dlc3 LEXUS LS430 2003 Factory Service Manual

By operating each of the A/C control switches as shown in the diagram below, it is possible to enter the
diagnostic check mode.
Fig. 11: Operation Methods Chart

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2.CHECK DLC3
a. The vehicle's ECM uses CAN and the to ISO 9141-2 for communication protocol. The terminal
arrangement of the DLC3 complies with SAE J1962 and meets the ISO 9141-2 format.

Fig. 12: Identifying DLC3 Terminals
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DLC3 TERMINALS SPECIFIED CONDITION
HINT:
If the display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the
hand-held tester to the DLC3, turned the ignition switch ON and operated the tester, there is a problem on
the vehicle side or tool side.
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 14 V
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

If the communication is normal when the tool is connected to another vehicle, inspect the DLC3 on
the original vehicle.
If the communication is still impossible when the tool is connected to another vehicle, the problem
is probably in the tool itself, so consult the Service Department listed in the tool's instruction
manual.
1.INDICATOR CHECK
a. Turn the ignition switch to the ON position while pressing the A/C control AUTO switch and R/F
(Recirculation/Fresh) switch simultaneously.
Fig. 13: Identifying Auto Switch (W/O LEXUS Navigation System)

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b. Check that the all indicators come on and go off 4 times in succession at 1 second intervals.
HINT:
After the indicator check is completed, the system enters the DTC mode automatically.
Press the "OFF" switch to cancel the indicator mode.

Fig. 15: Blinking Pattern Indictor Light
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2.DTC CHECK USING HAND-HELD TESTER
a. Connect the hand-held tester to the DLC3.
b. Read the DTC following the prompts on the tester screen. Please refer to the hand-held tester
operator's manual for further details.
c. Clear the DTCs.
HINT:
After repairing the malfunctions, clear the DTC.
1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch to the ON position.
3. Erase the DTCs followin
g the prompts on the tester screen.

Fig. 16: Connecting Hand-Held Tester To DLC3
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HINT:
Refer to the intelligent tester II operator's manual for further details.
1.ACTUATOR CHECK
a. Turn the ignition switch to the ON position while pressing the A/C control AUTO switch and R/F
(Recirculation / Fresh) switch simultaneously.
b. Press the R/F (Recirculation / Fresh) switch.
c. As each damper, motor and relay automatically operate the actuator check at 1 second intervals
from STEP No. 1 to No. 10 continuousl
y, check the temperature and air flow visually and by hand.

Fig. 21: Display Code - Conditions Chart
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1.DATA LIST
HINT:
From the DATA LIST displayed on the hand-held tester, you can read the values of the displays, sensors,
actuators and so on 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. From the display on the tester, select the "DATA LIST".
DATA LIST / AIR CONDITIONER:
DATA LIST / AIR CONDITIONER
ItemMeasurement Item / Display
(Range)Normal ConditionDiagnostic
Note

DATA LIST / ENGINE AND ECT / ALL:
DATA LIST / ENGINE AND ECT / ALL
2.ACTIVE TEST
HINT:
Performing the ACTIVE TEST
using the hand-held tester allows the relays, VSV, actuators and so on 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 display the DATA LIST on the hand-held tester during the ACTIVE TEST.
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. From the display on tester, perform the "ACTIVE TEST
".
ACTIVE TEST / AIR CONDITIONER:
ACTIVE TEST / AIR CONDITIONER
FOOT AIR
LEAKFoot air leak / ON, OFFCustomized value will be displayed-
DESTINATION
Destination / DOMEST, USA,
EUROPE, AUSTRAL,
MIDEAST, NO INFO
Changes with destinations-
REAR SOLAR
SENSRear solar sensor / min.: 0 max.:
255Changes depending on brightness-
NOX GAS SENSEmission gas Nox sensor / min.: 0
max.: 255Increases as the gas amount increases-
ItemMeasurement Item / Display
(Range)Normal ConditionDiagnostic
Note
REG PRESS
SENSRegulator pressure sensor / min.:
0 max.: 255Actual regulator pressure is displayed-
FILTER FLOW
VOLFilter flow volume / min.: 0 max.:
65535Actual filter flow volume is displayed-
REG CTRL
CURRNTRegulator control current / min.: 0
A max.: 255 A--
HUMIDITY
SENSHumidity sensor / min.: 0% max.:
100%Actual room humidity is displayed-
#CODESNumber of Trouble Codes / min.:
0 max.: 255Number of DTCs will be displayed-
ItemMeasurement Item/Display (Range)Normal ConditionDiagnostic Note
A/C SIGA/C signal/ ON or OFFA/C ON: ON-

Fig. 36: Room Temperature Sensor Circuit
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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 push the hand-held tester main switch on.
c. Select the item below in the DATA LIST, and read the display on the hand-held tester.
DATA LIST / AIR CONDITIONER:
DATA LIST / AIR CONDITIONER
OK:
The display is as specified in the normal condition.
Result:
ItemMeasure Item/Display (Range)Normal ConditionDiagnostic
Note
ROOM
TEMPRoom temperature sensor / min.: -6.5°C (20.3°F)
max.: 57.25°C (126.95°F)Actual room temperature
is displayed-

Fig. 42: Ambient Temperature Sensor Circuit
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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 push the hand-held tester main switch on.
c. Select the item below in the DATA LIST, and read the display on the hand-held tester.
DATA LIST / AIR CONDITIONER:
DATA LIST / AIR CONDITIONER:
OK:
The display is as specified in the normal condition.
ItemMeasurement Item/Display (Range)Normal ConditionDiagnostic
Note
AMBI TEMP
SENSAmbient temperature sensor / min.: -23.3°C (-
9.94°F) max.: 65.95°C (150.71 °F)Actual ambient
temperature is displayed-

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 push the hand-held tester main switch on.
c. Select the item below in the DATA LIST, and read the display on the hand-held tester.
DATA LIST / AIR CONDITIONER:
DATA LIST / AIR CONDITIONER
OK:
The display is as specified in the normal condition.
Result:
AIR CONDITIONER TEST RESULT
B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
C: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )
A: Go to next step
2.INSPECT AIR CONDITIONING AMPLIFIER (TE - SG)
a. Remove the A/C amplifier with connectors still connected.
b. Turn the ignition switch to the ON position.
c. Measure the voltage according to the value (s) in the table below.
Standard:
AIR CONDITIONING AMPLIFIER (TE - SG) VOLTAGE
HINT:
ItemMeasure Item/Display (Range)Normal ConditionDiagnostic
Note
EVAP
TEMPEvaporator temperature sensor / min.: -29.7°C (-
21.46°F) max.: 59.55°C (139.19°F)Actual evaporator
temperature is displayed-
NGA
OK (Checking from the PROBLEM SYMPTOM TABLE)B
OK (Checking from the DTC)C
Tester connectionConditionSpecified condition
A36-20 (TE) - A36-15 (SG-7)Ignition switch ON at 0°C (32°F)2.0 to 2.4 V
A36-20 (TE) - A36-15 (SG-7)Ignition switch ON at 15°C (59°F)1.4 to 1.8 V