Last Modified: 7-3-2017 6.8:8.0.40 Doc ID: RM0000018N4004X
Model Year Start: 2007 Model: LX470 Prod Date Range: [08/2006 -           ]
Title: AIR CONDITIONING: AIR CONDITIONING SYSTEM: 21; Solar Sensor Circuit; 2007 MY LX470 [08/2006 -        ]

DTC

21

Solar Sensor Circuit

DESCRIPTION

A photodiode in the solar sensor detects solar radiation and sends signals to the A/C amplifier.

DTC No.

Detection Item

Trouble Area

21

Open or short in solar sensor circuit

Please note that display of diagnostic trouble code 21 is not abnormal when the sensor is not receiving solar radiation
  • Solar sensor
  • Harness or connector between solar sensor and A/C amplifier
  • A/C amplifier

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK AIR CONDITIONING AMPLIFIER

(a) Remove the A/C amplifier with the connectors still connected.

(b) Turn the ignition switch ON.

(c) Measure the voltage between terminals FRS5 (A48-9) and TS (A48-8) of the A/C amplifier connector when the solar sensor is subjected to an electric light, and when the sensor is covered with a cloth.

Standard voltage:

Condition

Specified Condition

Sensor subjected to electric light

0.8 to 4.3 V

Sensor covered with a cloth

Below 0.8 V

HINT:

  • As the inspection light is moved away from the sensor, the voltage increases.
  • However, if DTC 21 is displayed, check and replace the A/C amplifier.
OK

REPLACE AIR CONDITIONING AMPLIFIER

NG

2.

CHECK SOLAR SENSOR

(a) Remove the solar sensor.

(b) Connect the positive (+) lead of ohmmeter to terminal 2 and negative (-) lead to terminal 1 of the solar sensor.

(c) Measure the resistance between terminals 1 and 2 of the solar sensor connector.

Standard resistance:

Tester Connection

Condition

Specified Condition

1 - 2

Sensor subjected to electric light

Excep ∞ Ω

1 - 2

Sensor is covered with a cloth

∞ Ω

NOTICE:

The connection procedure for a digital tester, such as a TOYOTA electrical tester, is shown above. When using an analog tester, connect the negative (-) lead to terminal 1 and positive (+) lead to terminal 2.

HINT:

  • As the inspect light is moved away from the sensor, the resistance increases.
  • Use an in incandescent light for inspection. Bring it within 30 cm (11.8 in.) of the A/C solar sensor.
NG

REPLACE SOLAR SENSOR

OK

3.

CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - SOLAR SENSOR)
NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

REPLACE AIR CONDITIONING AMPLIFIER