2008 Toyota Prius Owners Manual - Page 403

4-3. Do-it-yourself maintenance n Before recharging When recharging, the 12 volt battery produces hydrogen gas which is flammable and explosive. Therefore, before recharging: l If recharging with the 12 volt battery installed on the vehicle, be sure to disconnect the ground cable. l Make sure the power switch on the charger is off when connecting and disconnecting the charger cables to the 12 volt battery. n After recharging/reconnecting the 12 volt battery In some cases, the hybrid system may not start. Follow one or both of the following procedures: l After opening and closing the driver's door, wait 10 seconds then attempt to start the engine. (If the system does not start first time, repeat the procedure.) l With the shift lever in "P" and the "POWER" switch in the OFF mode, open and close any door, then attempt to start the hybrid system. If the system will not start even after multiple attempts at both methods, contact your Toyota dealer. 376 PRIUS_U_(L/O_0802)