2009 Mercedes CL-Class Owner's Manual - Page 556

Practical hints Jump starting Jump starting G Warning! Failure to follow these directions will cause damage to the electronic components, and can lead to a battery explosion and severe injury or death. Never lean over batteries while connecting or jump starting. You might get injured. Battery fluid contains sulfuric acid. Do not allow this fluid to come in contact with eyes, skin or clothing. In case it does, immediately flush affected area with water, and seek medical help if necessary. A battery will also produce hydrogen gas, which is flammable and explosive. Keep flames or sparks away from battery, avoid improper connection of jumper cables, smoking, etc. Attempting to jump start a frozen battery can result in it exploding, causing personal injury. Read all instructions before proceeding. ! Do not tow-start the vehicle. You could otherwise seriously damage the automatic transmission which is not covered by the Mercedes-Benz Limited Warranty. ! Avoid repeated and lengthy starting attempts. Do not attempt to start the engine using a battery quick-charge unit. If the engine does not run after several unsuccessful starting attempts, have it checked at the nearest authorized Mercedes-Benz Center. Excessive unburned fuel generated by repeated failed starting attempts may damage the catalytic converter and may present a fire risk. Make sure the jumper cables do not have loose or missing insulation. Make sure the cable clamps do not touch any other metal part while the other end is still attached to a battery. If the battery is discharged, the engine can be started with jumper cables and the fully charged battery of another vehicle or an equivalent starter pack. Observe the following: RAccess to the battery is not possible on all vehicles. If you cannot access the battery in your vehicle provide jump start power by an external battery or starter pack. RJump starting should only be performed when the engine and catalytic converter are cold. not start the engine if the battery is frozen. Let the battery thaw out first. jump start from batteries with the same voltage rating (12 V). Jump starting with a more powerful battery could damage the vehicle's electrical system, which will not be covered by the Mercedes-Benz Limited Warranty. use jumper cables with sufficient cross-section and insulated terminal clamps. make sure the jumper cables are not on or near pulleys, fans or other parts that move when an engine is started or running. the battery be drained completely, let the donating power source charge the vehicle for several minutes before reattempting the starting process. RDo ROnly ROnly RAlways RShould X X Make sure the two vehicles do not touch. Switch off all electrical consumers. X Engage the electronic parking brake. 554