Unified NISSAN TEANA 2003 Owner's Guide

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ATC-79
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SYSTEM DESCRIPTION
Unified meter and A/C amp. controls compressor operation by intake air temperature and signal from ECM.
Low Temperature Protection Control
Unified meter and A/C amp. will turn the compressor ON or OFF as determined by a signal detected by intake
sensor.
When intake air temperature is higher than 4°C (39°F), the compres-
sor turns ON. The compressor turns OFF when intake air tempera-
ture is lower than 2.5°C (37°F).
DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
1. CHECK INTAKE SENSOR CIRCUIT
Check intake sensor. Refer to AT C - 4 7 , "
FUNCTION CONFIRMATION PROCEDURE" , see No. 11.
OK or NG
OK >> GO TO 2.
NG >> Malfunctioning intake sensor: Refer to ATC-105, "
Intake Sensor Circuit" .
2. PERFORM AUTO ACTIVE TEST
Refer to PG-21, "
Auto Active Test" .
Does the magnet clutch operate?
YES >>
WITH CONSULT-II: GO TO 5.

WITHOUT CONSULT-II: GO TO 6.
NO >> Check 10 A fuse (No. 79, located in IPDM E/R). Refer to PG-25, "
IPDM E/R Terminal Arrange-
ment" , and GO TO 3.
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ATC-80
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3. CHECK CIRCUIT CONTINUITY BETWEEN IPDM E/R AND COMPRESSOR
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R connector and compressor connector.
3. Check continuity between IPDM E/R harness connector E8 ter-
minal 33 and compressor harness connector F2 terminal 1.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK MAGNET CLUTCH CIRCUIT
Check for operation sound when applying battery voltage direct cur-
rent to terminal.
OK or NG
OK >> 1. Replace IPDM E/R.
2. Go to self-diagnosis procedure AT C - 4 7 , "
FUNCTION
CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-4. Confirm that magnet clutch opera-
tion normal.
NG >> 1. Replace compressor. Refer to ATC-134, "
Removal
and Installation of Compressor" .
2. Go to self-diagnosis procedure AT C - 4 7 , "
FUNCTION
CONFIRMATION PROCEDURE" and perform self-diagnosis STEP-4. Confirm that magnet
clutch operation normal.
5. CHECK BCM INPUT (COMPRESSOR ON) SIGNAL
Check compressor ON/OFF signal. Refer to AT C - 3 4 , "
CONSULT-II
Function (BCM)" .
OK or NG
OK >> GO TO 8.
NG >> GO TO 6.
6. CHECK CIRCUIT CONTINUITY BETWEEN BCM AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect BCM connector and unified meter and A/C amp.
connector.
3. Check continuity between BCM harness connector M3 terminal
27 and unified meter and A/C amp. harness connector M45 ter-
minal 42.
OK or NG
OK >> GO TO 7.
NG >> Repair harness or connector.33 – 1 : Continuity should exist.
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A/C SW ON : AIR COND SW ON
A/C SW OFF : AIR COND SW OFF
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27 – 42 : Continuity should exist.
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ATC-81
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7. CHECK VOLTAGE FOR UNIFIED METER AND A/C AMP. (COMPRESSOR ON SIGNAL)
1. Reconnect BCM connector and unified meter and A/C amp.
connector.
2. Turn ignition switch ON.
3. Check voltage between unified meter and A/C amp. harness
connector M45 terminal 42 and ground.
OK or NG
OK >> GO TO 8.
NG-1 >> If the voltage is approx. 5 V when A/C switch is ON: Replace unified meter and A/C amp.
NG-2 >> If the voltage is approx. 0 V when A/C switch is OFF: Replace BCM.
8. CHECK REFRIGERANT PRESSURE SENSOR
WITH CONSULT-II
1. Start the engine.
2. Check voltage of refrigerant pressure sensor. Refer to EC-90,
"CONSULT-II Reference Value in Data Monitor Mode" (QR
engine) or EC-434, "
CONSULT-II Reference Value in Data Mon-
itor Mode" (VQ engine).
WITHOUT CONSULT-II
1. Start the engine.
2. Check voltage between ECM harness connector F101 terminal
70 and ground.
OK or NG
OK >>
WITH CONSULT-II: GO TO 9.

