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Cruise Control System - Diagnostics: Pre-Check

  1. DIAGNOSIS SYSTEM 
    1. Description

      The ECM stores trouble codes. The diagnosis system allows for reading of the trouble codes from the DLC3. If the CRUISE MAIN indicator light does not come on after DTC check, it means a malfunction has occurred in the cruise control system.

      Use the hand-held tester or SST to check and solve the problem.

    2. Check the DLC3.

      The ECM uses ISO 9141-2 for data communication. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

      Fig 1: Identifying DLC3 Terminals CG And TC
      G02937369Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TERMINAL AND SPECIFIC CONDITION

      Terminal No. Tester connection/Specification Condition
      4 Chassis Ground - Body Ground / 1 Ω or less Always
      7 Bus + Line / Pulse generation During Communication
      16 Battery Positive - Body Ground / 9 to 14 V Always

      HINT:

      If the display shows "UNABLE TO CONNECT TO VEHICLE" after connecting the hand-held tester to the DLC3 and turning the ignition to the ON position, there is a problem either with the vehicle or the tool. (Hand held tester ONLY)

      • If communication is normal when connecting the tool to another vehicle, inspect the DLC3 on the original vehicle.
      • If communication is still not possible when connecting the tool to another vehicle, it suggests the problem is the tool's own. In this case, consult the Service Department listed in the tool's instruction manual.
    3. Check the indicator.
    1. Turn the ignition switch to the ON position.
    2. Check that the CRUISE main indicator light comes on when the cruise control main switch ON-OFF button is pushed on, and that the indicator light goes off when the ON-OFF button is pushed off.

    HINT:

    If there is a problem with the indicator, inspect the CRUISE MAIN INDICATOR LIGHT CIRCUIT  .

    Fig 2: Locating Indicator Cruise Control Main Switch
    G02937370Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    Fig 3: Locating Cruise Main Indicator Light
    G02937371Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT:

    If a malfunction occurs in the vehicle speed sensor, stop lamp switch assy, or other related parts while cruise control driving, the ECM actuates AUTO CANCEL of the cruise control. Then the CRUISE main indicator light starts to blink, informing the driver of the malfunction. At the same time, data of the malfunction is stored as a diagnostic trouble code (DTC).

    Fig 4: Identifying Indicator Light Time Cycle
    G02937372Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. DTC CHECK USING SST CHECK WIRE 
    1. Check DTCs using SST check wire.
      1. Turn the ignition switch off.
      2. Using SST, short-circuit between terminals TC and CG of the DLC3.

        SST 09843-18040

      3. Turn the ignition switch to the ON position.
        Fig 5: Identifying DLC3 Terminals TC And CG
        G02937373Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      4. Read and record DTCs from the CRUISE main indicator light on the combination meter. As examples, refer to the chart on the left for the blinking of the normal code and trouble code 52.

      HINT:

      If the CRUISE main indicator light does not blink because of any DTC or in the normal code blinking pattern, inspect the following circuits.

      Fig 6: Identifying DLC3 Normal Code And Trouble Code Time Cycle Difference
      G02937374Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      DLC RELATIVE CIRCUIT

      Relevant circuit See
      TC and CG terminal circuit DLC3 CIRCUIT 
      CRUISE main indicator light circuit CRUISE MAIN INDICATOR LIGHT CIRCUIT 
    2. Clear the DTCs.
      1. Turn the ignition switch off.
      2. If DTCs are indicated, repair the relevant circuits referring to the DIAGNOSTIC TROUBLE CODE CHART  .
      3. Clear the DTCs according to either one of the following procedures.
      • Disconnect the negative (-) battery cable for at least 10 seconds, then reconnect it.
      • Remove the EFI fuse for at least 10 seconds, then reinstall it.
    3. Recheck DTCs (see step ( a)).
  3. DTC CHECK USING HAND-HELD TESTER 
    1. Check DTCs using the hand-held tester.
      1. Turn the ignition switch off.
      2. Connect the hand-held tester to the DLC3.
      3. Turn the ignition switch to the ON position.
      4. Read DTCs on the tester screen.
    2. Clear the DTCs using the hand-held tester.
    1. Turn the ignition switch off.
    2. Turn the ignition switch to the ON position.
    3. Clear the DTCs following the prompts on the tester screen.

