1991 LEXUS SC300 code 32

Check voltage between terminals TP1 and SG of air conditioner control
assembly connector.
(1) Remove console upper panel.(See page BO-111).
(2) Remove A/C control assembly with connec±
tors still connected.
(3) Turn ignition switch ON.
Press REC/FRS switch to change the air inlet
between fresh and recirculation air, and measure
voltage between terminals TP1 and SG of air
conditioner control assembly when the air inlet
servomotor operates.
In addition, as the air inlet servomotor is moved
from REC side to FRS side, the voltage de-
creases gradually without interruption.
Proceed to next circuit inspection shown on matrix chart
(See page AC-36).However, when Diag. code 32 or 42 is
displayed, check and replace air conditioner control assem-
bly.
Check air inlet damper position sensor.
(1) Remove heater unit. (See page AC-127)
(2) Disconnect air inlet servomotor assembly
connector.
Measure resistance between terminals S5 and SG of
air inlet servomotor assembly connector.
Resistance: 4.7~7.2 k

While operating air inlet servomotor as in the
procedure on page AC-65, measure resistance
between terminals TP1 and SG of air inlet servo-
motor assembly connector.
Resistance:
As the air inlet servomotor moves from REC side
to FRS side, the resistance decreases gradually
without interruption.
Replace air inlet servomotor assembly.
Check for open and short in harness and connector between air conditioner
control assembly and air inlet servomotor assembly (See page IN-27).
Repair or replace harness or connector.
Check and replace air conditioner control assembly.
INSPECTION PROCEDURE
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AIR CONDITIONING SYSTEM REPAIR INSTRUCTIONSAC±63
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Diag. Code 42Air Inlet Servomotor Circuit
CIRCUIT DESCRIPTION
The air inlet servomotor is controlled by the air conditioner control assem\
bly and moves the air inlet
damper to the desired position.
Code No.Diag. Code Detecting ConditionTrouble area
42
Air inlet damper position sensor value does
not change even if A/C control assembly oper-
ated air inlet servomotor
Air inlet damper position sensor.

Harness or connector between air inlet ser-
vomotor assembly and A/C control assem-
bly.

A/C control assembly
DIAGNOSTIC CHART
Actuator check.
Check air inlet servomotor.
Check harness and connector between air
conditioner control assembly and air inlet ser-
vomotor assembly (See page IN-27).
Check and replace air conditioner control
assembly.
Proceed to next circuit inspection
shown on matrix chart (See page
AC-36 ).
Replace air inlet servomotor
assembly.
Repair or replace harness or
connector.
AC±64±
AIR CONDITIONING SYSTEM Troubleshooting
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Diag. Code 33, 34 Air Outlet Damper Position Sensor Circuit
CIRCUIT DESCRIPTION
This sensor detects the position of the air outlet
damper and sends the appropriate signals to the
air conditioner control assembly.
The position sensor is built into the air outlet ser-
vomotor assembly.
Code No.Diag. Code Detecting ConditionTrouble area
33Short to ground or power source circuit in air
outlet damper position sensor circuit.
Air outlet damper position sensor.

Harness or connector between air outlet
servomotor assembly and A/C control as-
43
Air outlet damper position sensor value does
not change even if A/C control assembly
operates air outlet servomotor.servomotor assembly and A/C control as-
sembly

A/C control assembly
DIAGNOSTIC CHART
Check voltage between terminals TPM and
SG of air conditioner control assembly
connector.
Check air outlet damper position sensor.
Check harness and connector between air
conditioner control assembly and air outlet
servomotor assembly (See page IN±27).
Check and replace air conditioner control
assembly.
Proceed to next circuit inspection
shown on matrix chart (See page
AC-36 ). However, when Diag.
code 33 or 43 is displayed, check
and replace air conditioner control
assembly.
Replace air outlet servomotor
assembly.
Repair or replace harness or
connector.
AC±66±
AIR CONDITIONING SYSTEM Troubleshooting
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Check voltage between terminals TPM and SG of air conditioner control
assembly connector.
(1) Remove console upper panel.(See page BO-111 ).
(2) Remove A/C control assembly with
connectors still connected.
(3) Turn ignition switch ON.
In addition, as the air outlet servomotor is moved
from REC side to FRS side, the voltage decreases
gradually without interruption.
Proceed to next circuit inspection shown on matrix chart
(See page AC-36).However, when Diag. code 32 or 42 is dis-
played, check and replace air conditioner control assembly.
Check air outlet damper position sensor.
(1) Remove heater unit. (See page AC-127)
(2) Disconnect air outlet servomotor assembly
connector.
Measure resistance between terminals S5 and SG of
air outlet servomotor assembly connector.
Resistance: 4.7~7.2 k

