuit opening relay.
- Reinstall the EFI relay.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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 - FUEL PUMP, FUEL PUMP - BODY GROUND)
- Remove the circuit opening relay from the instrument panel J/B.
- Disconnect the F10 fuel pump connector.
- Measure the resistance.
Standard resistance (Check for open)
RESISTANCE SPECIFIED CONDITIONS (FOR OPEN)Tester Connections Specified Conditions Circuit opening relay (3) - Fuel pump (F10-4) Below 1 Fuel pump (F10-5) - Body ground Below 1 Standard resistance (Check for short)
RESISTANCE SPECIFIED CONDITIONS (FOR SHORT)Tester Connections Specified Conditions Circuit opening relay (3) or Fuel pump (F10-4) - Body ground 10 k or higher - Reconnect the fuel pump connector.
- Reinstall the circuit opening relay.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK: REPLACE ECM
When Using OBD II Scan Tool:
- CHECK FUEL PUMP (OPERATION)
- Turn the ignition switch to ON.
- Connect terminals FC and E01 of the ECM connector.
- Measure for fuel pump operating sounds.
Result: Operating sounds can be heard from fuel pump.
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: GO TO NEXT STEP
- INSPECT ECM POWER SOURCE CIRCUIT
- Inspect the ECM POWER SOURCE CIRCUIT .
NG: REPAIR OR REPLACE ECM POWER SOURCE CIRCUIT
OK: GO TO NEXT STEP
- INSPECT CIRCUIT OPENING RELAY
- Remove the circuit opening relay from the instrument panel J/B.
- Measure the circuit opening relay resistance.
Standard resistance
RESISTANCE SPECIFIED CONDITIONSTester Connections Specified Conditions 3 - 5 10 k or higher 3 - 5 Below 1 (when battery voltage is applied to terminals 1 and 2) - Reinstall the circuit opening relay.
NG: REPLACE CIRCUIT OPENING RELAY
OK: GO TO NEXT STEP
- INSPECT ECM (FC VOLTAGE)
- Turn the ignition switch to ON.
- Measure the voltage between the terminals of the E3 and E5 ECM connectors.
Standard voltage
VOLTAGE SPECIFIED CONDITIONSTester Connections Specified Conditions FC (E5-16) - E1 (E3-7) Between 9 V and 14 V
OK: REPLACE ECM
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: GO TO NEXT STEP
- CHECK HARNESS AND CONNECTOR (EFI RELAY - CIRCUIT OPENING RELAY)
- Remove the EFI relay from the engine room R/B.
- Remove the circuit opening relay from the instrument panel J/B.
- Measure the resistance.
Standard resistance (Check for open)
RESISTANCE SPECIFIED CONDITIONS (FOR OPEN)Tester Connections Specified Conditions EFI relay (1) - Circuit opening relay (1) Below 1 EFI relay (1) - Circuit opening relay (5) Below 1 Standard resistance (Check for short)
RESISTANCE SPECIFIED CONDITIONS (FOR SHORT)Tester Connections Specified Conditions EFI relay (1) or Circuit opening relay (1) - Body ground 10 k or higher EFI relay (3) or Circuit opening relay (5) - Body ground 10 k or higher - Reinstall the circuit opening relay.
- Reinstall the EFI relay.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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 - FUEL PUMP, FUEL PUMP - BODY GROUND)
- Remove the circuit opening relay from the instrument panel J/B.
- Disconnect the F10 fuel pump connector.
- Measure the resistance.
Standard resistance (Check for open)
RESISTANCE SPECIFIED CONDITIONS (FOR OPEN)Tester Connections Specified Conditions Circuit opening relay (3) - Fuel pump (F10-4) Below 1 Fuel pump (F10-5) - Body ground Below 1 Standard resistance (Check for short)
RESISTANCE SPECIFIED CONDITIONS (FOR SHORT)Tester Connections Specified Conditions Circuit opening relay (3) or Fuel pump (F10-4) - Body ground 10 k or higher - Reconnect the fuel pump connector.
- Reinstall the circuit opening relay.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK: REPLACE ECM
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
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