Section 432 (Cruise Control System - Diagnostics): Pre-Check

WARNING: This page is about a different car, the 2005 Lexus GS 430 and 2005 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.

DIAGNOSIS SYSTEM

Check the indicator.
1. Turn the ignition switch to ON.
2. Check that the CRUISE MAIN indicator light comes on when the cruise control main switch is turned ON, and that the indicator light goes off when the main switch is turned OFF.
  
  Fig 1: Checking Cruise Main Indicator Light
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
HINT:

If the indicator check result is not normal, proceed to troubleshooting (See PROBLEM SYMPTOMS TABLE ) for the combination meter .

Check the DLC3.

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

Fig 2: Checking DLC3

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DLC3

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 - 14 V	Always

HINT:

If the display shows "UNABLE TO CONNECT TO VEHICLE" as connecting the LEXUS hand-held tester to the DLC3 and turn the ignition ON, there is a problem either on the vehicle or on the tool.

If communication is normal when connecting the LEXUS hand-held tester to another vehicle, inspect the DLC3 on the original vehicle.
If communication is still not possible when connecting the LEXUS hand-held tester to another vehicle, the problem is probably in the LEXUS hand-held tester itself. Consult the Service Department listed in the LEXUS hand-held tester's instruction manual in that case.

Check the DTC.
HINT:

If a malfunction occurs in the speed sensor or in the stop light switch, etc. during cruise control driving, the ECU actuates AUTO CANCEL of the cruise control and turns ON and OFF the CRUISE MAIN indicator light to inform the driver of a malfunction. At the same time, the malfunction is stored in memory as a diagnostic trouble code.

Fig 3: Checking DTC Blinking Pattern
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Output DTC using SST.
1. Turn the ignition switch to ON.
2. Using SST, connect terminals TC and CG of the DLC3.
  SST 09843-18040
  
  Fig 4: Connecting Terminals TC And CG
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Read the DTC on the CRUISE MAIN indicator light.

HINT:

If the DTC is not output, inspect the cruise main indicator light circuit and the diagnosis circuit (See CRUISE MAIN INDICATOR LIGHT CIRCUIT ).
As an example, the blinking patterns for codes; normal 52 are shown in Fig 5 .

Fig 5: Example Of Blinking Patterns For Codes; Normal 52
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

USING LEXUS HAND-HELD TESTER
1. Hook up the LEXUS hand-held tester to the DLC3.
  
  Fig 6: Hooking Up Hand-Held Tester To DLC3
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Monitor the ECU data by following the prompts on the tester screen.
HINT:

LEXUS hand-held tester has a "Snapshot" function which records the monitored data.

Please refer to the LEXUS hand-held tester operator's manual for further details.

DATA LIST

HINT:

According to the DATA LIST displayed by the LEXUS handheld tester, you can read the value of the switch, the sensor and so on without parts removal. Reading the DATA LIST as a first step of troubleshooting is one of the method to shorten the labor time.

Connect the LEXUS hand-held tester to the DLC3.
Turn the ignition switch to ON.

According to the display on tester, read the "DATA LIST".

