2003 LEXUS LS430 Ecm

Fig. 2: Identifying Engine Immobilizer System Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.ENGINE IMMOBILIZER SYSTEM DESCRIPTION
The engine immobilizer system is designed to prevent the vehicle from being stolen. This system uses a
transponder key ECU that stores the key codes of authorized ignition keys. If an attempt is made to start
the engine using an unauthorized key, the ECU sends a signal to the ECM to prohibit fuel delivery and
ignition, effectively disabling the engine.
2.FUNCTION OF MAIN COMPONENT
COMPONENT FUNCTION TABLE
3.SYSTEM FUNCTION
When the transponder key ECU detects that the unlock warning switch is ON, the ECU provides current
to the transponder ke
y coil and produces a faint electric wave. A transponder chip in the key grip and
ComponentOutline
Transponder key
coil/amplifierWhen key is inserted in ignition key cylinder, key coil receives key's code. Then
amplifier amplifies ID code and outputs it to transponder key ECU.
Unlock warning
switchDetects if key is in ignition key cylinder and outputs results to transponder key
ECU.
ECM
Through SFI communication, ECM receives ID verification results from
transponder key ECU. ECM also verifies ECUs. Then judgement of whether or not
to immobilize engine is made.
Security indicatorDepending on operation of theft warning ECU (theft deterrent ECU), interior
security indicator lamp illuminates or starts blinking.

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:
<00380056004800030057004b004c00560003005300550052004600480047005800550048000300570052000300570055005200580045004f00480056004b00520052005700030057004b0048000300480051004a004c005100480003004c00500050005200
45004c004f004c005d0048005500030056005c005600570048[m. 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 DIAGNOSTIC TROUBLE CODE CHART
)
C: Go to step 8
A: Go to next step
5.READ DATA LIST USING HAND-HELD TESTER
a. Connect the hand-held tester to the Controller Area Network Vehicle Interface Module (CAN
VIM). Then connect the CAN VIM to the DLC3.
b. Turn the ignition switch ON and push the hand-held tester main switch ON.
c. Read the DATA LIST.

a. When adding master keys and sub-keys (additional registration).
1. Register the key code (immobilizer code) in the transponder key ECU.
CODE REGISTRATION TABLE (ADDITIONAL REGISTRATION)
b. When replacing the transponder key ECU (new registration).
1. Register the key code (immobilizer code) in the transponder key ECU.
CODE REGISTRATION TABLE (IMMOBILIZER CODE)
2. Register the ECU COMMUNICATION ID between the ECM and the transponder key ECU.
CODE REGISTRATION TABLE (ECU COMMUNICATION ID)
c. When replacing the ECM.
1. Register the ECU COMMUNICATION ID between the ECM and the transponder key ECU.
CODE REGISTRATION TABLE (REPLACING ECM)
d. Erasure of key code.
1. Erase the key code.
CODE REGISTRATION TABLE (ERASING KEY CODE)
2.KEY REGISTRATION IN AUTOMATIC REGISTRATION (NEW REGISTRATION)
a. When an ignition key is inserted into the ignition key cylinder, the key code (immobilizer code)
registration is automatic. In this mode, a maximum of 4 key codes for 3 master keys and 1 sub-key
can be registered. Any order of registration for the master keys and sub-key is fine because the
transponder key ECU can distinguish between different types of keys.
HINT:
When a new transponder key ECU is installed, key codes (immobilizer codes) must be
Target ECUSee Step
Transponder key ECU3
Target ECUSee Step
Transponder key ECU2
Target ECUSee Step
ECM5
Target ECUSee Step
Transponder key ECU5
Target ECUSee Step
Transponder key ECU4

