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 MANUALSTOYOTA19904RUNNER 2D UTILITY, 2.4 R, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTCRUISE CONTROL SYSTEMSCIRCUIT TESTINGPOWER SOURCE CIRCUIT
1990 Toyota 4Runner 2D Utility, 2.4 R, Automatic
Power Source Circuit
1990 Toyota 4Runner 2D Utility, 2.4 R, AutomaticSECTION Power Source Circuit
- Check ECU-IG fuse and replace if faulty. If fuse is okay, go to next step. If fuse failure is continuous, disconnect cruise control Electronic Control Unit (ECU) wire harness connector. Install NEW fuse. Turn ignition on and check fuse. If fuse fails, check for short circuit in wire harness. If fuse is okay, replace ECU.
- Disconnect ECU wire harness connector. Check for continuity between ECU ground terminal and body ground. See ECU CONNECTOR GROUND & POWER TERMINAL IDENTIFICATION table. See Fig 1. for ECU connector terminal identification. If continuity is not present, repair open in circuit. If continuity is present, go to next step.
- Turn ignition on. Measure voltage between power terminal and ground. See ECU CONNECTOR GROUND & POWER TERMINAL IDENTIFICATION table. If battery voltage is not present, repair open in circuit. If battery voltage is present, replace ECU.
ECU CONNECTOR GROUND & POWER TERMINAL IDENTIFICATION
| Application Type | Ground Terminal | Power Terminal |
|---|---|---|
| Pickup & 4Runner | 15 | 12 |
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.