WITHOUT CONSULT-II: GO TO 10.
NG >> Refer to EC-339, "
REFRIGERANT PRESSURE SENSOR" (QR engine) or EC-748, "REFRIGER-
ANT PRESSURE SENSOR" (VQ engine).
Te r m i n a l s
Condition Voltage (+)
(-) Unified meter
and A/C amp.
connectorTerminal
No.
M45 42 GroundA/C switch: ON
(Blower motor oper-
ates.)Approx. 0 V
OFF switch: ON (A/C
System: OFF)Approx. 5 V
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Terminals
Condition Voltage (+)
(-)
ECM con-
nectorTerminal No.
F10169 (QR engine)
GroundA/C switch: ON
(Blower motor
operates.)Approx. 1.0 - 4.0 V
70 (VQ engine)
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ATC-82
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9. CHECK BCM INPUT (FAN ON) SIGNAL
Check FAN ON/OFF signal. Refer to AT C - 3 4 , "
CONSULT-II Function
(BCM)" .
OK or NG
OK >> GO TO 12.
NG >> GO TO 10.
10. CHECK CIRCUIT CONTINUITY BETWEEN BCM AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect BCM connector and unified meter and A/C amp.
connector.
3. Check continuity between BCM harness connector M3 terminal
28 and unified meter and A/C amp. harness connector M45 ter-
minal 57.
OK or NG
OK >> GO TO 11.
NG >> Repair harness or connector.
11 . CHECK VOLTAGE FOR UNIFIED METER AND A/C AMP. (FAN ON SIGNAL)
1. Reconnect BCM connector and unified meter and A/C amp.
connector.
2. Turn ignition switch ON.
3. Check voltage between unified meter and A/C amp. harness
connector M45 terminal 57 and ground.
OK or NG
OK >> GO TO 12.
NG-1 >> If the voltage is approx. 5 V when blower motor is ON: Replace unified meter and A/C amp.
NG-2 >> If the voltage is approx. 0 V when blower motor is OFF: Replace BCM.FAN CONTROL SW ON : FAN ON SIG ON
FAN CONTROL SW OFF : FAN ON SIG OFF
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28 – 57 : Continuity should exist.
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Terminals
Condition Voltage (+)
(-) Unified meter
and A/C amp.
connectorTerminal No.
M45 57 GroundAUTO switch: ON
(Blower motor
operates.)Approx. 0 V
OFF switch: ON
(A/C system: OFF)Approx. 5 V
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ATC-83
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12. CHECK CAN COMMUNICATION
Check CAN communication. Refer to BCS-14, "
CAN Communication Inspection Using CONSULT-II (Self-
Diagnosis)" .

