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HOMESERVICE MANUALSTOYOTA2010TACOMA BASE, 4D PICKUP, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTWARNING SYSTEMSTIRE PRESSURE WARNING SYSTEM (DIAGNOSTIC CODES & CIRCUIT TESTS)TIRE PRESSURE WARNING SYSTEMDTC C2191/91: VEHICLE SPEED SIGNAL ERROR (TEST MODE DTC)PROCEDURE
2010 Toyota Tacoma Base, 4D Pickup, Standard

DTC C2191/91: Vehicle Speed Signal Error (Test Mode DTC): Procedure

2010 Toyota Tacoma Base, 4D Pickup, StandardSECTION Procedure
  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 ON and the Techstream on.
    4. Enter the following menus: Chassis / Tire Pressure Monitor / Data List /
    5. Check that the values indicated on the Techstream and on the combination meter are the same.
      TIRE PRESSURE MONITOR

      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 → See step   2 

    OK → See step   4 

  2. INSPECT TIRE PRESSURE WARNING ECU (SPD SIGNAL) 
    1. Disconnect the T14 ECU connector.
      Fig 1: Identifying T14 ECU Connector With Waveform Graph
      GTY203686Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Jack up the vehicle.
    3. Shift the lever to the neutral position.
    4. Check the waveform of the ECU connector using an oscilloscope, while turning any of the wheels slowly.
      MEASUREMENT CONDITION

      Item Contents
      Tool Setting 5 V/DIV., 20 ms/DIV.
      Vehicle Condition Any wheel is rotated slowly

      HINT: 

      The wavelength becomes shorter as the wheels are rotated faster.

      OK

      Tester Connection Switch Condition Specified Condition
      T14-2 (SPD) - T14-9 (GND) Ignition switch ON Correct waveform is as shown in Fig 1.

    NG → See step   3 

    OK → See step   5 

  3. CHECK HARNESS AND CONNECTOR (ECU - COMBINATION METER) 
    1. Disconnect the T14 ECU connector.
      Fig 2: Identifying C9 Meter And T14 ECU Connectors
      GTY179216Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the C9 meter connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      T14-2 (SPD) - C9-19 Always Below 1 Ω
      T14-2 (SPD) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   6 

  4. USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
  5. REPLACE TIRE PRESSURE WARNING ECU. Refer to  REMOVAL 
  6. GO TO METER / GAUGE SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING). Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.