check engine LEXUS LS430 2003 Factory Workshop Manual

a. This system uses ultrasonic sensors to detect any obstacles at the corners, the front or the rear of the
vehicle. The system then informs the driver of the distance between the sensors and the obstacles,
as well as their positions by displaying them on the multi-information display in the combination
meter and by sounding a buzzer. This information also appears on the multi-display on the models
equipped with a LEXUS navigation system.
2.FUNCTIONS OF COMPONENTS
FUNCTIONS OF COMPONENTS
3.OPERATION EXPLANATION
a. The clearance warning ECU assy determines whether the clearance sonar system should be
operated or not based on the clearance sonar main switch, the shift position, the vehicle speed and
the engine speed signals.
b. When the system operates, the clearance warning ECU transmits ultrasonic waves from the
ultrasonic sensor. If these waves encounter an obstacle within the sensor's range, the waves are
reflected back to the sensor, which transmits them to the clearance warning ECU assy.
Based on this information, the clearance warning ECU assy sends signals to the multi-information
display, the multi-display and the clearance warning buzzer. The appropriate distance between the vehicle
and the obstacle is then displayed, and the buzzer sounds.
HINT:
Refer to "OPERATION CHECK
" for detailed operation .
ComponentsFunction
Ultrasonic Sensor
Ultrasonic sensor consists of a sensor portion that transmits and receives
ultrasonic waves and a pre-amplifier that amplifies them. The ultrasonic
sensor outputs the ultrasonic transmission and reception signals to the
clearance warning ECU assy.
Clearance Sonar Main
SwitchTurns the clearance sonar system on and off.
Buzzer (No.1 & No.2)Emits an intermittent sound to inform the driver that the ECU has detected
an obstacle within a prescribed range.
Clearance Warning ECU
AssyJudges the approximate distance between the vehicle and the obstacle based
on the signals from the ultrasonic sensors and sends the display signal to the
display panel and buzzer signal to the buzzer.
Gateway ECU
Sends the display signal of the clearance warning ECU assy to the
combination meter and the multi-display. The signal for the multi-display is
output by converting it to an AVC-LAN signal.
Combination Meter (Multi-
information Display) &
Multi-displayDisplays the location of the obstacle and the approximate distance between
the vehicle and the obstacle. On the multi-display, the sound volume, buzzer
sounding distance, and sensor operating condition can be set on the setup
screen for this system.

Fig. 8: Identifying Clearance Sonar Display
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
2.INITIAL CHECK FUNCTION CHECK
a. Turn the ignition switch to the ON position.
b. Drive the engine at 2,500 RPM or less with the shift lever in any position except N, or at 1,500
RPM or less with the shift lever in the N position.

Fig. 26: Identifying Terminals Of ECU (Combination Meter Assy)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
COMBINATION METER ASSY CONNECTOR TERMINALS REFERENCE
Symbols
(Terminals No.)Wiring
ColorTerminal DescriptionConditionSpecified
Condition
IG + (C12-1) -
Body groundY - Body
groundIgnition switch signal
(ON)Ignition switch OFF -->
ONBelow 1 V --> 10
to 14 V
MPX + (C12-2) -
Body groundGR-B -
Body groundMultiplex
communication signal--
MPX- (C12-3) -
Body groundGR-B -
Body groundMultiplex
communication signal--
S (C12-4) - Body
groundB-Y - Body
groundTachometer signalEngine runningPulse generation
(See waveform 1)
CHECK (C12-5) -
Body groundY-R - Body
groundCHECK ENGINE
signalCHECK ENGINE warning
light ON --> OFFBelow 1 V --> 10
to 14 V
TEMS (C12-6) -
Body groundY - Body
groundTEMS SPORT signalTEMS SPORT indicator
light ON --> OFFBelow 1 V --> 10
to 14 V
A/B (C12-7) - V-R (W) - ODO/TRIP signalIgnition switch ON,
ODO/TRIP switch ON -->
Below 1 V --> 4.5

