TOYOTA SIENNA 2007 Service Repair Manual

AC–48AIR CONDITIONING – AIR CONDITIONING SYSTEM (for Automatic Air Conditioning Sys-
tem)
AC
SYSTEM DESCRIPTION
The ECM sends an engine speed signal to the A/C amplifier via CAN communication and BEAN
communication.
The A/C amplifier reads the difference between compressor speed and engine speed. When the
difference becomes too large, the A/C amplifier determines that the compressor locks, and turns the
magnetic clutch off.
WIRING DIAGRAM
INSPECTION PROCEDURE
(a) Use the intelligent tester to check if the CAN
communication system is functioning normally.
DTC B1422/22 Compressor Lock Sensor Circuit
DTC No. DTC Detection Condition Trouble Area
B1422/22 Open or short in compressor lock sensor circuit• A/C compressor (A/C lock sensor)
• Compressor drive belt
• Harness or connector between compressor and
magnetic clutch (A/C lock sensor)
• A/C amplifier
• CAN communication system
• Multiplex communication system (BEAN)
1CHECK CAN COMMUNICATION SYSTEM
E147293E02

AIR CONDITIONING – AIR CONDITIONING SYSTEM (for Automatic Air Conditioning Sys-
tem)AC–49
AC
Result
B
A
(a) Use the intelligent tester to check if the multiplex
communication system (BEAN) is functioning normally.
Result
B
A
(a) Remove the A/C amplifier with the connectors still
connected.
(b) Measure the waveform of the connector.
Result Proceed to
CAN DTC is not output A
CAN DTC is output B
GO TO CAN COMMUNICATION SYSTEM
2CHECK MULTIPLEX COMMUNICATION SYSTEM
Result Proceed to
BEAN DTC is not output A
BEAN DTC is output B
GO TO MULTIPLEX COMMUNICATION
SYSTEM
3INSPECT A/C AMPLIFIER
E145185E01
E116941E03
Item Contents
Tool setting 200 mV/DIV., 10 ms./DIV.
Vehicle conditionEngine is running
A/C switch: ON
Blower switch: LO

AC–50AIR CONDITIONING – AIR CONDITIONING SYSTEM (for Automatic Air Conditioning Sys-
tem)
AC
Standard
Result
B
C
A
(a) Disconnect the connector from the A/C compressor.
(b) Measure the resistance according to the value(s) in the
table below.
Standard resistance
NG
OK
Tester Connection Condition Specified Condition
A9-9 (LOCK) - A9-24
(SG-6)Engine is running
A/C switch: ON
Blower switch: LOPulse generation
Result Proceed to
NG A
OK (When troubleshooting according to the
PROBLEM SYMPTOMS TABLE)B
OK (When troubleshooting according to the DTC) C
PROCEED TO NEXT CIRCUIT INSPECTION
SHOWN IN PROBLEM SYMPTOMS TABLE
REPLACE A/C AMPLIFIER
4INSPECT COMPRESSOR AND MAGNETIC CLUTCH (A/C LOCK SENSOR)
E145186E01
Tester Connection Condition Specified Condition
A31-1 (SSR+) - A31-2
(SSR-)Always (at 20
C (68F)) 165 to 205
REPLACE COMPRESSOR AND MAGNETIC
CLUTCH (A/C LOCK SENSOR)

AIR CONDITIONING – AIR CONDITIONING SYSTEM (for Automatic Air Conditioning Sys-
tem)AC–51
AC
(a) Disconnect the connector from the A/C amplifier.
(b) Measure the resistance according to the value(s) in the
table below.
Standard resistance
NG
OK
5CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C LOCK SENSOR)
E143742E29
E124442E07
Tester Connection Condition Specified Condition
A9-9 (LOCK) - A31-1
(SSR+)Always Below 1
A9-24 (SG-6) - A31-2
(SSR-)Always Below 1
A9-9 (LOCK) - Body
groundAlways 10 k or higher
A9-24 (SG-6) - Body
groundAlways 10 k
or higher
REPAIR OR REPLACE HARNESS OR
CONNECTOR
REPLACE A/C AMPLIFIER

