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
- Check voltage between terminals +B and E1 of ECM connectors.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals +B and E1 of the ECM connectors.
OK:
- Voltage: 9 to 14 V
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- OK: Proceed to next circuit inspection shown on problem symptoms table (See PROBLEM SYMPTOMS TABLE ).
- NG: Go to Next Step
- Check for open in harness and connector between terminal E1 of ECM and body ground (See HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
).
- NG: Repair or replace harness or connector.
- OK: Go to Next Step
- Check voltage between terminal IGSW of ECM connector and body ground.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal IGSW of the ECM connector and body ground.
OK:
- Voltage: 9 to 14 V
- OK: Go to step 6 .
- NG: Go to Next Step
- Check IGN fuse.
PREPARATION:
Remove the IGN fuse from the cowl side J/B RH.
CHECK:
Check the continuity of the IGN fuse.
OK:
- Continuity
- NG: Check for short in all harness and components connected to IGN fuse.
- OK: Go to Next Step
- Check ignition switch (See IGNITION SWITCH & KEY UNLOCK WARNING SWITCH
).
- NG: Replace ignition switch.
- OK: Check and repair harness and connector between battery and ignition switch, and ignition switch and ECM (See HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS ).
- Check voltage between terminal MREL of ECM connector and body ground.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal MREL of the ECM connector and body ground.
OK:
- Voltage: 9 to 14 V
- NG: Replace ECM (See INSPECTION ).
- OK: Go to Next Step
- Check EFI or ECD No. 1 fuse of engine room J/B.
PREPARATION:
Remove the EFI or ECD No. 1 fuse from the engine room J/B.
CHECK:
Check continuity of EFI or ECD No. 1 fuse.
OK:
- Continuity
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- NG: Check for short in all harness and components connected to EFI or ECD No. 1 fuse.
- OK: Go to Next Step
- Check EFI or ECD relay (See removal under EFI MAIN RELAY
).
- NG: Replace EFI or ECD relay.
- OK: Go to Next Step
- Check for open and short in harness and connector between terminal MREL of ECM and body ground (See HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
).
- NG: Repair or replace harness or connector.
- OK: Check and repair harness or connector between EFI or ECD No. 1 fuse and battery (See HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS ).
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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