Inspection Procedure

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

In case of using the LEXUS hand-held tester start the inspection step 1 and in case of not using the LEXUS hand-held tester, start form step 2.

Check evaporator temperature sensor using LEXUS hand-held tester.
PREPARATION:

Connect the LEXUS hand-held tester to the DLC3.

CHECK:

Check the evaporator temperature sensor using DATA LIST.
1. OK : Check and replace A/C ECU.
2. NG : Go to next step.
Check voltage between terminals TE and SG-7 of A/C ECU connector.
PREPARATION:

Remove A/C ECU with connectors still connected.

CHECK:
1. Turn ignition switch to ON.
2. Measure voltage between terminals TE and SG-7 of A/C ECU connector at each temperature.
OK:

Voltage :

at 0°C (32°F) : 2.0 - 2.4 V

at 15°C (59°F) : 1.4 - 1.8 V

Fig 1: Identifying Terminals TE And Sg-7 Of A/C ECU Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

As the temperature increases, the voltage decreases.
1. NG : Go to step 3.
2. OK : Proceed to next circuit inspection shown on problem symptoms table (See PROBLEM SYMPTOMS TABLE ). However, if DTC B1413/13 is displayed, check and replace A/C ECU.
Check evaporator temperature sensor.
PREPARATION:

Remove evaporator temperature sensor (See THERMISTOR ).

CHECK:

Measure resistance between terminals 1 and 2 of evaporator temperature sensor connector at each temperature.

OK:

Resistance :

at 0°C (32°F) : 4.76 - 4.95 kΩ

at 15°C (59°F) : 2.22 - 2.46 kΩ

HINT:

As the temperature increases, the resistance decreases.

Fig 2: Identifying Evaporator Temperature Sensor
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Replace evaporator temperature sensor.
2. OK : Go to next step.
Check harness and connector between A/C ECU and evaporator temperature sensor (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).
1. NG : Repair or replace harness or connector.
2. OK : Check and replace A/C ECU.