AC–52AIR CONDITIONING – AIR CONDITIONING SYSTEM (for Automatic Air Conditioning Sys-
tem)
AC
DESCRIPTION
This DTC is output when refrigerant pressure on the high pressure side is extremely low (0.19 MPa (2.0
kgf/cm
2, 28 psi) or less) or extremely high (3.14 MPa (32.0 kgf/cm2, 455 psi) or more). The pressure
sensor, which is installed on the pipe of the high pressure side to detect refrigerant pressure, outputs a
refrigerant pressure signal to the A/C amplifier. The A/C amplifier converts this signal to pressure
according to the sensor characteristics to control the compressor.
DTC B1423/23 Pressure Sensor Circuit
DTC No. DTC Detection Condition Trouble Area
B1423/23• Open or short in pressure sensor circuit
• Refrigerant pressure on the high pressure side is
extremely low (0.19 MPa (2.0 kgf/cm
2, 28 psi) or
less) or extremely high (3.14 MPa (32.0 kgf/cm2,
455 psi) or more).• Pressure sensor
• Harness or connector between pressure sensor
and A/C amplifier
• A/C amplifier
• Expansion valve (blocked, stuck)
• Condenser (blocked, deterioration of cooling
capacity due to dirt)
• Cooler dryer (moisture in the refrigerant cycle
cannot be absorbed)
• Cooling fan system (condenser cannot be cooled
down)
• A/C system (leaks, blocked)

AIR CONDITIONING – AIR CONDITIONING SYSTEM (for Automatic Air Conditioning Sys-
tem)AC–53
AC
WIRING DIAGRAM
E116878E10

AC–54AIR CONDITIONING – AIR CONDITIONING SYSTEM (for Automatic Air Conditioning Sys-
tem)
AC
INSPECTION PROCEDURE
(a) Disconnect the connector from the A/C pressure sensor.
(b) Measure the voltage according to the value(s) in the
table below.
Standard voltage
NG
OK
(a) Measure the resistance according to the value(s) in the
table below.
Standard resistance
NG
OK
(a) Reconnect the connector to the A/C pressure sensor.
1CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)
E124477E13
Tester Connection Condition Specified Condition
A33-3 (+) - Body ground Ignition switch ON Approx. 5 V
Go to step 5
2CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)
E124477E14
Tester Connection Condition Specified Condition
A33-1 (-) - Body ground Always Below 1
Go to step 6
3INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)

AIR CONDITIONING – AIR CONDITIONING SYSTEM (for Automatic Air Conditioning Sys-
tem)AC–55
AC
(b) Remove the A/C amplifier with connectors still
connected.
(c) Measure the voltage according to the value(s) in the
table below.
Standard voltage
HINT:
If the measured voltage is not within the normal range,
there may be a malfunction in the A/C amplifier, A/C
pressure sensor, or wire harness. It is also possible that
the amount of refrigerant may not be appropriate.
NG
OK
(a) Measure the voltage when the following conditions are
satisfied.
NOTICE:
• If refrigerant pressure on the high pressure side
becomes extremely high during the inspection (if
the voltage exceeds 4.8 V), the fail-safe function
stops compressor operation. Therefore, measure
the voltage before the fail-safe operation.
• It is necessary to measure the voltage for a
certain amount of time (approximately 10
minutes) because the problem symptom may
recur after a while.
HINT:
When the outside air temperature is low (below -1.5
C
(29.3
F)), the compressor stops due to operation of the
ambient temperature sensor and the evaporator
temperature sensor to prevent the evaporator from
freezing. In this case, perform the inspection in a warm
indoor environment.
E145185E02
Tester Connection Condition Specified Condition
A9-35 (PRE) - Body
groundIgnition switch ON
(A/C: OFF)0.7 to 4.8 V
Go to step 7
4INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT)
Item Condition
Vehicle Doors Fully open
Temperature Setting MAX COLD
Blower Speed HI
A/C Switch ON
R/F Switch RECIRCULATION
Interior Temperature 25 to 35
C (77 to 95F)
Engine Speed 2000 rpm

AC–56AIR CONDITIONING – AIR CONDITIONING SYSTEM (for Automatic Air Conditioning Sys-
tem)
AC
(1) Measure the voltage according to the value(s) in the
table below.
Standard voltage
Result
B
C
A
(a) Disconnect the connector from the A/C amplifier.
E145185E02
Tester Connection Condition Specified Condition
A9-35 (PRE) - Body
groundIgnition switch ON
(A/C: ON)0.7 to 4.8 V
Result Proceed to
OK (When troubleshooting according to DTC) A
OK (When troubleshooting according to
PROBLEM SYMPTOMS TABLE)B
NG C
PROCEED TO NEXT CIRCUIT INSPECTION
SHOWN IN PROBLEM SYMPTOMS TABLE
Go to step 13
REPLACE A/C AMPLIFIER
5CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR)
E143742E30

AIR CONDITIONING – AIR CONDITIONING SYSTEM (for Automatic Air Conditioning Sys-
tem)AC–57
AC
(b) Measure the resistance according to the value(s) in the
table below.
Standard resistance
NG
OK
(a) Disconnect the connector from the A/C amplifier.
E124477E13
Tester Connection Condition Specified Condition
A33-3 (+) - A9-10 (S5-5) Always Below 1
A9-10 (S5-5) - Body
groundAlways 10 k or higher
REPAIR OR REPLACE HARNESS OR
CONNECTOR
REPLACE A/C AMPLIFIER
6CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR)
E143742E31