Toyota Sequoia (2005). Manual - part 635

I08309

2

1

I28970

Resistance (k

Ω

)

Temperature

4.0

2.0

3.5

1.5

0.0

10

3.0

1.0

2.5

0.5

20

30

40

50

60

68

86

104

122

140

(



C)

(



F)

50

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–2335

2529

2

Check rear room temperature sensor.

PREPARATION:
Disconnect the rear room temperature sensor connector.
CHECK:
Measure the resistance between terminals 1 and 2 of the room
temperature sensor connector at each temperature.
OK:

Tester connection

Condition

Specified condition

1–2

10



C (50



F)

3.00 to 3.73 k

Ω

1–2

15



C (59



F)

2.45 to 2.88 k

Ω

1–2

20



C (68



F)

1.95 to 2.30 k

Ω

1–2

25



C (77



F)

1.60 to 1.80 k

Ω

1–2

30



C (86



F)

1.28 to 1.47 k

Ω

1–2

35



C (95



F)

1.00 to 1.22 k

Ω

1–2

40



C (104



F)

0.80 to 1.00 k

Ω

1–2

45



C (113



F)

0.65 to 0.85 k

Ω

1–2

50



C (122



F)

0.50 to 0.70 k

Ω

1–2

55



C (131



F)

0.44 to 0.60 k

Ω

1–2

60



C (140



F)

0.36 to 0.50 k

Ω

NOTICE:

Even slightly touching the sensor may change the re-
sistance value. Be sure to hold the connector of the
sensor.

When measuring, the sensor temperature must be
the same as the ambient temperature.

HINT:
As the temperature increases, the resistance decreases (see
the graph on the left).

NG

Replace rear room temperature sensor.

OK

3

Check harness and connector between rear room temperature sensor and in-
tegration control and panel (See page 

IN–35

).

NG

Repair or replace harness or connector.

OK

Replace integration control and panel.

Resistance of photo diode

High

Low

Weak

Strong

Strength of solar radiation

I28834

A15
Solar
Sensor

TS

21

Integration Control and Panel

14

S5–TS

I20

B

LG

1

2

I20

DI–2336

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

2530

DTC

21

Solar Sensor Circuit

CIRCUIT DESCRIPTION

A photo diode in the solar sensor detects solar radiation and
sends signals to the integration control and panel.

DTC No

Detection Item

Trouble Area

21

Open or short in solar sensor circuit.

Note that output 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 integration

control and panel

Integration control and panel

WIRING DIAGRAM

DI3FB–11

I28847

TS

S5–TR

I20

Integration Control and Panel:

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–2337

2531

INSPECTION PROCEDURE

1

Check voltage between terminals TS and S5–TS of integration control and panel.

PREPARATION:
Remove the integration control and panel with connectors still
connected.
CHECK:
(a)

Turn the ignition switch to ON.

(b)

Measure the voltage between terminals TS and S5–TS of
the integration control and panel connector when the so-
lar sensor is subjected to an electric light, and when the
sensor is covered by a cloth.

OK:

Condition

Voltage

Move the light away from the sensor

Voltage increases

Move the light closer to the sensor

Voltage decreases

HINT:
Use an incandescent lamp for inspection. Bring it within 30 cm
(11.8 in.) of the solar sensor.

NG

Go to step 2.

OK

Proceed to next circuit inspection shown in problem symptoms table (See page 

DI–2304

). How-

ever, if DTC 21 is displayed, replace integration control and panel.

I08308

1

2

DI–2338

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

2532

2

Check solar sensor.

PREPARATION:
Remove the solar sensor.
CHECK:
(a)

Cover the sensor with a cloth.

(b)

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

HINT:
Connect the positive (+) lead of the ohmmeter to terminal 2 and
the negative (–) lead to terminal 1 of the solar sensor.
OK:

Tester connection

Condition

Specified condition

A15–1 – A15–2

Sensor is subject to elec-

tric light

Except 

∞

 

Ω

A15–1 – A15–2

Sensor is covered with a

cloth

∞

 

Ω

 (No continuity)

NOTICE:
The connection procedure for using a digital tester such as
an TOYOTA electrical tester is shown above. When using
an analog tester, connect the positive (+) lead to terminal
1 and negative (–) lead to terminal 2 of the A/C solar sensor.
HINT:

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

Use an incandescent lamp for inspection. Bring it within
30 cm (11.8 in.) of the A/C solar sensor.

NG

Replace solar sensor.

OK

3

Check harness and connector between solar sensor and integration control and
panel (See page 

IN–35

).

NG

Repair or replace harness or connector.

OK

Replace integration control and panel.