TOYOTA 2010 Yaris - Manual (Page 352)

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5-2. Steps to take in an emergency
Connecting the jumper cables
Positive (+) battery terminal on your vehicle
Positive (+) battery terminal on the second vehicle
Negative (-) battery terminal on the second vehicle
Connect the jumper cable to ground on your vehicle as shown in
the illustration.
Start the engine of the second vehicle. Increase the engine
speed slightly and maintain at that level for approximately 5
minutes to recharge the battery of your vehicle.
Maintain the engine speed of the second vehicle and start
the vehicle's engine.
Once the vehicle’s engine has started, remove the jumper
cables in the exact reverse order in which they were con-
nected.