LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2004 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 433 (HV Battery Control System - Diagnostics) >> Pre-Check
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Section 433 (HV Battery Control System - Diagnostics): Pre-Check

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.
  1. Precaution:
    1. To distinguish a trouble and replace a defective part, take necessary preventive measures against an electric shock. See REPAIR INSTRUCTIONS .
    2. Some portions of the wiring harness in the THS vehicle have the circuits, to which a high voltage is applied. To prevent an electrical shock, be sure to observe the following:
      1. Wear insulated gloves during inspection.
      2. Remove a service plug and do not start any repair operation before 5 minutes have passed, then confirm that the voltage at the output terminals has dropped down to 12 V or less.
      3. Use insulated tools during inspection.
      4. When disengaging wiring connectors, hold the connector bodies to avoid pulling the wires. When engaging wiring connectors, be sure to engage them securely.
        Fig 1: Identifying Service Plug & Service Plug Assembly
        G01112743Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Do not leave tools or parts (bolts, nuts, etc.) inside the cabin.
    4. Do not carry metallic objects such as mechanical pencils or scales.
  2. Diagnosis system:
    1. Description
      • The HV Battery ECU has a self-diagnosis system by which malfunction in the computer itself or in Hybrid System is detected and the master warning light in the combination meter and the Hybrid system warning light in the multi-information display lights up.
        Fig 2: Examples Of Malfunction Indicator Lights
        G01112744Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      • To check the Diagnostic Trouble Codes (DTC), connect the TOYOTA 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 3: Connecting Hand Held Tester To DLC3
        G01112745Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      • Freeze frame data:
    2. Freeze frame data records the battery condition when a malfunction is detected.
    3. When troubleshooting, this is useful for knowing the battery condition.
    3. 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.
  3. Check the DLC3:
    1. The HV control ECU conforms to ISO 14230 for communication.
    2. The terminal arrangement of the DLC3 complies with SAEJ1962 and matches the ISO 14230 format.
      Fig 4: Identifying DLC3 Connector Terminals
      G01112746Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 5: Identifying DLC3 Terminal Specifications
      G01112747Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. Inspect diagnosis:
    1. Check the auxiliary battery.
      1. Measure the voltage of the auxiliary battery.

        Voltage: 10 - 15 V  .

      2. Inspect the auxiliary battery, fuses, fusible links, wiring harness, connectors and ground.
    2. Check the master warning light.
        NOTE: If the master warning light does not come on, suspect a burnt fuse, burnt bulb, or open in wiring harness.
        Fig 6: Identifying Master Warning Light
        G01112748Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Turn the ignition switch ON and confirm that the master warning light comes on.
      2. When the "READY" light is ON, the master warning light should go off.
        Fig 7: Identifying Ready Light
        G01112749Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      If the lamp remains on, the diagnosis system has detected a malfunction or abnormality in the system.

    3. Check the DTC.
      1. Prepare a TOYOTA hand-held tester.
      2. Connect the TOYOTA hand-held tester to the DLC3.
      3. Turn the ignition switch ON and push the TOYOTA hand-held tester main switch ON.
      4. Use the TOYOTA hand-held tester to check the DTC and freeze frame data and note them down. (For operating instructions, see the TOYOTA hand-held tester operator's manual).
        1. Since the HV battery ECU stores DTC and freeze frame data, when troubleshooting, check all of the DTC, write down the freeze fame data and perform inspection according to the procedures of "Circuit Inspection".
        2. Because the HV battery ECU is communicating with the HV ECU, if any DTC is stored in the HV battery ECU, check and record DTC stored in the HV ECU. For tables of DTC's, see DIAGNOSTIC TROUBLE CODE CHART .
      5. See a related page to confirm details of the DTC.
        Fig 8: Connecting Hand Held Tester To DLC3
        G01112750Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Clear DTC after completion of repair.
      Fig 9: Connecting Hand Held Tester To DLC3
      G01112751Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        NOTE: Before clearing, check that DTC for the HV battery ECU, DTC for the ECU which is related with freeze frame data and the freeze frame data are recorded.
      1. Connect the TOYOTA hand-held tester to the DLC3.
      2. Operate the TOYOTA hand-held tester to erase the DTC. See the TOYOTA hand-held tester operator's manual.
  5. Check for intermittent problems:
      NOTE: In the simulation test, reproduce the condition at trouble occurrence based on the customer's comments and the freeze frame data recorded with the DTC.
    1. Perform a simulation test. See SYMPTOM SIMULATION .
    2. Check the connector and terminal. See page HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE .
    3. Handle the connector. See page HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE .
  6. TOYOTA Hand-held Tester Display Items
    Fig 10: Defining Toyota Hand Held Tester Displays
    G01112752Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
scientia non olet · About LEMON Manuals