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 from step 2.

Check solar sensor using LEXUS hand-held tester.
PREPARATION:

Connect the LEXUS hand-held tester to the DLC3.

CHECK:

Check the solar sensor using DATA LIST.
1. OK : Check and replace A/C ECU.
2. NG : Go to next step.

Check voltage between terminals TSPa and GND of A/C ECU connector.

PREPARATION:

Remove A/C ECU with connectors still connected.

CHECK:

Turn ignition switch to ON.
Measure voltage between terminals TSPa and GND of A/C ECU connector when the solar sensor is subjected to an electric light, and when the sensor is covered with a cloth.

Fig 1: Identifying Terminals TSPa And Gnd Of A/C ECU Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK:

VOLTAGE CONDITION SPECIFICATION

Condition	Voltage
Sensor subjected to electric light	0.8 - 4.3 V
Sensor covered by a cloth	Below 0.8 V

HINT:

As the inspection light is moved away from the sensor, the voltage increases.

NG : Go to step 3.
OK : Proceed to next circuit inspection shown on problem symptoms table (See PROBLEM SYMPTOMS TABLE ). However, if DTC B1421/21 is displayed, check and replace A/C ECU.

Check wire harness
PREPARATION:

Disconnect the connector of solar sensor and A/C ECU.

CHECK:

Check the continuity between wire harness and body ground.

OK:

Resistance: No continuity

Fig 2: Checking Wiring Harness
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Repair or replace the wire harness.
2. OK : Go to next step.
Check A/C ECU.
PREPARATION:

Connect the connector of A/C ECU.

CHECK:

Check the DTC.

OK:

B1221/21 is not output.

Fig 3: Checking A/C ECU
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Replace the A/C ECU.
2. OK : Replace the solar sensor.