2003 LEXUS LS430 check engine

Torque: 5.5 N.m (55 kgf.cm, 48 in..lbf)
8.INSTALL ECM COVER
a. Install the ECM cover with the 3 bolts.
Torque: 5.0 N.m (51 kgf.cm, 44 in..lbf)
9.INSTALL ENGINE ROOM SIDE COVER
a. Install the engine room side cover with the 3 clips.
10.CONNECT BATTERY NEGATIVE TERMINAL
11.CONFIGURE ECM FOR OPTIONAL DYNAMIC RADAR/LASER CRUISE CONTROL
a. Be sure to perform the following procedures after replacing the ECM.
1. Turn the ignition switch ON.
2. Turn the cruise main switch ON.
3. With the brake pedal depressed, set the cruise control main switch to RES/ACC 3 times within 3
seconds. Check that the VSC buzzer sounds at this time.
4. Turn the ignition switch OFF.
5. Connect the intelligent tester II to the DLC3.
6. Turn the ignition switch ON and push the intelligent tester II main switch ON.
7. Select the item "L/C Option Flag" in the Data List.
8. Check that YES is displayed.
12.POWER WINDOW CONTROL SYSTEM INITIALIZE (See INITIALIZATION
)
13.FRONT POWER SEAT CONTROL SYSTEM INITIALIZE (See INITIALIZATION
)
REPLACEMENT
1.REMOVE ACCELERATOR PEDAL ROD ASSY

3.SYSTEM FUNCTION
When the steering lock ECU detects that the unlock warning switch is ON, the ECU provides current to
the transponder key coil and produces a faint electric wave. A transponder chip in the key and receives
the faint electric wave. Upon receiving the faint electric wave, the transponder chip outputs a key ID code
signal. The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then
the signal is transmitted to the ECU.
The ECU matches the key's ID code with the vehicle's ID code, which was previously registered in the
ECU and then communicates the results to the ECM using SFI communication.
After the identification results show that the key's ID code matches the vehicle's ID code and the ECU has
confirmed their match: 1) the immobilizer system does not immobilize the engine and the engine starting
controls (fuel injection control and ignition control) enter standby mode; and 2) the ECU transmits a
security indicator signal that communicates "indicator off" to the theft warning ECU (theft deterrent
ECU). Then, the theft warning ECU turns off the security indicator lamp.
HINT:
Use this procedure to troubleshoot the engine immobilizer system.
The hand-held tester should be used in steps 4, 5 and 7.
1.VEHICLE BROUGHT TO WORKSHOP
2.CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK (See CUSTOMER
PROBLEM ANALYSIS CHECK )
3.CRANK ENGINE FOR MORE THAN 10 SECONDS
4.CHECK FOR DTCS
a. Check for DTCs and note any codes that are output.
b. Delete the DTC.
c. Recheck for DTCs. Based on the DTC output in (a), try to force output of the same SFI system
DTC or engine immobilizer system DTC by simulating the operation indicated by the DTC.
1. If the DTC does not reoccur, proceed to A.
2. If the SFI system DTC reoccurs, proceed to B.
3. If the engine immobilizer system DTC reoccurs, proceed to C.
B: Go to SFI SYSTEM (See HOW TO PROCEED WITH TROUBLESHOOTING
)
C: Go to step 8
illuminates or starts blinking.

a. Register the ECU communication ID.
1. Using SST, connect terminals TC and CG of the DLC3.
SST 09843-18040
Fig. 9: Connecting Terminals TC And CG Of DLC3 Using SST

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2. Turn the ignition switch ON (do not start the engine) and leave it as is for 30 minutes.
3. Turn the ignition switch OFF and disconnect terminals TC and CG.
4. Check that the engine starts.
Fig. 10: Problem Symptoms Table
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1.CHECK TRANSPONDER KEY AMPLIFIER

Fig. 33: Checking Wire Harness (Steering Lock ECU -Unlock Warning Switch Assy)
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NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: REPLACE STEERING LOCK ECU
CIRCUIT DESCRIPTION
This DTC is output when: 1) during the key code registration, a key malfunction occurs; or 2) the key code was
unable to be registered properly. Follow the inspection procedure below.
TRANSPONDER CHIP MALFUNCTION DTC REFERENCE TABLE
INSPECTION PROCEDURE
1.RE-REGISTER KEY
a. Delete the DTC (See DTC CHECK/CLEAR
).
b. Re-register the key (See REGISTRATION
), and check that the engine starts with the key.
OK: Engine starts.
NG: REPLACE KEY
OK: NORMAL (INSPECTION FINISHED)
CIRCUIT DESCRIPTION
This DTC is output when a key with an incomplete key code is inserted into the ignition key cylinder.
UNMATCHED ENCRYPTION CODE DTC REFERENCE TABLE
INSPECTION PROCEDURE
REPLACE KEY
DTC No.DTC Detection ConditionTrouble Area
B2793Transponder chip malfunctionSmart key
DTC No.DTC Detection ConditionTrouble Area
B2794Key with incomplete key code is
insertedSmart key

