2003 LEXUS LS430 Ecm

Fig. 29: Identifying Blinking Pattern Of CRUISE Main Indicator Light
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
2.DESCRIPTION
a. The ECM controls the dynamic radar cruise control system of the vehicle. The data and DTCs
relating to the dynamic radar cruise control system can be read from the DLC3 of the vehicle. If
either DTC or CRUISE OK is not displayed in the multi-information display on the combination
meter when checking for DTCs, there may be a problem with the combination meter or the CAN
communication and multiplex communication system.
Use the hand-held tester to check and solve the problem.
3.CHECK THE DLC3
a. 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. 30: Identifying DLC3 Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
ECM CONNECTOR TERMINALS RESISTANCE SPECIFICATION
HINT:
If the displa
y shows "UNABLE TO CONNECT TO VEHICLE" when you have connected the hand-held
Symbols (Terminals No.)Terminal DescriptionConditionSpecified Condition
SIL(7) - SG(5)Bus "+" lineDuring transmissionPulse generation
CG(4) - Body groundChassis groundAlwaysBelow 1 ohms
SG(5) - Body groundSignal groundAlwaysBelow 1 ohms
BAT(16) - Body groundBattery positiveAlways11 to 14V
CANH(6) - CANL(14)HIGH-level CAN bus lineIG switch OFF54 to 67 ohms
CANH(6) - Battery positiveHIGH-level CAN bus lineIG switch OFF1 Mohms or higher
CANH(6) - CG(4)HIGH-level CAN bus lineIG switch OFF3 kohms or higher
CANL(14) - Battery positiveLOW-level CAN bus lineIG switch OFF1 Mohms or higher
CANL(14) - CG(4)LOW-level CAN bus lineIG switch OFF3 kohms or higher

Fig. 33: Connecting Hand-Held Tester To DLC3
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.Constant speed control mode and vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic radar cruise control is in operation, the system
clears the stored vehicle speed in the ECM and cancels the dynamic radar cruise control operation.
Fig. 34: Identifying CRUISE Main Indicator Light And Master Warning Light

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Fig. 35: Fail
-Safe Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
2.Only in the vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic radar cruise control is in operation, the system
clears the stored vehicle speed in the ECM and cancels the dynamic radar cruise control operation.
Fig. 36: Identifying CRUISE Main Indicator Light And Master Warning Light

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Fig. 37: Fail
-Safe Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
3.Only in the vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic radar cruise control is in operation, the system
maintains the stored vehicle speed in the ECM and cancels the d
ynamic radar cruise control operation.

Fig. 38: Identifying CRUISE Main Indicator Light And Master Warning Light
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Fig. 39: Fail
-Safe Chart (1 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
4.Constant speed control mode and vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic radar cruise control is in operation, the system
clears the stored vehicle speed and cancels the dynamic radar cruise control operation.
HINT:
In the vehicle-to-vehicle distance control mode, the stored vehicle speed in the ECM is maintained.
Fig. 40: Fail
-Safe Chart (2 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1.DATA LIST
HINT:
From the DATA LIST displayed on the hand-held tester, the value of components such as the switch,
sensor, and actuator can be read without parts removal. Reading the DATA LIST as the first step of
troubleshooting is one way to shorten labor time.
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. According to the display on the tester, read the "DATA LIST".
CC (ECM):

Fig. 41: Data List Chart - CC (ECM) (1 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Fig. 42: Data List Chart - CC (ECM) (2 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
MULTI-INFORMATION DISPLAY CONTROL SWITCH (STEERING PAD SWITCH
MODULATOR):
DATA LIST (MULTI-INFORMATION DISPLAY CONTROL SWITCH (STEERING PAD
SWITCH MODULATOR))
2.ACTIVE TEST
HINT:
Performing the ACTIVE TEST using the hand-held tester allows components such as the relay, VSV, and
actuator to operate without parts removal. Performing the ACTIVE TEST as the first step of
troubleshooting is one way to shorten labor time.
It is possible to displa
y the DATA LIST during the ACTIVE TEST.
Item
Measurement Item / Display
(Range)
Normal ConditionDiagnostic Note
MULTI DSP2
SWSteering pad switch (DISP2)
signal / ON or OFFON <=> OFF: Change ON/OFF
each time steering pad switch
(DISP2) SW is pushed.-