1998 Lexus SC 400 Owners Manual - Page 219

IN CASE OF AN EMERGENCY 2. If required, remove all the vent plugs from the booster battery. Lay a cloth over the open vents on the booster battery. (This helps reduce the explosion hazard, personal injuries and burns.) 3. If the engine in the vehicle with the booster battery is not running, start it and let it run for about 5 minutes. During jump starting, run the engine at about 2000 rpm with the accelerator pedal lightly depressed. 4. Connect the jumper cables in the exact order shown in the illustration: positive terminal ("+" mark)-to-positive terminal ("+" mark), and negative terminal ("-" mark)-to-engine or body ground. Note that you first connect the positive cable to the discharged battery and then to the booster battery. Next, connect the negative cable to the booster battery and then to a solid, stationary, unpainted metallic point (e.g. SC400: brake booster vacuum pipe bracket, SC300: cylinder head) away from the battery. Do not connect it to or near any part that moves when the engine is cranked. CAUTION When making the connections, to avoid serious injury, do not lean over the battery or accidentally let the jumper cables or clamps touch anything except the correct battery terminals or the ground. 5. Start your engine in the normal way. After starting, run it at about 2000 rpm for several minutes with the accelerator pedal lightly depressed. 6. Carefully disconnect the cables in the exact reverse order: the negative cable and then the positive cable. 7. Carefully dispose of the battery cover cloths which may now contain sulfuric acid. 8. If removed, replace all the battery vent plugs. If the cause of your battery discharging is not apparent (for example, lights left on), you should have it checked. IF YOUR VEHICLE OVERHEATS If your engine coolant temperature gauge indicates overheating, if you experience a loss of power, or if you hear a loud knocking or pinging noise, the engine has probably overheated. 202