You have just received your first hybrid electric vehicle into your repair facility. The vehicle is damaged to a point where you know the high voltage components will need to be removed or replaced. This leaves a lot of uncertainty for a technician that is unfamiliar with the voltage systems and a shop owner that realizes that a slip-up could be costly or even lethal.
My suggestion is become familiar with hybrids! Courses from I-Car and NSCC review actual collision damage to vehicles during their seminars; information that is critical. Starting to repair any part of today’s vehicles without proper information is like trying to put together a model without instructions. Hybrids’ high voltage batteries do not give you a second chance with voltages 300+DC (direct current) ranges.
What becomes even more frustrating is when a hybrid like the Prius comes in and it won’t run. These CVT transmissions do not have a conventional gear box and this means they are electronically controlled. If you disconnect or remove the 12 volt battery, you will not be able to put the car back into gear or neutral without powering up the vehicle.
This can be a pain if the vehicle needs to be moved about the shop so we have included a procedure you can use to keep a hybrid Prius mobile in your shop when all electrical is disabled.
So let’s start with the park lock on a hybrid Toyota. This is controlled by a device known as a “shift control actuator.” This actuator controls the park mechanism in the transmission. While this actuator is electrically operated, it only operates on 12 volts separate from the high voltage system for the motors. The transmission ECU activates the actuator when the park button is pushed on the dash, this engages the park leaver on the transmission. If the vehicle is in “drive” and the start power button is depressed, even if it’s still in the drive or neutral positions, it will automatically go into “park”. So you can leave it in neutral but the power button will have to be on.
So the best way to “push a Prius” and make it so you can have the vehicle mobile with all power disconnected, is to start with locating the AGM or 12 volt low voltage battery in the right rear trunk area. Remove the covers and loosen the negative battery cable but don’t remove it. Now power up the car and put the vehicle into neutral (note you do not need the high voltage system enabled for this).
Place the vehicle into the neutral position for 30 seconds then disconnect the 12 volt battery without turning the car off. This will cause the shift control actuator to stay in the neutral position and when the battery is disconnected the automatic park will be disabled. Reconnecting the 12 volt battery will automatically engage the park control and the car will go back into park.
Hybrid vehicles are worlds away from typical vehicles. It’s wise to keep yourself up-to-date with the latest available information as these will be the cars of the future.
Much, much more in the print addition of Auto Atlantic.
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