CIRCUIT DESCRIPTION
This DTC is output when a key with a key code that has not been registered in the ECU is inserted into the
ignition key cylinder.
UNMATCHED KEY CODE DTC REFERENCE TABLE
INSPECTION PROCEDURE
1.DELETE DTC AND INSERT ALL PRESENTLY AVAILABLE KEYS TO CHECK WHETHER
ENGINE STARTS OR NOT
OK: Engine starts.
NG: REPLACE KEY THAT CANNOT START ENGINE
OK: NO PROBLEM (BECAUSE OF KEY RE-REGISTRATION)
CIRCUIT DESCRIPTION
This DTC is output when a key that does not have a transponder chip is inserted into the ignition key cylinder or
if communication between the key and steering lock ECU is not possible.
Fig. 34: Communication Malfunction Circuit Description

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WIRING DIAGRAM
DTC No.DTC Detection ConditionTrouble Area
B2795Key with unregistered key code is
insertedSmart key

Fig. 35: No Communication In Immobilizer System, DTC B2798: Communication Malfunction No. 2
DTC - Wiring Diagram
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INSPECTION PROCEDURE
1.READ DATA LIST USING HAND-HELD TESTER
a. Connect the hand-held tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
b. Turn the ignition switch ON with the key that cannot start the engine.
c. Read the DATA LIST.
Steering lock ECU:
DATA LIST - STEERING LOCK ECU
OK: "UNSET" (Ignition switch ON) appears on the screen.
NG: Go to step 2
OK: REPLACE STEERING LOCK ECU
2.CHECK WHETHER ENGINE STARTS WITH OTHER KEYS
a. Check if the en
gine starts with the vehicle's other keys.
Item
Measurement Item/
Display (Range)
Normal ConditionDiagnostic Note
IMMOBILIZERImmobilizer system
status/ SET or UNSETUNSET: Ignition switch
ON SET: Without key-

OK: Engine starts.
NG: Go to step 3
OK: RE-REGISTER OR REPLACE KEY THAT CANNOT START ENGINE
3.CHECK WIRE HARNESS (STEERING LOCK ECU - TRANSPONDER KEY AMPLIFIER)
a. Disconnect the S46 ECU connector.
b. Disconnect the T8 amplifier connector.
c. Measure the resistance of the wire harness side connectors.
Standard:
STEERING LOCK ECU - TRANSPONDER KEY AMPLIFIER - RESISTANCE TABLE
Tester connectionSpecified condition
S46-7 (VC5) - T8-1 (VC5)Below 1 ohms
S46-17 (CODE) - T8-4 (CODE)Below 1 ohms
S46-8 (RXCK) - T8-3 (RXCK)Below 1 ohms
S46-16 (TXCT) - T8-1 (TXCT)Below 1 ohms
S46-7 (VC5) or T8-1 (VC5) - Body ground10 kohms or higher
S46-17 (CODE) or T8-4 (CODE) - Body ground10 kohms or higher
S46-8 (RXCK) or T8-3 (RXCK) - Body ground10 kohms or higher
S46-16 (TXCT) or T8-5 (TXCT) - Body ground10 kohms or higher

Fig. 36: Checking Wire Harness (Steering Lock ECU -Transponder Key Amplifier)
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NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
4.REPLACE TRANSPONDER KEY AMPLIFIER
a. After replacing the transponder key amplifier with a normally functioning amplifier, check that the
engine starts.
OK: Engine starts.
NG: REPLACE STEERING LOCK ECU
OK: END
CIRCUIT DESCRIPTION
This DTC is output when a communication error occurs between the transponder key amplifier and steering
lock ECU. Some possible reasons for the communication error are: 1) 2 or more smart keys are positioned too
close together, or 2) noise is occurring in the communication line. Follow the inspection procedure below.
Fig. 37: Communication Malfunction No. 1 Circuit Description

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WIRING DIAGRAM