Page 2537 of 4323

I08309
21
I28970
Resistance (kW)
Temperature
4.0
2.0 3.5
1.5
0.0
10 3.0
1.0 2.5
0.5
20 30 40 5060
68 86 104 122140
(C)
(F) 50
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±2335
2529 Author: Date:
2005 SEQUOIA (RM1146U)
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 connectionConditionSpecified condition
1±210C (50F)3.00 to 3.73 kW
1±215C (59F)2.45 to 2.88 kW
1±220C (68F)1.95 to 2.30 kW
1±225C (77F)1.60 to 1.80 kW
1±230C (86F)1.28 to 1.47 kW
1±235C (95F)1.00 to 1.22 kW
1±240C (104F)0.80 to 1.00 kW
1±245C (113F)0.65 to 0.85 kW
1±250C (122F)0.50 to 0.70 kW
1±255C (131F)0.44 to 0.60 kW
1±260C (140F)0.36 to 0.50 kW
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.
Page 2538 of 4323
Resistance of photo diode
High
Low
Weak
Strong
Strength of solar radiation
I28834
A15
Solar
Sensor
TS 21 Integration Control and Panel
14S5±TS
I20 B
LG 1
2
I20 DI±2336
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2530 Author: Date:
2005 SEQUOIA (RM1146U)
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 NoDetection ItemTrouble 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
Page 2539 of 4323
I28847
TS
S5±TRI20 Integration Control and Panel:
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±2337
2531 Author: Date:
2005 SEQUOIA (RM1146U)
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:
ConditionVoltage
Move the light away from the sensorVoltage increases
Move the light closer to the sensorVoltage 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.
Page 2540 of 4323

I0830812
DI±2338
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2532 Author: Date:
2005 SEQUOIA (RM1146U)
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 connectionConditionSpecified condition
A15±1 ± A15±2Sensor is subject to elec-
tric lightExcept 8 W
A15±1 ± A15±2Sensor is covered with a
cloth8 W (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.
Page 2541 of 4323

I28835
24
Y±B W±R
A3
A/C Magnetic Clutch
and Lock Sensor 2
1IG4
SG±TAM Integration Control
and Panel
13
I19LOCK
20
I19 Y±B W±R
J14
J/C
AA 23
Y±B
IG4
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±2339
2533 Author: Date:
2005 SEQUOIA (RM1146U)
DTC 22 Compressor Lock Sensor Circuit
CIRCUIT DESCRIPTION
This sensor sends 1 pulse per engine revolution to the integration control and panel.
If the compressor speed divided by the engine speed is smaller than a predetermined value, the integration
control and panel turns the compressor OFF. The indicator flashes at about 1 second intervals.
DTC No.Detection ItemTrouble Area
22
All conditions below are detected for 3 sec. or more
(a) Engine speed: 450 rpm or more
(b) Ratio of engine to compressor speed deviates 20% or more
in comparison to normal operation.
Compressor drive belt
Compressor lock sensor
Compressor
Harness or connector between compressor lock sensor and
integration control and panel
Integration control and panel
WIRING DIAGRAM
DIDKY±01
Page 2542 of 4323

I05252
21
N02774
0.2 V/Din.
LOCK IN signal waveform
0 V
20 msec/Division (Idling)
DI±2340
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2534 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check compressor.
PREPARATION:
(a) Check and adjust compressor drive belt tension (See page AC±15).
CHECK:
(a) Check that the compressor does not lock when starting the engine and turning the A/C switch on.
OK: Cooler compressor assy does not lock during operation
HINT:
If the compressor drive belt slips when the A/C switch is on, the magnet clutch seems to be locked.
If the condition continues for more than 3 seconds, the A/C amplifier turns off the magnet clutch for compres-
sor drive belt protection.
NG Replace compressor.
OK
2 Check compressor lock sensor.
PREPARATION:
Disconnect the compressor connector.
CHECK:
Measure the resistance between terminals 1 and 2 of the com-
pressor lock sensor connector.
OK:
Resistance : 65 to 125 W at 20°C (68 °F)
Reference: Inspection using oscilloscope
During cranking or idling, measure the voltage between termi-
nals LOCK and SG±TAM of the integration control and panel.
HINT:
The correct waveform appears as shown in the illustration on
the left.
NG Replace compressor.
OK
Page 2543 of 4323
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±2341
2535 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check harness and connector between compressor lock sensor and integration
control and panel (See page IN±24).
NG Repair or replace harness or connector.
OK
Replace integration control and panel.
Page 2544 of 4323
I29011
ON (Below 1.0 W) Low pressure side High pressure side
OFF
(10 kW or higher)OFF
(10 kW or higher) (2.0 kgfVcm
2, 28 psi) (32.0 kgfVcm2, 455 psi) 196 KPa 3,140 KPa DI±2342
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2536 Author: Date:
2005 SEQUOIA (RM1146U)
DTC 23 Pressure Switch Circuit
CIRCUIT DESCRIPTION
The pressure switch sends the appropriate signals to the A/C
amplifier when the A/C refrigerant pressure drops too low or
rises too high. When the A/C amplifier receives these signals,
it outputs signals through the A/C amplifier to turn the magnet
clutch relay off and turns the magnetic clutch off.
DTC No.Detection ItemTrouble Area
23
Open in pressure sensor circuit.
Abnormal refrigerant pressure.
below 196 kPa (2.0 kg/cm
2, 28 psi)
over 3,140 kPa (32.0 kgf/cm2, 455 psi)
Pressure switch
Harness or connector between pressure switch and integra-
tion control and panel
Refrigerant pipe line
Integration control and panel
DI3FD±09