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.
ECM Ground Circuits
ECM is located underneath top of passenger-side carpet (behind glove box) and is mounted to floor panel. Measure resistance between engine (ground) and specified terminals at ECM connector. See ECM GROUND CIRCUITS table. If resistance is more than one ohm, repair ground circuit. If resistance is one ohm or less, ground circuit is okay (ECM may be faulty).
| Application | ECM Connector (1) | (1) ECM Terminals No. (Wire Color) | ||||
|---|---|---|---|---|---|---|
| SC400 | "B" | 69 ((2) White/Red) | ||||
| SC400 | "B" | 78, 79 & 80 ((2) White/Black) | ||||
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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.