Section 167 (Cruise Control System - Diagnosis): Pre-Check

WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.

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 Terminals CG & TC
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: Checking DLC3 Specifications Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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.
- Check the indicator.
  1. Turn the ignition switch to the ON position.
  2. Check that the CRUISE MAIN indicator light come, 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.
    
    Fig 3: Identifying Cruise Control Main Switch
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    Fig 4: Identifying Cruise Control Indicator Light
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  HINT:
  
  If there is a problem with the indicator, inspect the cruise main indicator light circuit (see CRUISE MAIN INDICATOR LIGHT CIRCUIT ).
  
  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. 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 5: Cruise Main Indicator Light Blinking Pattern
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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
    
    Fig 6: Short-Circuit Between Terminals TC & CG
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Turn the ignition switch to the ON position.
  4. Read and record DTCs from the CRUISE MAIN indicator light on the combination meter. As examples, refer to Fig 7 for the blinking of the normal code and trouble code 52.
  Fig 7: Inspecting Normal Code & Trouble Code 52 Blinking Pattern
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  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.
  
  For TC and CG terminal circuit, see DLC3 CIRCUIT .
  
  For CRUISE MAIN indicator light circuit, see 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 (see 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)).
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.
    
    Fig 8: Connecting Hand-Held Tester To DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  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.
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 g 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 9: DATA List Chart
  Courtesy 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
ROAD TEST
1. Inspect 'SET' function.
  
  Fig 10: Inspecting 'SET/COAST' Function
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. Push the ON-OFF button on.
  2. Drive at a desired speed of 40 km/h (25 mph) or higher.
  3. Push down the control switch lever to "SET/COAST".
  4. After releasing the lever, check that the vehicle cruises at the set speed.
2. Inspect 'ACC' function.
  
  Fig 11: Inspecting ACC Function
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. Set a desired speed as in procedure ( a).
  2. Check that vehicle speed increases while the control switch lever is pushed up to "RES/ACC".
  3. Check that the vehicle cruises at the newly set speed when the switch lever is released.
  4. Momentarily push up the control switch lever to "RES/ACC", and then release it. Check that vehicle speed increases approximately 1.6 km/h (1 mph) with each lever operation (Tap-up function).
3. Inspect 'COAST' function.
  1. Set a desired speed as in procedure ( a).
  2. Check that vehicle speed decreases while the control switch lever is pushed down to "SET/COAST".
  3. Check that the vehicle cruises at the newly set speed when the switch lever is released.
  4. Momentarily push down the control switch to "SET/COAST", and then release it. Check that vehicle speed decreases approximately 1.6 km/h (1 mph) with each lever operation (Tap-down function).
  HINT:
  
  Cruise control system automatically cancels when the vehicle speed goes below 40 km/h (25 mph).
4. Inspect 'CANCEL' function.
  
  Fig 13: Inspecting 'CANCEL' Function
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. Set a desired speed as in procedure ( a).
  2. Check that the system cancels cruise control while doing one of the following:
    - Depressing the brake pedal
    - Shifting into any position except D and 4 while driving
    - Pushing the cruise control main switch ON-OFF button off
    - Pulling the cruise control switch lever to "CANCEL"
5. Inspect 'RES' function.
  1. Set a desired speed as in procedure ( a).
    - After canceling the cruise control according to any of the above operations (other than turning the main switch ON-OFF button off), push up the switch lever to "RES/ACC" at a speed of 40 km/h (25 mph) or higher.
    - Check that the vehicle resumes the previously set speed.
  HINT:
  
  'RES' function does not resume the set speed when vehicle speed goes below 40 km/h (25 mph).