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
- INSPECT ECM (+B VOLTAGE)
- Turn the ignition switch to the ON position.
- Measure the voltage between the terminals of the E3 and E6 ECM connectors.
Standard voltage
TESTER CONNECTIONS AND SPECIFIED CONDITIONSTester Connections Specified Conditions +B (E6-1) - E1 (E3-5) Between 9 V and 14 V
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG: Go to next step
- CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)
- Disconnect the negative battery cable.
- Disconnect the E3 ECM connector.
- Check the resistance.
Standard resistance (Check for open)
TESTER CONNECTIONS AND SPECIFIED CONDITIONSTester Connections Specified Conditions E1 (E3-5) - Body ground Below 1 Ω - Reconnect the ECM connector.
- Reconnect the negative battery cable.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- INSPECT ECM (IGSW VOLTAGE)
- Turn the ignition switch to the ON position.
- Measure the voltage between the terminals of the E3 and E6 ECM connectors.
Standard voltage
TESTER CONNECTIONS AND SPECIFIED CONDITIONSTester Connections Specified Conditions IGSW (E6-9) - E1 (E3-5) Between 9 V and 14 V
OK: Go to step 6
NG: Go to next step
- CHECK FUSE (AM2 FUSE)
- Remove the AM2 fuse from the instrument panel J/B.
- Check the AM2 fuse resistance.
Standard resistance:
Below 1 Ω
- Reinstall the AM2 fuse.
NG: CHECK FOR SHORTS IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE
OK: Go to next step
- INSPECT IGNITION OR STARTER SWITCH ASSEMBLY
- Disconnect the I11 ignition switch connector.
- Check the resistance.
Standard resistance
TESTER CONNECTIONS AND SPECIFIED CONDITIONSIgnition Switch Positions Tester Connections Specified Conditions LOCK All Terminals 10 kΩ or higher ACC 1-3 Below 1 Ω ON 1-2, 1-3, 2-3, 5-6 Below 1 Ω START 1-2, 4-5, 4-6, 5-6 Below 1 Ω - Reconnect the ignition switch connector.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE IGNITION OR STARTER SWITCH ASSEMBLY
OK: CHECK AND REPAIR HARNESS AND CONNECTOR (BATTERY - IGNITION SWITCH, IGNITION SWITCH - ECM)
- INSPECT ECM (MREL VOLTAGE)
- Turn the ignition switch to the ON position.
- Measure the voltage between the terminals of the E3 and E6 ECM connectors.
Standard voltage
TESTER CONNECTIONS AND SPECIFIED CONDITIONSTester Connections Specified Conditions MREL (E6-8) - E1 (E3-5) Between 9 V and 14 V
NG: REPLACE ECM
OK: Go to next step
- CHECK FUSE (EFI AND EFI2)
- Remove the EFI and EFI2 fuses from the engine room R/B.
- Check the EFI and EFI2 fuses resistance.
Standard resistance:
Below 1 Ω
- Reinstall the EFI and EFI2 fuses.
NG: CHECK FOR SHORTS IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE
OK: Go to next step
- INSPECT EFI RELAY
- Remove the EFI relay from the engine room R/B.
- Check the EFI relay resistance.
Standard resistance
TESTER CONNECTIONS AND SPECIFIED CONDITIONSTester Connections Specified Conditions 3 - 5 10 Ω or higher 3 - 5 Below 1 Ω (when battery voltage is applied to terminals 1 and 2) - Reinstall the EFI relay.
NG: REPLACE EFI RELAY
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (EFI RELAY - ECM, EFI RELAY - BODY GROUND)
- Check the harness and connector between the EFI relay and ECM.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Remove the EFI relay from the engine room R/B.
- Disconnect the E6 ECM connector.
- Check the resistance.
Standard resistance (Check for open)
TESTER CONNECTIONS AND SPECIFIED CONDITIONSTester Connections Specified Conditions Engine room R/B (EFI relay terminal 1) - MREL (E6-8) Below 1 Ω Engine room R/B (EFI relay terminal 3) - +B (E6-1) Below 1 Ω Standard resistance (Check for short)
TESTER CONNECTIONS AND SPECIFIED CONDITIONSTester Connections Specified Conditions Engine room R/B (EFI relay terminal 1) or MREL (E6-8) - Body ground 10 kΩ or higher Engine room R/B (EFI relay terminal 3) or +B (E6-1) -Body ground 10 kΩ or higher - Reconnect the ECM connector.
- Reinstall the EFI relay.
- Check the harness and connector between the EFI relay and body ground.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: CHECK HARNESS AND CONNECTOR (TERMINAL 5 OF EFI RELAY - BATTERY POSITIVE TERMINAL)
- Check the harness and connector between the EFI relay and ECM.
Use the Manual With the Right Hardware
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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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