Section 457 (Cruise Control System - Diagnostics): Pre-Check

WARNING: This page is about a different car, the 2005 Lexus RX 330. However, it is still accessible from the selected car via links, so may be relevant.

DIAGNOSIS SYSTEM

Description
ECM controls the function of the cruise control on a vehicle.

Data stored in the cruise control and on the DTC can be read from the DLC3 on the vehicle. If CRUISE MAIN indicator light does not come on after the DTC check, there is a malfunction of the cruise control. Use the hand-held tester or SST to check and solve the problem.

Check the DLC3.

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

Fig 1: Identifying DLC3 Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DLC3 CONNECTOR TERMINALS NO, CONNECTION CONDITION AND CONDITION DETAIL

Terminal No.	Connection/Specified Condition	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 ON, there is a problem either with the vehicle or with the tool.

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, the problem is probably in the tool itself. 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 comes on when the main switch button is ON, and that the indicator light goes off when the main switch is OFF.
  HINT:
  
  If there is a problem with the indicator, inspect the cruise main indicator light circuit (See CRUISE MAIN INDICATOR LIGHT CIRCUIT ).
  
  Fig 2: Identifying CRUISE MAIN Indicator Light
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  HINT:
  
  If a malfunction occurs in the vehicle speed sensors or stop lamp switch assy, etc. during cruise control driving, the ECM actuates AUTO CANCEL of the cruise control and then the CRUISE MAIN indicator light will start to blink, informing the driver of a malfunction. At the same time, data of the malfunction is stored as a diagnostic trouble code, or DTC.
  
  Fig 3: Identifying Blinking Pattern Of CRUISE MAIN Indicator Light
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DTC CHECK (USING SST CHECK WIRE)

Check DTCs using SST check wire.

SST 09843-18040

Using SST, connect terminals TC and CG of DLC3.
SST 09843-18040

Fig 4: Identifying DLC3 Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Turn the ignition switch to the ON position.

Read and record any DTCs from the CRUISE MAIN indicator light on the combination meter. Refer to the chart on the left for examples of a normal code and code 52.

HINT:

If the CRUISE MAIN indicator light does not blink any DTC codes or the normal code, inspect the warning light circuit.

SYSTEM NAME AND REFERENCE

System Name	Refer to
TC and CG terminal circuit	DIAGNOSIS CIRCUIT
CRUISE MAIN indicator light circuit	CRUISE MAIN INDICATOR LIGHT CIRCUIT

Fig 5: Identifying Blinking Pattern Of CRUISE MAIN Indicator Light (Normal Code And Code 52)

Refer to the DIAGNOSTIC TROUBLE CODE CHART for DTC information.
Clear the DTCs.
Remove the battery cable or ECU-IG fuse.

DTC CHECK (USING HAND-HELD TESTER)
1. Check DTCs using the hand-held tester.
  1. Connect the hand-held tester to DLC3.
  2. Turn the ignition switch to the ON position.
  3. Read the DTC on the tester screen.
2. Clear the DTCs using the hand-held tester.
  1. Connect the hand-held tester to DLC3.
  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
1. While the hand-held tester is connected to the DLC3 and with the ignition switch turned to the ON position, the CRUISE CONTROL data list can be displayed. Follow the prompts on the tester screen to access the data list.
  CC (ECM):
  
  Fig 6: Data List Chart (CC (ECM))
  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 cruise indicator not turn on -> CRUISE MAIN indicator or wire harness or ECM failure
PROBLEM SYMPTOM CONFIRMATION (ROAD TEST)
1. Inspect the SET switch.
  1. Push the main switch button ON.
  2. Drive at a desired speed (40 km/h (25 mph) or higher).
  3. Push down the control switch to the -/SET position.
  4. After releasing the switch, check that the vehicle cruises at the desired speed.
2. Inspect the '+' switch.
  1. Push the main switch button ON.
  2. Drive at a desired speed (40 km/h (25 mph) or higher).
  3. Check that the vehicle speed increases while the control switch is pushed up to +/RES, and that the vehicle cruises at the set speed when the switch is released.
  4. Momentarily push the control switch upward to the +/RES, and then immediately release it. Check that the vehicle speed increases by about 1.6 km/h (Tap-up function).
3. Inspect the '-' switch.
  1. Push the main switch button ON.
  2. Drive at a desired speed (40 km/h (25 mph) or higher).
  3. Check that the vehicle speed decreases while the control switch is pushed down to -/SET, and the vehicle cruises at the set speed when the switch is released.
  4. Momentarily push the control switch downward to -/SET, and then immediately release it. Check that the vehicle speed decreases by about 1.6 km/h (Tap-down function).
4. Inspect the CANCEL switch.
  1. Push the main switch button ON.
  2. Drive at a desired speed (40 km/h (25 mph) or higher).
  3. When operating one of the followings, check that the cruise control system is cancelled and that the normal driving mode is reset.
    - Depressing the brake pedal.
    - Shifting to any gear except D.
    - Pushing the main switch button OFF.
    - Pulling the control switch CANCEL.
5. Inspect the RES switch.
  1. Push the main switch button ON.
  2. Drive at a desired speed (40 km/h (25 mph) or higher).
  3. When operating one of the followings, check that the cruise control system is cancelled and that the normal driving mode is reset.
    - Depressing the brake pedal.
    - Shifting to any gear except D.
    - Pulling the control switch CANCEL.
  4. After the control switch is pressed towards +/RES at the driving speed of more than 40 km/h (25 mph), check that the vehicle resumes the same speed maintained before the cancellation.