Toyota Prius Smart Key System

Gen 2 Smart Key System Doors Won’t Unlock

This example is from a 2004 Toyota Prius that has about a 140k on it. The complaint is that the customer could not open the door. The tow truck driver pulled vehicle up onto a flat bed skidding the front tires and dropped car the same way. The Vehicle is equipped with a Smart Key and the owner of the vehicle nor the tow truck driver are familiar with the system. The Smart Key automatically unlocks the car doors when the driver touches the pad on the inside of the driver’s door handle assuming that the 12 volt battery is functional. The twelve volt battery is located in the rear hatch area and the rear hatch will not open from the outside without a key. There appears to be no key although there is a keyhole in the driver’s door but no key hole in the deck lid.The technician uses the hidden key to unlock the driver’s door.

Toyota Prius Hidden Key

Toyota Prius Hidden Key. If there is a black emblem it’s a non-proximity system and silver emblem is a proximity system.

To get to the Prius 12 volt battery you have two options:

  • He can reach over the back seat, drag out the flooring material, climb into the back and use the hidden latch button to unlatch the deck lid.
  • A second, and better solution is to open the hood and jumper power using the underhood jump location.
Hybrid Battery Jumper Location

Toyota Prius 12 volt battery jumper location.

Hybrid Battery Jumper Location

Toyota Prius 12 volt battery jumper location.

The moral of the story is to always check the Absorbed Glass Mat (AGM) Auxiliary Battery condition on both Gen 1 and Gen 2 Prius even though it is difficult to access in it’s location under the lining in the back hatch area. When testing an AGM type battery always Use a Capacitance type battery tester.

This post was written by: Martin Hand


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About Martin Hand

ASE Certified L1 Advanced Mastertech. Martin Hand has over 15 years experience in Asian and European Import Auto Repair. Specializing in electrical diagnosis, engine performance, AT/MT transmission repair/rebuild. Martin is also pursuing a degree in Computers Science & Information Systems starting at Portland Community College while he plans to transfer to OIT. Certified in Java application level programming, experienced with other languages such as PHP, Ruby, JavaScript and Swift. Martin has future plans of automotive diagnostic software development.

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