BCM – ECM

ECM – IPDM E/R

ECM – Unified meter and A/C amp.
OK or NG
OK >> Replace ECM.
NG >> Repair or replace malfunctioning part(s).
COMPONENT INSPECTION
Refrigerant Pressure Sensor
The refrigerant pressure sensor is attached to the condenser.
Make sure that the A/C refrigerant pressure and the sensor output
voltage are as shown in the A/C operating condition figure. Refer to
EC-339, "
REFRIGERANT PRESSURE SENSOR" (QR engine) or
EC-748, "
REFRIGERANT PRESSURE SENSOR" (VQ engine).
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ATC-96
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Ambient Sensor CircuitBJS000GC
COMPONENT DESCRIPTION
Ambient Sensor
The ambient sensor is attached on the hood lock stay. It detects
ambient temperature and converts it into a resistance value which is
then input into the unified meter and A/C amp.
AMBIENT TEMPERATURE INPUT PROCESS
The unified meter and A/C amp. includes a processing circuit for the ambient sensor input. However, when the
temperature detected by the ambient sensor increases quickly, the processing circuit retards the unified meter
and A/C amp. function. It only allows the unified meter and A/C amp. to recognize an ambient temperature
increase of 0.33°C (0.6°F) per 100 seconds.
As an example, consider stopping for a few minutes after high speed driving. Although the actual ambient tem-
perature has not changed, the temperature detected by the ambient sensor will increase. This is because the
heat from the engine compartment can radiate to the front grille area, location of the ambient sensor.
DIAGNOSIS PROCEDURE FOR AMBIENT SENSOR
SYMPTOM: Ambient sensor circuit is open or shorted. (21 or − 21 is
indicated on unified meter and A/C amp. as a result of performing
self-diagnosis STEP-2.)
1. CHECK VOLTAGE BETWEEN AMBIENT SENSOR AND GROUND
1. Disconnect ambient sensor connector.
2. Turn ignition switch ON.
3. Check voltage between ambient sensor harness connector
E257 terminal 1 and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 4.
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1 – Ground : Approx. 5 V
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TROUBLE DIAGNOSIS
ATC-97
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2. CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector.
3. Check continuity between ambient sensor harness connector
E257 terminal 2 and unified meter and A/C amp. harness con-
nector M45 terminal 49.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3. CHECK AMBIENT SENSOR
Refer to AT C - 9 8 , "
Ambient Sensor" .
OK or NG
OK >> 1. Replace unified meter and A/C amp.
2. Go to self-diagnosis AT C - 4 7 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
NG >> 1. Replace ambient sensor.
2. Go to self-diagnosis AT C - 4 7 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
4. CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector.
3. Check continuity between ambient sensor harness connector
E257 terminal 1 and unified meter and A/C amp. harness con-
nector M45 terminal 39.
4. Check continuity between ambient sensor harness connector
E257 terminal 1 and ground.
OK or NG
OK >> 1. Replace unified meter and A/C amp.
2. Go to self-diagnosis AT C - 4 7 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
NG >> Repair harness or connector.2 – 49 : Continuity should exist.
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1 – 39 : Continuity should exist.
1 – Ground : Continuity should not exist.
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ATC-99
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In-vehicle Sensor CircuitBJS000GD
COMPONENT DESCRIPTION
In-vehicle Sensor
The in-vehicle sensor is located on instrument driver lower panel. It
converts variations in temperature of compartment air drawn from
the aspirator into a resistance value. It is then input into the unified
meter and A/C amp.
Aspirator
The aspirator is located on driver’s side of heater & cooling unit
assembly. It produces vacuum pressure due to air discharged from
the heater & cooling unit assembly, continuously taking compartment
air in the aspirator.
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ATC-100
TROUBLE DIAGNOSIS

DIAGNOSIS PROCEDURE FOR IN-VEHICLE SENSOR
SYMPTOM: In-vehicle sensor circuit is open or shorted. (22 or −22 is
indicated on unified meter and A/C amp. as a result of performing
self-diagnosis STEP-2.)
1. CHECK VOLTAGE BETWEEN IN-VEHICLE SENSOR AND GROUND
1. Disconnect in-vehicle sensor connector.
2. Turn ignition switch ON.
3. Check voltage between in-vehicle sensor harness connector
M29 terminal 1 and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 4.
2. CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR AND UNIFIED METER AND A/C
AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector.
3. Check continuity between in-vehicle sensor harness connector
M29 terminal 2 and unified meter and A/C amp. harness con-
nector M45 terminal 49.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3. CHECK IN-VEHICLE SENSOR
Refer to ATC-101, "
In-vehicle Sensor" .
OK or NG
OK >> 1. Replace unified meter and A/C amp.
2. Go to self-diagnosis AT C - 4 7 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
NG >> 1. Replace in-vehicle sensor.
2. Go to self-diagnosis AT C - 4 7 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
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1 – Ground : Approx. 5 V
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2 – 49 : Continuity should exist.
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ATC-101
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4. CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR AND UNIFIED METER AND A/C
AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector.
3. Check continuity between in-vehicle sensor harness connector
M29 terminal 1 and unified meter and A/C amp. harness con-
nector M45 terminal 40.
4. Check continuity between in-vehicle sensor harness connector
M29 terminal 1 and ground.
OK or NG
OK >> 1. Replace unified meter and A/C amp.
2. Go to self-diagnosis AT C - 4 7 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
NG >> Repair harness or connector.
COMPONENT INSPECTION
In-vehicle Sensor
After disconnecting in-vehicle sensor connector M29, measure resis-
tance between terminals 1 and 2 at sensor side. Refer to the table
below.
If NG, replace in-vehicle sensor.1 – 40 : Continuity should exist.
1 – Ground : Continuity should not exist.
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Temperature °C (°F) Resistance kΩ
−15 (5) 12.73
−10 (14) 9.92
−5 (23) 7.80
0 (32) 6.19
5 (41) 4.95
10 (50) 3.99
15 (59) 3.24
20 (68) 2.65
25 (77) 2.19
30 (86) 1.81
35 (95) 1.51
40 (104) 1.27
45 (113) 1.07
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