2001 TOYOTA SEQUOIA air conditioning

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

± 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.

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

I28836
Integration Control
and Panel
PSW L±B
R±YR±Y
4A4
A/C Pressure Switch
I19
C46
IA5
1
J3
J/C
From
HTR FuseL±B
CDual
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±2343
2537 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

I29010
Pressure switch:
A4
DI±2344
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2538 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check refrigerant pressure.
(a) Set the manifold gauge.
(b) Read the manifold gauge pressure when these conditions are established.
Test conditions:

Temperature at the air inlet with the switch set at RECIRC is 30 to 35°C (86 to 95°F)

Engine running at 1,500 rpm

Blower speed control switch at ºHIº position

Temperature control dial at ºCOOLº position

Air conditioning switch ON

Fully open doors
Standard:
Pressure on high pressure side:
1.37 to 1.57 MPa (13.9 to 16.0 kgfVcm
2, 198 to 228 psi)
HINT:
If the refrigerant pressure is below 196 KPa (2.0 kgfVcm
2, 28 psi), the refrigerant amount the air conditioning
cycle may have decreased significantly for reasons such as a gas leakage.
NG Check air conditioning cycle
(See page AC±3).
OK
2 Check air conditioning operation.
(a) Disconnect the pressure switch connector.
(b) Connect terminals 1 and 4 of the connector of the pres-
sure switch on the vehicle wire harness side using a ser-
vice wire.
(c) Start the engine.
(d) Turn the air conditioning switch is on and check that the
magnet clutch is turned on.
(e) Check that the magnet clutch is turned off when discon-
necting terminals 1 and 4 (that are connected in the prior
step).
OK:
Terminals 1 and 4 connected: magnet clutch is on
Terminals 1 and 4 disconnected: magnet clutch is off
NG Go to step 3.
OK

± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±2345
2539 Author: Date:
2005 SEQUOIA (RM1146U)
Replace pressure switch.
3 Check harness and connector between pressure switch and integration control
and panel (See page IN±35).
Result:
NGA
OK (Checking from the PROBLEM SYMPTOMS TABLE)B
OK (Checking from the DTC)C
A Repair or replace harness or connector.
B Proceed to next circuit inspection shown in
problem symptoms table (See page DI±2304).
OK
Replace integration control and panel.

4 (V)
1
TP terminal voltage0 100 %
(Cool)
(Hot)
Damper opening angle
I28837
A17
Air Mix Control
Servomotor (Front)
5
L±R 4 322
15
12S5±AM
TP
SG±TP Integration Control
and Panel
I20 R±Y
G±R VZ
PT
GNDI20
I20 DI±2346
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2540 Author: Date:
2005 SEQUOIA (RM1146U)
DTC 31 Front Air Mix Damper Position Sensor Cir-
cuit
CIRCUIT DESCRIPTION
This sensor detects the position of the air mix damper and
sends the appropriate signals to the integration control and
panel.
The position sensor is built into the air mix damper control ser-
vomotor assembly.
DTC No.Detection ItemTrouble Area
31Short to ground or short to power source circuit in front air mix

Front air mix damper position sensor

Harness or connector between front air mix damper position
31Short to ground or short to ower source circuit in front air mix
damper position sensor circuit.

Harness or connector between front air mix dam er osition
sensor and integration control and panel

Integration control and panel
WIRING DIAGRAM
DI3FF±10

I28847
SG±TP TPI20 Integration Control and Panel:
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±2347
2541 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check voltage between terminals TP and SG±TP of integration control and pan-
el.
PREPARATION:
Remove the integration control and panel with connectors still
connected.
CHECK:
(a) Turn the ignition switch to ON.
(b) Change the set temperature to activate the front air mix
damper control servomotor, and measure the voltage be-
tween terminals TP and SG±TP of the integration control
and panel connector each time the set temperature is
changed.
OK:
Set TemperatureVoltage
Max. cool3.5 to 4.5 V
Max. hot0.5 to 1.5 V
HINT:
As the set temperature increases, the voltage decreases.
NG Go to step 2.
Ok
Proceed to next circuit inspection shown in problem symptoms table (See page DI±2304). How-
ever, if DTC 31 is displayed, replace integration control and panel.