DATA LIST

Item	Measurement Item / Display (Range)	Normal Condition	Diagnostic Note
VEHICLE SPD	Vehicle speed / min.: 0km/h (0mph), max.: 255km/h (158mph)	Actual vehicle speed	-
MEMORY SPD	Cruise control memorized speed / min.: 0km/h (0mph), max.: 255km/h(158mph)	Memorized speed: Cruise control activated	-
THROTTLE	Required throttle opening angle / min.: 0°, max.: 125°	Required throttle opening angle (0° - 84°): Cruise control activated	-
CCS READY S	Cruise control system standby condition (Sub CPU) / ON or OFF	ON <=> OFF: Change ON/OFF each time Main SW is pressed in.	"1"
CCS READY M	Cruise control system standby condition (Main CPU) / ON or OFF	ON <=> OFF: Change ON/OFF each time Main SW is pressed in.	"1"
CANCEL SW	CANCEL SW signal / ON or OFF	ON: CANCEL SW ON	-
CANCEL SW	CANCEL SW signal / ON or OFF	OFF:CANCEL SW OFF	-
SET/COAST SW	SET/COAST SW signal / ON or OFF	ON: SET/COAST SW ON	-
SET/COAST SW	SET/COAST SW signal / ON or OFF	OFF: SET/COAST SW OFF	-
RES/ACC SW	RES/ACC SW signal / ON or OFF	ON: RES/ ACC SW ON	-
RES/ACC SW	RES/ACC SW signal / ON or OFF	OFF: RES/ACC SW OFF	-
STP LIGHT SW2 M	Stop light SW signal (Main CPU) / ON or OFF	ON: Brake pedal depressed	-
STP LIGHT SW2 M	Stop light SW signal (Main CPU) / ON or OFF	OFF: Brake pedal released	-
STP LIGHT SW2 S	Stop light SW signal (Sub CPU) / ON or OFF	ON: Brake pedal depressed	-
STP LIGHT SW2 S	Stop light SW signal (Sub CPU) / ON or OFF	OFF: Brake pedal released	-
STP LIGHT SW1 S	Stop light SW signal (Sub CPU) / ON or OFF	ON: Brake pedal depressed	-
STP LIGHT SW1 S	Stop light SW signal (Sub CPU) / ON or OFF	OFF: Brake pedal released	-
SHIFT DPOS	PNP SW signal (D position) / ON or OFF	ON: Shift D position	-
SHIFT DPOS	PNP SW signal (D position) / ON or OFF	OFF: Except shift D position	-
CRUISE CTRL	Cruise control system active condition / ON or OFF	ON: Cruise control activated	-
CRUISE CTRL	Cruise control system active condition / ON or OFF	OFF: Cruise control inactivated	-
CCS INDICATOR M	Cruise indicator signal (Main CPU) /ON or OFF	ON: "CCS READY" ON	"2"
CCS INDICATOR M	Cruise indicator signal (Main CPU) /ON or OFF	OFF: "CCS READY" OFF	"2"
CCS INDICATORS	Cruise indicator signal (Sub CPU) /ON or OFF	ON: "CCS READY" ON	"2"
CCS INDICATORS	Cruise indicator signal (Sub CPU) /ON or OFF	OFF: "CCS READY" OFF	"2"
MAIN SW (SUB)	Main SW signal (Sub CPU) / ON or OFF	ON: Main SW ON (Pressed in)	"3"
MAIN SW (SUB)	Main SW signal (Sub CPU) / ON or OFF	OFF Main SW OFF (Pressed out)	"3"
MAIN SW (MAIN)	Main SW signal (Main CPU) / ON or OFF	ON: Main SW ON (Pressed in)	"3"
MAIN SW (MAIN)	Main SW signal (Main CPU) / ON or OFF	OFF: Main SW OFF (Pressed out)	"3"

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 -> Indicator or wire harness or ECM failure

DTC CLEARANCE
1. The following actions will erase the DTCs and freeze frame data.
  1. LEXUS Hand-Held Tester:
    Operating the LEXUS hand-held tester to erase the codes.
  2. Except LEXUS Hand-Held Tester:
    Disconnecting the battery terminals or EFI fuse for 60 seconds or more.
2. After completing repairs, the DTC retained in memory can be cleared by removing the ECU-B fuse for 60 seconds or more with the ignition switch to OFF.
3. Check that the normal code is displayed after connecting the fuse.
PROBLEM SYMPTOM CONFIRMATION (ROAD TEST)
1. Inspect the SET switch.
  1. Push the main switch button to ON.
  2. Drive at a desired speed (40 km/h (25 mph) or higher).
  3. Press the control switch to the SET/COAST.
  4. After releasing the switch, check that the vehicle cruises at the desired speed.
    
    Fig 7: Inspecting SET Switch
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Inspect the ACCEL switch.
  1. Push the main switch button to 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 turned to RES/ACC, and that the vehicle cruises at the set speed when the switch is released.
  4. Momentarily press the control switch upward in the RES/ACC and then immediately release it. Check that the vehicle speed increases by about 1.5 km/h (Tap-up function).
    
    Fig 8: Inspecting ACCEL Switch
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Inspect the COAST switch.
  1. Push the main switch button to 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 turned to SET/COAST, and the vehicle cruises at the set speed when the switch is released.
  4. Momentarily press the control switch is turned to SET/COAST, and then immediately release it. Check that the vehicle speed decreases by about 1.5 km/h (Tap-down function).
    
    Fig 9: Inspecting COAST Switch
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Inspect the CANCEL switch.
  1. Push the main switch button to 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.
    - Depress the brake pedal
    - Shift to except D position
    - Push the main switch OFF
    - Pull the cruise control switch to CANCEL
    Fig 10: Inspecting CANCEL Switch
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Inspect the RESUME switch.
1. Push the main switch button to 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.
  - Depress the brake pedal
  - Shift to except D position
  - Pull the cruise control switch to CANCEL
4. After the control switch is turned to RES/ACC at the driving speed of more than 40 km/h (25 mph), check that the vehicle restores the speed prior to the cancellation.
  
  Fig 11: Inspecting RESUME Switch
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INPUT SIGNAL CHECK (Using LEXUS hand-held tester)
1. Connect the LEXUS hand-held tester to the DLC3
2. Check the control switch (MAIN, CANCEL, SET/COAST, RES/ACC).
  
  Fig 12: Checking Input Signal
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002