Lexus ES300 (2002 year). Manual - part 324

I30099

Heater Control Housing Sub-assy
(A/C Amplifier)

A1
A/C Ambient
Temp. Sensor

TAM

8

1

2

IF7

B-W

G-R

A15

IF7

4

5

SG-6

39

A15

G-R

B-W

-

DIAGNOSTICS

AIR CONDITIONING SYSTEM

05-473

626

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

12

AMBIENT TEMPERATURE SENSOR CIRCUIT

CIRCUIT DESCRIPTION

This sensor detects the temperature outside the cabin and sends the appropriate signals to the A/C amplifier.

DTC No.

Detection item

Trouble Area

12

Open or short in ambient temperature sensor circuit

Ambient temperature sensor

Harness or connector between ambient temperature sensor
and A/C amplifier

A/C amplifier

WIRING DIAGRAM

056CM-01

I30155

I30156

Resistance (k

Ω

)

Temperature (



C)

05-474

-

DIAGNOSTICS

AIR CONDITIONING SYSTEM

627

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

1

INSPECT COOLER (AMBIENT TEMP. SENSOR) THERMISTOR

(a)

Remove cooler (ambient temp. sensor) thermistor.

(b)

Measure resistance between terminals 1 and 2 of cooler
(ambient temp. sensor) thermistor connector at each tem-
perature.
Resistance: 
at 25  



C (77 



F) : 1.65 - 1.75 k

Ω

at 40 



C (104 



F) : 0.85 - 0.95 k

Ω

HINT:
As the temperature increases, the resistance decreases.

NG

REPLACE COOLER (AMBIENT TEMP. SENSOR)
THERMISTOR

OK

2

CHECK HARNESS AND CONNECTOR(COOLER(AMBIENT
TEMP.SENSOR)THERMISTOR AND CLOCK ASSY)

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

CHECK AND REPLACE HEATER  CONTROL  HOUSING  SUB-ASSY

0527H-03

05-384

-

DIAGNOSTICS

ELECTRONIC CONTROLLED AUTOMATIC
TRANSAXLE [ECT]

537

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

ELECTRONIC CONTROLLED AUTOMATIC
TRANSAXLE[ECT]

HOW TO PROCEED WITH TROUBLESHOOTING

1

Vehicle Brought to Workshop

2

Customer Problem Analysis (See page 

05-387

)

3

Connect the OBD II scan tool or hand-held tester to DLC3

4

Check and Clear DTC and Freeze Frame Data (See page 

05-388

)

5

Visual Inspection

6

Setting the Check Mode Diagnosis (See page 

05-388

)

7

Problem Symptom Confirmation

Symptom does not occur: Go to step 8

Symptom occur: Go to step 9

8

Symptom Simulation (See page 

01-21

)

9

DTC Check (See page 

05-388

)

DTC is not output: Go to step 10

DTC is output: Go to step 17

-

DIAGNOSTICS

ELECTRONIC CONTROLLED AUTOMATIC
TRANSAXLE [ECT]

05-385

538

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

10

Basic Inspection (See page 

05-388

)

NG

Go to step 19

OK

11

Mechanical System Test (See page 

05-388

)

NG

Go to step 16

OK

12

Manual Shifting Test (See page 

05-388

)

NG

Go to step 14

OK

13

Problem Symptoms Table Chapter 1 (See page 

05-406

)

NG

Go to step 18

OK

14

Problem Symptoms Table Chapter 2 (See page 

05-406

)

NG

Go to step 16

OK

15

Problem Symptoms Table Chapter 3 (See page 

05-406

)

NG

16

Part Inspection

Go to step 19

17

DTC Chart (See page 

05-400

)

18

Circuit Inspection (See page 

05-410

)