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.
Code 3-1-1 (Speedometer Signal)
Turn ignition off. Remove panel under instrument panel on driver's side. Disconnect 12-pin connector from speedometer. On 240 Series, connect an ohmmeter between Blue/Black wire of speedometer connector and terminal No. 34 (Blue/Black wire) of fuel system ECU. On all others, connect ohmmeter between Violet/White wire of speedometer connector and terminal No. 34 (Violet/White wire) of fuel system ECU. Resistance should be zero ohms. If resistance is present, check wiring and connectors. If problem persists, check speedometer operation and related wiring.
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.