Unified NISSAN TEANA 2003 Owner's Manual

ATC-64
TROUBLE DIAGNOSIS

SYSTEM DESCRIPTION
Component Parts
Mode door control system components are:

Unified meter and A/C amp.

Mode door motor (LCU)

A/C LAN system (PBR built-in mode door motor, air mix door motor and intake door motor)

In-vehicle sensor

Ambient sensor

Sunload sensor

Intake sensor
System Operation
The unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp.
sends air mix door, mode door and intake door opening angle data to the air mix door motor LCU, mode door
motor LCU and intake door motor LCU.
The air mix door motor, mode door motor and intake door motor read their respective signals according to the
address signal. Opening angle indication signals received from the unified meter and A/C amp. and each of
the motor position sensors are compared by the LCUs in each door motor with the existing decision and open-
ing angles. Subsequently, HOT/COLD, DEF/VENT and FRE/REC operation is selected. The new selection
data is returned to the unified meter and A/C amp.
RJIA1777E

TROUBLE DIAGNOSIS
ATC-67
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SYSTEM DESCRIPTION
Component Parts
Air mix door control system components are:

Unified meter and A/C amp.

Air mix door motor (LCU)

A/C LAN system (PBR built-in mode door motor, air mix door motor and intake door motor)

In-vehicle sensor

Ambient sensor

Sunload sensor

Intake sensor
System Operation
The unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp.
sends air mix door, mode door and intake door motor opening angle data to the air mix door motor LCUs,
mode door motor LCU and intake door motor LCU.
The air mix door motors, mode door motor and intake door motor read their respective signals according to the
address signal. Opening angle indication signals received from the unified meter and A/C amp. and each of
the motor position sensors are compared by the LCUs in each door motor with the existing decision and open-
ing angles. Subsequently, HOT/COLD, DEF/VENT and FRE/REC operation is selected. The new selection
data are returned to the unified meter and A/C amp.
Air Mix Door Control Specification
RJIA1781E
RJIA1782E

ATC-68
TROUBLE DIAGNOSIS

COMPONENT DESCRIPTION
Air Mix Door Motor
The air mix door motors are attached to the heater & cooling unit
assembly. It rotates so that the air mix door is opened or closed to a
position set by the unified meter and A/C amp. Air mix door rotates
gear of slide door directly and moves slide door.
DIAGNOSIS PROCEDURE FOR AIR MIX DOOR MOTOR
SYMPTOM: Discharge air temperature does not change.
Perform diagnosis procedure. Refer to AT C - 5 9 , "
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT" .
Air Mix Door Motor PBR CircuitBJS000G3
SYMPTOM

Discharge air temperature does not change.

PBR circuit is open or shorted.
DIAGNOSIS PROCEDURE FOR AIR MIX DOOR MOTOR PBR
Perform diagnosis procedure. Refer to AT C - 5 9 , "DIAGNOSIS PROCEDURE FOR LAN CIRCUIT" .
RJIA3257E
RJIA3258E

ATC-70
TROUBLE DIAGNOSIS

SYSTEM DESCRIPTION
Component Parts
Intake door control system components are:

Unified meter and A/C amp.

Intake door motor (LCU)

A/C LAN system (PBR built-in mode door motor, air mix door motor and intake door motor)

In-vehicle sensor

Ambient sensor

Sunload sensor

Intake sensor
System Operation
The intake door control determines intake door position based on the ambient temperature, the intake air tem-
perature and the in-vehicle temperature. When the DEF or OFF switches are pressed or A/C switch is OFF,
the unified meter and A/C amp. sets the intake door at the FRE position.
Intake Door Control Specification
SJIA1651E
RJIA4067E

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ATC-71
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COMPONENT DESCRIPTION
Intake Door Motor
The intake door motor is attached to the blower unit. It rotates so that
air is drawn from inlets set by the unified meter and A/C amp. Motor
rotation is conveyed to a lever which activates the intake door.
DIAGNOSIS PROCEDURE FOR INTAKE DOOR MOTOR
SYMPTOM: Intake door motor does not operate normally.
Perform diagnosis procedure. Refer to AT C - 5 9 , "
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT" .
RJIA3260E

TROUBLE DIAGNOSIS
ATC-73
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SYSTEM DESCRIPTION
Component Parts
Fan speed control system components are:

Unified meter and A/C amp.

A/C LAN system (PBR built-in mode door motor, air mix door motor and intake motor)

Fan control amp.

In-vehicle sensor

Ambient sensor

Sunload sensor

Intake sensor
System Operation
Automatic Mode
In the automatic mode, the blower motor speed control signal is calculated by the unified meter and A/C amp.
based on the input from the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor.
The blower motor applied voltage ranges from approximately 3.5 volts (lowest speed) to 12 volts (highest
speed).
The control blower speed (in the range of 3.5 to 12 V), unified meter and A/C amp. supplies a gate voltage to
the fan control amp. Based on this voltage, fan control amp. controls voltage supplied to the blower motor.
Starting Fan Speed Control
Start up from COLD SOAK Condition (Automatic mode)
In a cold start up condition where the engine coolant temperature is below 56°C (133°F), the blower will not
operate for a short period of time (up to 150 seconds). The exact start delay time varies depending on the
ambient and engine coolant temperature.
In the most extreme case (very low ambient) the blower starting delay will be 150 seconds as described
above. After this delay, the blower will operate at low speed until the engine coolant temperature rises above
56°C (133°F), and then the blower speed will increase to the objective speed.
Start up from usual or HOT SOAK Condition (Automatic mode)
The blower will begin operation momentarily after the AUTO switch is pressed. The blower speed will gradu-
ally rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).
RJIA3262E