If the result is not as specified, there may be a malfunction on the wire harness side.
c. Reconnect the T9 ECU connector.
d. Measure the voltage of the connector.
Standard:
TRANSPONDER KEY ECU - VOLTAGE TABLE
If the result is not as specified, the ECU may have a malfunction.
e. Inspect using an oscilloscope.
Waveform 1 (Reference):
Body groundground
CPUB (T9-1) -
GND (T9-14)V-Y - W-BBatteryAlways10 to 14V
IG2 (T9-2) -
AGND (T9-13)B-VIgnition switchIgnition switch OFF -->
ON0V --> 10 to 14V
KSW (T9-3) -
AGND (T9-13)LG-B - VUnlock warning
switchNo key in ignition key
cylinder --> Key inserted10 kohms or higher --
> Below 1 ohms
Symbols
(Terminal No.)Wiring
ColorTerminal DescriptionConditionSpecified
Condition
KSW (T9-3) -
AGND (T9-13)LG-B - VUnlock warning switch
No key in ignition key
cylinder --> Key
inserted
10 to 14V 0V
VC5 (T9-9) -
AGND (T9-13)O - VPower sourceIgnition switch OFF --
> ON0 V --> 4.6 to
5.4V
TXCT (T9-12) -
AGND (T9-13)L-B - VTransponder key amplifier
communication signalIgnition switch OFF --
> ONPulse generation
(see waveform 1)
CODE (T9-10) -
AGND (T9-13)R-W - VTransponder key amplifier
communication signalIgnition switch OFF --
> ONPulse generation
(see waveform 2)
EFIO (T9-6) -
AGND (T9-13)B-Y - VECM output signalIgnition switch OFF --
> ONPulse generation
(see waveform 3)
EFII (T9-7) -
AGND (T9-13)GR-R - VECM input signalIgnition switch OFF --
> ONPulse generation
(see waveform 4)

Fig. 17: Identifying Waveform 4 Graph
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WAVEFORM 4 REFERENCE TABLE
3.CHECK ECM
TerminalEFII - GND
Tool Setting10 V/DIV., 500 ms/DIV.
ConditionIgnition switch OFF --> ON

Fig. 18: Identifying ECM Connectors
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
a. Disconnect the E2 and E4 ECM connectors.
b. Measure the voltage and resistance of the wire harness side connectors.
Standard:
ECM CONNECTORS - REFERENCE TABLE
If the result is not as specified, there may be a malfunction on the wire harness side.
c. Inspect using an oscilloscope.
Waveform 1 (Reference):
Symbols
(Terminal No.)Wiring
ColorTerminal
DescriptionConditionSpecified
Condition
IMI (E2-6) -
E01 (E4-2)GR-G - W-
BTransponder key
ECU input signalNo key in ignition key
cylinder --> Key insertedPulse generation
(see waveform 1)
IMO (E2-7) -
E01 (E4-2)GR-R - W-
BTransponder key
ECU output signalNo key in ignition key
cylinder --> Key insertedPulse generation
(see waveform 2)
E01 (E4-2) -
Body groundW-B - Body
groundGroundAlwaysBelow 1 ohms

Fig. 20: Identifying Waveform 2 Graph
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WAVEFORM 2 REFERENCE TABLE
1.DESCRIPTION
a. The ECM controls the vehicle's immobilizer system functions. Immobilizer system data and the
Diagnostic Trouble Codes (DTCs) can be read through the vehicle's Data Link Connector 3
(DLC3). In some cases, a malfunction may be occurring in the immobilizer system even though the
security indicator lamp is not illuminated. When the system seems to be malfunctioning, use the
hand-held tester to check for malfunctions and perform repairs.
2.CHECK DLC3
HINT:
TerminalIMO - GND
Tool Setting10 V/DIV., 500 ms/DIV.
ConditionNo key in ignition key cylinder --> Key inserted

Fig. 25: Transponder Key ECU DTC Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
2.ECM DTC CHART
Fig. 26: ECM DTC Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
CIRCUIT DESCRIPTION
This DTC will be output if the transponder key ECU does not detect that the unlock warning switch is ON even
when the ignition switch is ON. Under the normal conditions, the unlock warning switch is ON when the
i
gnition switch is ON.