Lexus RX300 (MCU15). Service manual — part 394

I08326

AUTO SW

R/F SW

AC2163

Blinking Pattern

4 times

1 sec.

1 sec.

ON

OFF

I08327

Trouble Code Display

I08326

A/C SW

A05185

DLC3

Hand–held Tester

DI–806

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

LEXUS RX300 (RM785E)

3.

INDICATOR CHECK

(a)

Turn the ignition switch on while pressing the A/C control
AUTO switch and R/F SW simultaneously.

(b)

Check that all the indicators light up and go off at 1 second
intervals 4 times in succession.

HINT:

S

After the indicator check is ended, the diagnostic trouble
code check begins automatically.

S

Press the OFF switch when desiring to cancel the check
mode.

4.

DTC CHECK (SENSOR CHECK)

(a)

Perform an indicator check. After the indicator check is
completed, the system enters the DTC check mode auto-
matically.

(b)

Read the DTC displayed on the panel. Refer to the list of
DTCs on page DI–809 when reading the DTCs.
(DTCs are out put at the temperature display.)
If the slower display is desired, press the Driver Side
Temp. Control Switch and change it to step operation.
Each time the Driver Side Temp. Control switch is
pressed, the display changes by 1 step.

5.

DTC CHECK USING HAND–HELD TESTER

(a)

Hook up the hand–held tester to the DLC3.

(b)

Read the diagnostic trouble codes by following the
prompts on the tester screen.
Please refer to the hand–held tester operator’s manual
for further details.

I08371

ECU–B

Engine Room J/B

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–807

LEXUS RX300 (RM785E)

6.

CLEARING DTC

(a)

Pull out the ECU–B fuse in Engine Room J/B for 10 sec.
or longer to clear diagnostic the DTC’s memory.

(b)

After reinserting the fuse, check that the normal code is
output.

I08326

R/F SW

I08326

A/C SW

Step No.

Display
code

Conditions

Blower
motor

Air flow
vent

Max. cool
damper

Air inlet
damper

Magnetic
clutch

Air mix
damper

1

2

3

4

5

6

7

8

9

10

0

1

3

2

4

5

6

7

8

9

0

1

17

31

FACE

OFF

FOOT*2

FOOT/DEF

DEF

FRESH

100% open

0% open

R/F

(RECIRC)

ON

Cool side
(–10% open)

Cool / Hot
(50% open)

Hot side
(110% open)

(54.5% open)

(52.0% open)

(31.0% open)

FOOT*1

DI–808

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

LEXUS RX300 (RM785E)

7.

ACTUATOR CHECK

(a)

After entering the sensor check mode, press the R/F
switch.

(b)

Since each damper, motor and relay automatically oper-
ates at 1 second intervals beginning in order from 20 in
the temperature display, check the temperature and air
flow visually and by hand.
If a slower display is desired, press the A/C switch and
change it to step operation. Each time the A/C switch is
pressed, the display changes by 1 step.

HINT:

S

Code are displayed in order from the smaller to the larger
numbers.

S

To cancel the check mode, press the Off switch.

*1: There is air flow from defroster.
*2: There is no air flow from defroster.

DI3FR–01

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–809

LEXUS RX300 (RM785E)

DIAGNOSTIC TROUBLE CODE CHART

If malfunction code is displayed during the DTC check, check the circuit listed for that code in the table below
(Proceed to the page given for that circuit.)

DTC No.

(See page)

Detection Item

Trouble Area

Memory

00

Normal

–

–

B1411/11 *

1

(DI–814)

Room temperature sensor circuit

S Room temp. sensor

S Harness or connector between room temp. sensor and A/C

ECU (Combination Meter ECU)

S A/C ECU (Combination Meter ECU)

f

(8.5 min. or more)

B1412/11*

2

(DI–817)

Ambient temperature sensor circuit

S Ambient temp. sensor

S Harness or connector between ambient temp. sensor and

A/C ECU (Combination Meter ECU)

S A/C ECU (Combination Meter ECU)

f

(8.5 min. or more)

B1413/13

(DI–820)

Evaporator temperature sensor circuit

S Evaporator temp. sensor

S Harness or connector between evaporator temp. sensor and

A/C ECU (Combination Meter ECU)

S A/C ECU (Combination Meter ECU)

f

(8.5 min. or more)

B1421/21 *

3

Solar sensor circuit

S Solar sensor

S Harness or connector between solar sensor and A/C ECU

–

B1421/21 *

3

(DI–823)

S Harness or connector between solar sensor and A/C ECU

(Combination Meter ECU)

S A/C ECU (Combination Meter ECU)

f

(8.5 min. or more)

B1422/22 *

4

(DI–826)

All conditions below are detected for 3

sec. or more

(a) Engine speed: 450 rpm or more

(b) Ratio between engine and compres-

sor rpm deviates 20% or more in com-

parison to normal operation.

S Compressor drive belt

S Compressor lock sensor

S Compressor

S Harness and connector between A/C ECU (Combination

Meter ECU) and compressor, compressor lock sensor

S A/C ECU (Combination Meter ECU)

–

B1423/23

(DI–829)

Open in pressure sensor circuit

Abnormal refrigerant pressure

[below 196 kPa (2.0 kgf/cm

2

, 28 psi)

over 3,140 kPa (32.0 kgf/cm

2

, 455 psi)]

S Pressure switch

S Harness or connector between pressure switch and A/C

ECU (Combination Meter ECU)

S Refrigerant pipe line

S A/C ECU (Combination Meter ECU)

–

B1431/31

(DI–832)

Air mix damper position sensor circuit

S Air mix damper position sensor

S A/C ECU (Combination Meter ECU)

S Harness or connector between air mix damper position sen-

sor and A/C ECU (Combination Meter ECU)

f

(1 min. or more)

B1432/32

(DI–835)

Air inlet damper position sensor circuit

S Air inlet damper position sensor circuit

S A/C ECU (Combination Meter ECU)

S Harness or connector between air inlet damper position

sensor and A/C ECU (Combination Meter ECU)

f

(1 min. or more)

B1433/33

(DI–838)

Air outlet damper position sensor circuit

S Air outlet damper position sensor circuit

S A/C ECU (Combination Meter ECU)

S Harness or connector between max cool damper position

sensor and A/C ECU (Combination Meter ECU)

f

(1 min. or more)

B1441/41

(DI–841)

Air mix damper control servomotor cir-

cuit (Passenger side)

S Air mix damper control servomotor

S Air mix damper position sensor

S Harness and connector between A/C ECU (Combination

Meter ECU) and air mix position sensor

S Harness and connector between A/C ECU (Combination

Meter ECU) and mix damper control servomotor

S A/C ECU (Combination Meter ECU)

f

(15secs. or more)