ECT PWR INDICIndicat. Lamp ECT PWR (OFF/ON)Confirm that the vehicle is stopped
and engine idling
Rr FOG INDICIndicat. Lamp Rr FOG (OFF/ON)Confirm that the vehicle is stopped
and engine idling
OIL LEVEL WARNIndicat. Lamp OIL LEVEL (OFF/ON)Confirm that the vehicle is stopped
and engine idling
Rr LIGHT INDICIndicat. Lamp Rr Light (OFF/ON)Confirm that the vehicle is stopped
and engine idling
VSC WARNIndicat. Lamp VSC (OFF/ON)Confirm that the vehicle is stopped
and engine idling
ARS WARNIndicat. Lamp ARS (OFF/ON)Confirm that the vehicle is stopped
and engine idling
MIL (ENGINE)Indicat. Lamp ENGINE (OFF/ON)Confirm that the vehicle is stopped
and engine idling
LOW WASHER
WARNIndicat. Lamp WASHER (OFF/ON)Confirm that the vehicle is stopped
and engine idling
ItemTest DetailsDiagnostic Note
SRS WARNIndicat. Lamp AIRBAG (OFF/ON)Confirm that the vehicle is stopped
and engine idling
HIGH BEAM INDICIndicat. Lamp BEAM (OFF/ON)Confirm that the vehicle is stopped
and engine idling
TURN INDIC-LIndicat. Lamp TURN L (OFF/ON)Confirm that the vehicle is stopped
and engine idling
TURN INDIC-RIndicat. Lamp TURN R (OFF/ON)Confirm that the vehicle is stopped
and engine idling
ABS WARNIndicat. Lamp ABS (OFF/ON)Confirm that the vehicle is stopped
and engine idling
TRC OFF INDICIndicat. Lamp TRAC (TRC) OFF
(OFF/ON)Confirm that the vehicle is stopped
and engine idling
SLIP INDICIndicat. Lamp SLIP (OFF/ON)Confirm that the vehicle is stopped
and engine idling
O/D OFF INDICIndicat. Lamp O/D OFF (OFF/ON)Confirm that the vehicle is stopped
and engine idling
ODO/TRIP DISPIndicat. ODO/TRIP DISPLAY (OFF/ON)Confirm that the vehicle is stopped
and engine idling
A/T OIL TEMPA/T OIL temperature operation (OFF/ON)Confirm that the vehicle is stopped
and engine idling
L-CRUISE DISPIndicat. Laser Cruise DISPLAY (OFF/ON)Confirm that the vehicle is stopped
and engine idling
L-CRS CHECK INDIndicat. Lamp L-CRUISE CHECK
(OFF/ON)Confirm that the vehicle is stopped
and engine idling
L-CRS READY INDIndicat. Lamp L-CRUISE READY
(OFF/ON)Confirm that the vehicle is stopped
and engine idling
Fr FOG INDICIndicat. Lamp Fr FOG (OFF/ON)Confirm that the vehicle is stopped

METER:
TACHO METER DATA LIST REFERENCE
OK:
Engine speed displayed on the tester is almost the same as the actual engine speed.
NG: Go to step 3
OK: REPLACE COMBINATION METER ASSY (SEE OVERHAUL
)
3.READ VALUE OF HAND-HELD TESTER (ENGINE SPEED SIGNAL)
a. Operate the hand-held tester according to the steps on the display and select the "DATA LIST".
ENGINE:
DATA LIST REFERENCE
OK:
Engine speed displayed on the tester is almost the same as the actual engine speed.
NG: GO TO ENGINE CONTROL SYSTEM (SEE REPLACEMENT
)
OK: GO TO NEXT STEP
4.INSPECT COMBINATION METER ASSY
INSPECTION USING OSCILLOSCOPE
a. Check the input signal waveform.
1. Remove the combination meter assy.
2. Connect the oscilloscope to the terminals C12-4 and body ground.
3. Start the engine.
4. Check the si
gnal waveform according to the condition (s) in the table below.
ItemMeasurement Item/ Range
(Display)Normal ConditionDiagnostic
Note
TACHO
METEREngine speed / Min.: 50 rpm,
Max.: 12,750 rpmAlmost same as actual engine speed
(When engine is running)-
ItemMeasurement Item/ Range
(Display)Normal ConditionDiagnostic
Note
ENGINE
SPDEngine speed / Min.: 50 rpm,
Max.: 12,750 rpmAlmost same as actual engine speed
(When engine is running)-

