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.
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HOMESERVICE MANUALSTOYOTA1991SUPRA L6-3.0L DOHC TURBO (7M-GTE)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSRELAYS AND MODULES - COMPUTERS AND CONTROL SYSTEMSMAIN RELAY (COMPUTER/FUEL SYSTEM)DIAGRAMSEFI MAIN RELAY
1991 Toyota Supra L6-3.0L DOHC Turbo (7M-GTE)
EFI Main Relay
1991 Toyota Supra L6-3.0L DOHC Turbo (7M-GTE)SECTION EFI Main Relay
1. Unplug the EFI Main Relay from the fuse panel.
2. Using an Ohmmeter, check for continuity between terminals 1 and 3.
3. Check that there is NO continuity between terminals 2 and 4 or terminals 3 and 4.
4. If not as specified, replace the EFI Main Relay.
5. Apply battery current across terminals 1 and 3.
6. Using an Ohmmeter, check for continuity between terminals 2 and 4.
7. If operation is not as specified, replace the EFI Main Relay.
8. Remove the battery leads and reinstall the relay.
NOTE: Refer to ECU POWER SUPPLY for circuit test of the EFI Main Relay.
2. Using an Ohmmeter, check for continuity between terminals 1 and 3.
Testing EFI Relay:
3. Check that there is NO continuity between terminals 2 and 4 or terminals 3 and 4.
4. If not as specified, replace the EFI Main Relay.
5. Apply battery current across terminals 1 and 3.
Testing EFI Relay Operation - Current Applied:
6. Using an Ohmmeter, check for continuity between terminals 2 and 4.
7. If operation is not as specified, replace the EFI Main Relay.
8. Remove the battery leads and reinstall the relay.
NOTE: Refer to ECU POWER SUPPLY for circuit test of the EFI Main Relay.
RENDER: 1.0x
NO RELATED
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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.