Step 2 - Diagnosis System

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

Description
- The HV control ECU has a self-diagnosis system by which malfunction in the computer itself or in THS components is detected and the Hybrid vehicle warning light in the multi-information display are lighted up.
  
  Fig 1: Identifying Power Steering, Hybrid Vehicle Battery & Hybrid System Warning Lights
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- To check the Diagnostic Trouble Codes (DTC), connect the hand-held tester to the Data Link Connector 3 (DLC3) on the vehicle. The TOYOTA hand-held tester also enables you to erase the DTC and check freeze frame data and various forms of THS data.
  
  Fig 2: Connecting Hand Held Tester To DLC3
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Freeze frame data:
  As the freeze frame data records the driving condition when a malfunction is detected, when troubleshooting, it is useful for determining whether the vehicle was running, braked, stopped or reversed.
Check the DLC3.
The HV control ECU conforms to ISO 14230 for communication.

The terminal arrangement of the DLC3 complies with SAEJ1962 and matches the ISO 14230 format.

Fig 3: Identifying DLC3 Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 4: DLC3 Terminal Specifications
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NOTE:
If your display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the TOYOTA hand-held tester to the DLC3, turned the motor switch ON and operated the tester, there is a problem in the vehicle or tool.
- If communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle.
- If communication is still not possible when the tool is connected to another vehicle, the problem is probably in the tool itself, so consult the Service Department.