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.
Circuit/System Verification
With a scan tool, access Power Mode data display list and compare all parameters listed with the corresponding ignition key position. The Power Mode Parameters table below illustrates the correct state of these input parameters in correspondence to the S39 ignition switch position. The circuits which the individual parameters are related to are in parentheses.
| Ignition Switch Position | 5 V IGN (Ignition Switch, Terminal 4 and 6) |
Accessory (Ignition Switch, Terminal 3) |
Run/Crank (Ignition Switch, Terminal 1) |
|---|---|---|---|
| Off Key Out | Key Out/ACC | Inactive | Inactive |
| Off Key IN | Key In/Off | Inactive | Inactive |
| Accessory | Key Out/ACC | Active | Inactive |
| Run | Run | Active | Active |
| Start | Crank Request | Inactive | Active |
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.