2003 LEXUS LS430 ignition

Fig. 114: DTC C1774 Detecting Condition And Trouble Area
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WIRING DIAGRAM
Fig. 115: Power Source Wiring Diagram

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INSPECTION PROCEDURE
1.INSPECT SUSPENSION CONTROL ECU
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position and turn the hand-held tester main switch on.
c. Select the item below in the DATA LIST and read its value displa
yed on the hand-held tester.

Fig. 118: Tester Connection Specified Condition Description Table
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OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
5.INSPECT SUSPENSION CONTROL ECU
a. Remove the suspension control ECU with connectors connected.
b. Turn the ignition switch to the ON position.
c. Measure the voltage according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION
NG: Go to step 6
Tester ConnectionSpecified Condition
A20-1 (B) - A20-4 (GND)10 to 14 V

Fig. 121: DTC C1776 Detecting Condition And Trouble Area
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WIRING DIAGRAM
Fig. 122: Speed Sensor Wiring Diagram

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INSPECTION PROCEDURE
1.READ VALUE ON HAND-HELD TESTER
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position and turn the hand-held tester main switch on.
c. Select the item below in the DATA LIST and read its value displayed on the hand-held tester.
NORMAL CONDITION AIRSUS
d. Check that there is no difference between the speed value output from the speed sensor displayed
on the hand-held tester and the speed value displayed on the speedometer when driving the vehicle.
OK:
There is almost no difference in the displayed speed values.
ItemNormal Condition
WHEEL SPD FRActual vehicle speed

b. Turn the ignition switch to the ON position and turn the hand-held tester main switch on.
c. Select the item below in the DATA LIST and read its value displayed on the hand-held tester.
AIR SUS:
Fig. 125: Data List Value Description

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d. Check that the steering wheel turning angle value of the steering angle position sensor displayed on
the hand-held tester changes when turning the steering wheel.
Standard:
Steering wheel turning angle value changes.
NG: Go to step 2
OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
2.CHECK DIAGNOSTIC CODE OUTPUT
a. Check if the normal system code is output in the CAN communication system (SEE
SUSPENSION CONTROL ECU COMMUNICATION STOP MODE
).
OK:
No DTC is output in the CAN communication system.
NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE
OK:Go to next step
3.CHECK HARNESS AND CONNECTOR (STEERING SENSOR POWER SOURCE)
a. Disconnect the steering sensor S16 connector.
b. Turn the ignition switch to the ON position.
c. Measure the voltage according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Tester ConnectionSpecified Condition
S16-1 (IG1) - S16-2 (ESS)10 to 14 V
S16-3 (BAT) - S16-2 (ESS)10 to 14 V

Fig. 127: DTC C1786 Detecting Condition And Trouble Area
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HINT:
DTC C1786 is output only in the test mode.
WIRING DIAGRAM
Fig. 128: Height Control Switch Wiring Diagram

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INSPECTION PROCEDURE
1.READ VALUE ON HAND-HELD TESTER
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position and turn the hand-held tester main switch on.
c. Select the item below in the DATA LIST and read its value displayed on the hand-held tester.
AIRSUS:

Fig. 148: TD Terminal Wiring Diagram
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INSPECTION PROCEDURE
1.INSPECT DLC3 TERMINAL VOLTAGE (OPB TERMINAL)
a. Turn the ignition switch to the ON position.
b. Measure the voltage according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Tester ConnectionSpecified Condition
D1-11 (OPB) - D1-4 (CG)10 to 14 V
D1-4 (CG) - Body groundBelow 1 ohms

Fig. 3: Identifying Component Locations (3 Of 3)
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REPLACEMENT
HINT:
See COMPONENTS
See LOCATION
Installation is in the reverse order of removal.
Set to "SHIP" mode to prevent mechanical damage due to any impacts when the radio is transported.
Attach the label shown below to the top of the product case so as not to skip any procedure and to follow
the procedure correctly.
1.SHIP MODE SETTING
a. Take out all CDs.
b. Turn the ignition switch to the OFF position.
c. While holdin
g the "UP" and "DISC" switches, turn the ignition switch to the ACC position.

HINT:
The CD indicator light blinks during the mode setting and remains lit after the setting is
completed.
w/o Multi-display:
When the mode setting is completed, "SHIP" appears on the display.
d. Turn the ignition switch to the OFF position and disconnect the battery negative terminal.
Fig. 4: Identifying Radio Receiver Assy (W/O Multi
-Display)
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