Lexus IS250 IS220d GSE20 ALE20 - AIR CONDITIONING
READ VALUE OF INTELLIGENT TESTER
INSPECT AIR CONDITIONING HARNESS
DTC B1413/13 Evaporator Temperature Sensor Circuit
DESCRIPTION
The evaporator temperature sensor (A/C thermistor) is installed on the evaporator in the air conditioner unit. It detects the temperature of the cooled air that has passed through the evaporator and its signal is used to control the air conditioning. It sends a signal to the A/C amplifier. The resistance of the evaporator temperature sensor (A/C thermistor) changes in accordance with the temperature of the cooled air that has passed through the evaporator. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.
The A/C amplifier applies voltage (5 V) to the evaporator temperature sensor (A/C thermistor) and reads voltage changes as the resistance of the evaporator temperature sensor (A/C thermistor) changes. This sensor is used to prevent the evaporator from freezing.
| DTC No. | DTC Detection Condition | Trouble Area |
| B1413/13 | Open or short in evaporator temperature sensor circuit | Air conditioning harness (evaporator temperature sensor) A/C amplifier |
WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.READ VALUE OF INTELLIGENT TESTER |
Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG) and turn the intelligent tester main switch on.
Select the item below in the Data List, and read the display on the intelligent tester.
| Item | Measurement Item / Display (Range) | Normal Condition | Diagnostic Note |
| Evaporator Temp Sensor (Evap Temp) | Evaporator temperature sensor / Min.: -29.7°C (-21.46°F), Max.: 59.55°C (139.19°F) | Actual evaporator temperature is displayed | Open in circuit: -29.7°C (-21.46°F) Short in circuit: 59.55°C (139.19°F) |
- OK:
- The display is as specified in the normal condition column.
- Result:
Result Proceed to NG A OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE) B OK (When troubleshooting according to the DTC) C
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| A | |
| 2.INSPECT AIR CONDITIONING HARNESS |
Remove the air conditioning harness (evaporator temperature sensor).
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
Tester Connection Condition Specified Condition e1-5 - e1-6 -10°C (14°F) 7.30 to 9.10 kΩ e1-5 - e1-6 -5°C (23°F) 5.65 to 6.95 kΩ e1-5 - e1-6 0°C (32°F) 4.40 to 5.35 kΩ e1-5 - e1-6 5°C (41°F) 3.40 to 4.15 kΩ e1-5 - e1-6 10°C (50°F) 2.70 to 3.25 kΩ e1-5 - e1-6 15°C (59°F) 2.14 to 2.58 kΩ e1-5 - e1-6 20°C (68°F) 1.71 to 2.05 kΩ e1-5 - e1-6 25°C (77°F) 1.38 to 1.64 kΩ e1-5 - e1-6 30°C (86°F) 1.11 to 1.32 kΩ
- NOTICE:
- HINT:
- As the temperature increases, the resistance decreases (see the graph).
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| OK | ||
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