While operating air outlet servomotor as in the
procedure on page AC-69, measure resistance
between terminals TP1 and SG of air outlet servo-
motor assembly connector.
Resistance:
As the air inlet servomotor moves from DEF side
to FACE side, the resistance decreases gradually
without interruption.
Replace air outlet servomotor assembly.
Check for open and short in harness and connector between air conditioner
control assembly and air outlet servomotor assembly (See page IN-27).
Repair or replace harness or connector.
Check and replace air conditioner control assembly.
INSPECTION PROCEDURE
±
AIR CONDITIONING SYSTEM TroubleshootingAC±67
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Diag. Code 43Air Outlet Servomotor Circuit
CIRCUIT DESCRIPTION
Code No.Diag. Code Detecting ConditionTrouble area
43Air outlet damper position sensor value does not
change even if A/C control assembly operated air
outlet servomotor.
Air outlet servomotor.

Air outlet damper position sensor.

Harness or connector between A/C control
assembly air outlet servomotor, air outlet
damper position sensor.

A/C control assembly
DIAGNOSTIC CHART
Actuator check.
Check air outlet servomotor.
Check harness and connector between air
conditioner control assembly and air outlet
servomotor, air outlet servomotor and bat-
tery, air outlet servomotor and body ground.
(See page IN-27).
Check and replace air conditioner control
assembly.
Proceed to next circuit inspection
show on matrix chart (See page
AC-36 ).
Replace air outlet servomotor .
Repair or replace harness or
connector.
AC±68±
AIR CONDITIONING SYSTEM Troubleshooting
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Back±up Power Source Circuit
CIRCUIT DESCRIPTION
This is the backup power source for the air conditioner control assembly. Power is supplied even when
the ignition switch is off and is used for diagnostic code memory, etc.
DIAGNOSTIC CHART
WIRING DIAGRAM
Check voltage between terminal B of air
conditioner control assembly connector
and body ground.
Check DOME fuse.
Proceed to next circuit inspection
shown on matrix chart (See page
AC-36
).
Check and repair harness and connector
between air conditioner control assembly
and battery.
Check for short all in the harness
and components connecteds to
the DOME fuse (See attached wiring
diagram)
AC±74±
AIR CONDITIONING SYSTEM Troubleshooting
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Diagnosis Circuit
CIRCUIT DESCRIPTION
This circuit sends signals to the A/C control assembly requesting output of \
diagnostic codes.
DIAGNOSTIC CHART
WIRING DIAGRAM
Check voltage between terminals Tc and
E1 of TDCL.
Check harness and connector between air
conditioner control assembly and TDCL and
body ground.
Proceed to next circuit inspection
shown on matrix chart (See page
AC-36
).
Repair or replace harness or
connector.
Check and replace air conditioner control
assembly.
AC±98±
AIR CONDITIONING SYSTEM Troubleshooting
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Diag. Code 14\
 \
Open in Squib Circuit
DIAGNOSTIC CHARTDIAGNOSTIC CHART
The squib circuit consists of the center airbag sensor assembly, spiral cable and the steering wheel pad
(squib). It causes the airbag to deploy when the airbag deployment con\
ditions are satisfied.
For details of the function of each component, see FUNCTION OF COMPONENT\
S on page AB±5.
Diagnostic code 14 is recorded when an open is detected in the squib cir\
cuit.
 Code No.\
 \
Diagnosis
 



14
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Open circuit in D+ wire harness or D wire harness of squib.
 Squib malfunction.
 Spiral cable malfunction.
 Center airbag sensor assembly malfunction.
AB±62±
SRS AIRBAG Troubleshooting
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