    HINT:

    Hand-held tester has a "Snapshot" function which records the monitored data. Refer to the hand-held tester operator's manual for further details.

    Fig 7: Connecting DLC3 With Hand-Held Tester
    G02937375Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. DATA LIST 

    HINT:

    Following to the DATA LIST displayed by the hand-held tester, you can read the values of the switches, sensors, actuators and so on without parts removal. Reading the DATA LIST as the first step of troubleshooting is one of the methods to shorten labor time.

    1. Connect the hand-held tester to the DLC3.
    2. Turn the ignition switch to the ON position.
    3. According to the display on the tester, read the "DATA LIST".
    Fig 8: Item Range And Normal Condition Data List
    G02937376Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT:

    "3" is OK but "1" is NG --> ECM failure

    "1" is OK but "2" is NG --> DTC output or ECM failure

    "3" is OK but the cruise indicator does not come on --> CRUISE main indicator, wire harness or ECM failure

  5. PROBLEM SYMPTOM CONFIRMATION (ROAD TEST) 
    1. Inspect the SET function.
      1. Push the ON-OFF button on.
      2. Drive at the required speed (40 km/h (25 mph) or higher).
      3. Push down the cruise control main switch to "SET/-".
      4. After releasing the switch, check that the vehicle cruises at the set speed.
      Fig 9: Inspecting SET Function
      G02937377Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Inspect the '+' (ACCEL) function.
      1. Push the ON-OFF button on.
      2. Drive at the required speed (40 km/h (25 mph) or higher).
      3. Push down the cruise control main switch to "SET/-".
      4. Check that vehicle speed increases while the cruise control main switch is pushed up to "RES/+", and that the vehicle cruises at the newly set speed when the switch is released.
      5. Momentarily (approximately 0.6 second) push up the cruise control main switch to "RES/+" and then immediately release it. Check that vehicle speed increases by approximately 1.6 km/h (1.0 mph) (Tap-up function).
      Fig 10: Inspecting '+' (ACCEL) Function
      G02937378Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Inspect the '-' (COAST) function.
      1. Push the ON-OFF button on.
      2. Drive at the required speed (40 km/h (25 mph) or higher).
      3. Push down the cruise control main switch to "SET/-".
      4. Check that vehicle speed decreases while the cruise control main switch is pushed down to "SET/-", and that the vehicle cruises at the newly set speed when the switch is released.
      5. Momentarily (approximately 0.6 second) push down the cruise control main switch to "SET/-" and then immediately release it. Check that vehicle speed decreases by approximately 1.6 km/h (1.0 mph) (Tap-up function).
      Fig 11: Inspecting '-' (COAST) Function
      G02937379Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Inspect the CANCEL function.
      1. Push the ON-OFF button on.
      2. Drive at the required speed (40 km/h (25 mph) or higher).
      3. Push down the cruise control main switch to "SET/-".
      4. When doing one of the following, check that the cruise control system is cancelled and that the normal driving mode is reset.
      • Depressing the brake pedal
      • D position circuit in the park/neutral position switch ON --> OFF (Shifting into any position except D while driving)
      • Pushing the ON-OFF button off
      • Pulling the cruise control main switch to CANCEL

      HINT:

      Cruise control will be halted if VSC starts operation while driving.

      Fig 12: Inspecting CANCEL Function
      G02937380Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    5. Inspect the RES (RESUME) function.
    1. Push the ON-OFF button on.
    2. Drive at the required speed (40 km/h (25 mph) or higher).
    3. Push down the cruise control main switch to "SET/-".
    4. When doing one of the following, check that the cruise control system is cancelled and that the normal driving mode is reset.
      • Depressing the brake pedal
      • D position circuit in the park/neutral position switch ON --> OFF (Shifting into any position except D while driving)
      • Pulling the cruise control main switch to CANCEL

      HINT:

      Cruise control will be halted if VSC starts operation while driving.

      Fig 13: Inspecting RES (RESUME) Function
      G02937381Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    5. After pushing the cruise control main switch to "RES/+" at a driving speed of more than 40 km/h (25 mph), check that the vehicle restores the speed prior to the cancellation.
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