c. Check the deflection width of the speedometer indicator.
Reference: Below 0.5 km/h (0.3 mph)
2.INSPECT OUTPUT OF VEHICLE SPEED
a. Check the output signal waveform.
1. Remove the combination meter assy.
2. Connect the oscilloscope to terminal C12-19 and body ground.
3. Start the engine.
Fig. 87: Identifying Terminal C12
-19
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
4. Check the signal waveform according to the condition (s) in the table below.
SIGNAL WAVEFORM CONDITIONS
ItemCondition
Tool setting5 V/DIV, 20 ms/DIV

OK:
As shown in the illustration
HINT:
As vehicle speed increases, the cycle of the signal waveform narrows.
Fig. 88: Identifying Signal Waveform

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
3.INSPECT TACHOMETER
a. Check operation
b. Connect the tune-up test tachometer and start the engine.
Vehicle conditionDriving at approx. 20 Km/h (12 mph)

ON-VEHICLE INSPECTION
1.CHECK COOLING SYSTEM FOR LEAKS
a. Fill the radiator with coolant and attach a radiator cap tester.
Fig. 1: Checking Cooling System For Leaks

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
b. Warm up the engine.
c. Using a radiator cap tester, increase the pressure inside the radiator to 137 kPa (1.4 kgf/cm
2, 19.9

psi), and check that the pressure does not drop.
If the pressure drops, check the hoses, radiator and water pump for leaks. If no external leaks are found,
check the heater core, cylinder block and head.
2.CHECK ENGINE COOLANT LEVEL AT RESERVOIR
a. Check that the engine coolant level is between the LOW and FULL lines when the engine is cold.
If the engine coolant is low, check for leaks and add "TOYOTA Super Long Life Coolant" to the
FULL line.
If "TOYOTA Super Long Life Coolant" is not available, use a similar high quality ethylene glycol
based non-silicate, non-amino, non-nitrite and non-borate coolant with long-life hybrid organic acid
technology. Do not substitute plain water for engine coolant.
3.CHECK ENGINE COOLANT QUALITY
a. Remove the radiator cap.
b. Check if there are any excessive deposits of rust or scale around the radiator cap and radiator filler
hole, Also, the coolant should be free from oil.
HINT:
If excessively dirty, clean the coolant passage and replace the coolant.
c. Reinstall the radiator cap.
INSPECTION
1. INSPECT THERMOSTAT
HINT:
The thermostat is stamped with the valve openin
g temperature.

ON-VEHICLE INSPECTION
1.CHECK COOLING FAN SYSTEM
a. Look at the chart below. Check that when the cooling fan is in the condition on the left, its
operation is what is written on the right.
Standard when engine coolant temperature is below 82°C (180°F):
CONDITION AND OPERATION SPECIFICATION
If the fan does not operate as specified, proceed to next step.
2.INSPECT COOLING FAN MOTOR
a. Remove the air cleaner inlet No. 1.
b. Disconnect the 2 connectors.
c. Connect the battery and ammeter.
d. Check that the fan rotates smoothly, and then check the amperage on the ammeter.
Standard: 9.2 to 11.0 A at 20° C (68° F)
If the result is not as specified, replace the fan motor.
If the fan operates, proceed to the next step.
ConditionOperation (Fan Speed)
Ignition ON at engine stoppingNot rotating
A/C switch OFF at idle speedNot rotating
A/C switch ON at idle speedRotating (Low speed)
Disconnect ECT sensor connector at idle speedRotating (High speed)