LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2009 >> Matrix Base, Automatic >> Repair and Diagnosis >> Accessories & Equipment >> Warning Systems >> Tire Pressure Monitoring >> Tire Pressure Warning System >> DTC C2191/91: Vehicle Speed Signal Error (Test Mode DTC) >> Inspection Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Inspection Procedure

NOTE:
  • When replacing the tire pressure warning ECU, read the transmitter IDs stored in the old ECU using the Techstream and write them down before removal.
  • It is necessary to perform initialization (See INITIALIZATION ) after registration (See REGISTRATION ) of the transmitter IDs into the tire pressure warning ECU if the ECU has been replaced.
  1. READ VALUE USING TECHSTREAM (VEHICLE SPEED) 
    1. Turn the ignition switch off.
    2. Connect the Techstream to the DLC3.
    3. Turn the ignition switch to ON.
    4. Turn the Techstream on.
    5. Enter the following menus: Chassis / Tire Pressure Monitor / Data List.
    6. Check that the values indicated on the Techstream and on the combination meter are the same.

    Tire Pressure Monitor 

    DATA LIST REFERENCE

    Tester Display Measurement Item/Range Normal Condition Diagnostic Note
    Vehicle Speed Vehicle speed/
    min.: 0 km/h (0 mph)
    max.: 255 km/h (158 mph)    		 Almost same as actual vehicle speed Speed indicated on combination meter

    OK: 

    Vehicle speed indicated on the Techstream and on the combination meter are the same  .

    NG: Go to step   2 

    OK: USE SIMULATION METHOD TO CHECK  (See PROBLEM SYMPTOMS TABLE )

  2. INSPECT TIRE PRESSURE WARNING ECU (SPD SIGNAL) 
    1. Disconnect the E44 ECU connector.
    2. Jack up the vehicle.
    3. Move the lever to N.
    4. Turn the ignition switch to ON.
    5. Check the waveform of the ECU connector using an oscilloscope while turning the wheel slowly.

    OK 

    TESTER CONNECTION SPECIFIED CONDITION CHART

    Tester Connection Switch Condition Specified Condition
    E44-2 (SPD) - E44-9 (GND) Ignition switch ON Correct waveform appears as shown

    Tool Setting 

    TOOL SETTING REFERENCE

    Item Contents
    Tool Setting 5V/DIV., 20 ms/DIV.
    Vehicle Condition Driving wheels rotating slowly
    Fig 1: Identifying Terminals Of E44 ECU Connector And Waveform
    G06034808Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT:

    The wavelength becomes shorter as the vehicle speed increases.

    NG: Go to step   3 

    OK: REPLACE TIRE PRESSURE WARNING ECU  (See TIRE PRESSURE WARNING ECU )

  3. CHECK HARNESS AND CONNECTOR (ECU - COMBINATION METER) 
    1. Disconnect the E44 ECU connector.
    2. Disconnect the E55 meter connector.
    3. Measure the resistance according to the value (s) in the table below.

    Standard Resistance 

    TESTER CONNECTION SPECIFIED CONDITION CHART

    Tester Connection Condition Specified Condition
    E44-2 (SPD) - E55-36 (+S) Always Below 1 Ω
    E44-2 (SPD) - Body ground Always 10 kΩ or higher
    Fig 2: Identifying Terminals Of E44 ECU And E55 Meter Connectors
    G06034809Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE COMBINATION METER  (See COMBINATION METER )

scientia non olet · About LEMON Manuals