ATC-74
TROUBLE DIAGNOSIS

Blower Speed Compensation
Sunload
When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low
speed. The low speed will vary depending on the sunload. During conditions of low or no sunload, the blower
speed is low (approx. 3.5 V). During high sunload conditions, unified meter and A/C amp. raise the blower
speed (approx. 6.5 V).
Fan Speed Control Specification
COMPONENT DESCRIPTION
Fan Control Amp.
The fan control amp. is located on the blower unit. The fan control
amp. receives a gate voltage from unified meter and A/C amp. to
steplessly maintain the blower fan motor voltage in the 3.5 to 12 volt
range.
DIAGNOSIS PROCEDURE FOR BLOWER MOTOR
SYMPTOM: Blower motor operation is malfunctioning.
RJIA3263E
RJIA3264E
RJIA3265E

TROUBLE DIAGNOSIS
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1. CHECK POWER SUPPLY FOR BLOWER MOTOR
1. Disconnect blower motor connector.
2. Turn ignition switch ON.
3. Check voltage between blower motor harness connector M48
terminal 1 and ground.
OK or NG
OK >> GO TO 2.
NG >> Check power supply circuit and 15A fuses [Nos. 10 and
11, located in the fuse block (J/B)]. Refer to PG-79,
"FUSE BLOCK - JUNCTION BOX (J/B)" .

If fuses are OK, check harness for open circuit. Repair or replace if necessary.

If fuses are NG, check harness for short circuit and replace fuse.
2. CHECK FAN FEEDBACK CIRCUIT
1. Turn ignition switch OFF.
2. Reconnect blower motor connector.
3. Turn ignition switch ON.
4. Check voltage between unified meter and A/C amp. harness
connector M45 terminal 47 and ground.
OK or NG
OK >> GO TO 3.
NG >> GO TO 9.
3. CHECK BLOWER MOTOR
Check blower motor. Refer to AT C - 7 7 , "
Blower Motor" .
OK or NG
OK >> GO TO 4.
NG >> Replace blower motor.
4. CHECK POWER SUPPLY FOR FAN CONTROL AMP.
1. Turn ignition switch ON.
2. Check voltage between fan control amp. harness connector
M86 terminal 3 and ground.
OK or NG
OK >> GO TO 5.
NG >> Repair harness or connector.1 – Ground : Battery voltage
RJIA2860E
47 – Ground : Battery voltage.
RJIA3266E
Terminals
Condition Voltage (+)
(−)
Fan control
amp. connectorTe r m i n a l N o .
M86 3 GroundFan speed: 1st
speedApprox. 8 V
RJIA2862E

ATC-76
TROUBLE DIAGNOSIS

5. CHECK GROUND CIRCUIT FOR FAN CONTROL AMP.
1. Turn ignition switch OFF.
2. Disconnect fan control amp. connector.
3. Check continuity between fan control amp. harness connector
M86 terminal 1 and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.
6. CHECK FOR UNIFIED METER AND A/C AMP. OUTPUT SIGNAL
1. Reconnect fan control amp. connector.
2. Turn ignition switch ON.
3. Check voltage between fan control amp. harness connector
M86 terminal 2 and ground.
OK or NG
OK >> GO TO 9.
NG >>

If the voltage is lower than 2.5 V: GO TO 7.

If the voltage is higher than 10.5 V: GO TO 8.
7. CHECK CIRCUIT CONTINUITY BETWEEN UNIFIED METER AND A/C AMP. AND FAN CONTROL
AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector and fan con-
trol amp. connector.
3. Check continuity between unified meter and A/C amp. harness
connector M45 terminal 60 and fan control amp. harness con-
nector M86 terminal 2.
OK or NG
OK >> Replace fan control amp.
NG >> Repair harness or connector.1 – Ground : Continuity should exist.
RJIA2863E
Terminals
Condition Voltage (+) (−)
Fan control
amp. connectorTerminal No.
M86 2 GroundFan speed: 1st -
4th speedApprox. 2.5 -
3.5 V
Fan speed: 5th
speedApprox. 9.5 -
10.5 V
RJIA2864E
60 – 2 : Continuity should exist.
RJIA3267E

TROUBLE DIAGNOSIS
ATC-77
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8. CHECK FAN CONTROL AMP.
1. Turn ignition switch OFF.
2. Disconnect fan control amp. connector.
3. Check continuity between fan control amp. connector M86 ter-
minal 2 and 1.
OK or NG
OK >> GO TO 9.
NG >> Replace fan control amp.
9. CHECK CIRCUIT CONTINUITY BETWEEN UNIFIED METER AND A/C AMP. AND FAN CONTROL
AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector.
3. Check continuity between unified meter and A/C amp. harness
connector M45 terminal 47 and fan control amp. harness con-
nector M86 terminal 3.
OK or NG
OK >> Replace unified meter and A/C amp.
NG >> Repair harness or connector.
COMPONENT INSPECTION
Blower Motor
Confirm smooth rotation of the blower motor.

Ensure that there are no foreign particles inside the blower unit.2 – 1 : Continuity should exist.
SJIA0476E
47 – 3 : Continuity should exist.
RJIA3268E
RJIA3269E