Page 73 of 142
TROUBLE DIAGNOSIS
ATC-73
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AT C
Revision: 2006 November2007 350Z
4. CHECK UNIFIED METER AND A/C AMP. OUTPUT SIGNAL
1. Reconnect blower motor connector and unified meter and A/C
amp. connector.
2. Turn ignition switch ON.
3. Change the fan speed from Lo to Hi, and check the duty ratios
between blower motor harness connector M62 terminal 2 and
ground by using an oscilloscope. Normal terminal 2 drive signal
duty ratios are shown in the table below.
OK or NG
OK >> Replace blower motor after confirming the fan air flow does not change.
NG >> Replace unified meter and A/C amp.
COMPONENT INSPECTION
Blower Motor
Confirm smooth rotation of the blower motor.
Ensure that there are no foreign particles inside the blower unit.
RJIA2000E
RJIA1390E
RJIA0905E
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ATC-74
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
Magnet Clutch CircuitNJS00015
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
*1ATC-46, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 1.*2ATC-92, "
Ambient Sensor Circuit"*3AT C - 4 6 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 9.
*4ATC-75, "
DIAGNOSIS PROCE-
DURE FOR MAGNET CLUTCH"
*5ATC-86, "TROUBLE DIAGNOSIS
FOR UNUSUAL PRESSURE"
*6AT C - 5 3 , "Operational Check"
*7ATC-46, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 5 to 7.*8ATC-34, "
SYMPTOM TABLE"*9ATC-100, "Intake Sensor Circuit"
SJIA1129E
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TROUBLE DIAGNOSIS
ATC-75
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Revision: 2006 November2007 350Z
SYSTEM DESCRIPTION
Unified meter and A/C amp. controls compressor operation by ambient temperature, intake air temperature
and signal from ECM.
Low Temperature Protection Control
Unified meter and A/C amp. will turn compressor ON or OFF as determined by a signal detected by ambient
sensor and intake sensor.
When ambient temperature is higher than −2°C (28°F), the compres-
sor turns ON. The compressor turns OFF when ambient temperature
is lower than −5°C (23°F).
When intake air temperature is higher than 1°C (34°F), the compres-
sor turns ON. The compressor turns OFF when intake air tempera-
ture is lower than −5°C (23°F).
DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
RHA094GB
SJIA0267E
SJIA1891E
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ATC-76
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
1. CHECK AMBIENT SENSOR CIRCUIT AND INTAKE SENSOR CIRCUIT
Check ambient sensor and intake sensor. Refer to AT C - 4 6 , "
FUNCTION CONFIRMATION PROCEDURE" ,
see No. 9.
OK or NG
OK >> GO TO 2.
NG >>
Malfunctioning ambient sensor: Refer to AT C - 9 2 , "Ambient Sensor Circuit" .
Malfunctioning intake sensor: Refer to ATC-100, "Intake Sensor Circuit" .
2. PERFORM AUTO ACTIVE TEST
Refer to PG-20, "
Auto Active Test" .
Dose the magnet clutch operate?
YES >> WITH CONSULT-III: GO TO 5.
WITHOUT CONSULT-III: GO TO 6.
NO >> Check 10A fuse (No. 79, located in IPDM E/R), and GO TO 3. Refer to PG-23, "
IPDM E/R Termi-
nal Arrangement" .
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 F24 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 6 , "
FUNCTION
CONFIRMATION PROCEDURE" and preform self-
diagnosis STEP-4. Confirm that magnet clutch opera-
tion normal.
NG >> 1. Replace magnet clutch.
2. Go to self-diagnosis procedure AT C - 4 6 , "
FUNCTION
CONFIRMATION PROCEDURE" and preform 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 3 , "
CONSULT-III Function (BCM)" .
OK or NG
OK >> GO TO 8.
NG >> GO TO 6.
33 – 1 : Continuity should exist.
RJIA2004E
RJIA2005E
A/C SW ON : AIR COND SIG ON
A/C SW OFF : AIR COND SIG OFF
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TROUBLE DIAGNOSIS
ATC-77
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Revision: 2006 November2007 350Z
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 M90 terminal
27 and unified meter and A/C amp. harness connector M50 ter-
minal 42.
OK or NG
OK >> GO TO 7.
NG >> Repair harness or connector.
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 M50 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.27 – 42 : Continuity should exist.
RJIA2006E
Terminals
Condition Voltage (+)
(−) Unified meter
and A/C amp.
connectorTerminal No.
M50 42 GroundA/C switch: ON
(Blower motor oper-
ates.)Approx. 0 V
A/C switch: OFF Approx. 5 V
RJIA2007E
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ATC-78
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
8. CHECK REFRIGERANT PRESSURE SENSOR
WITH CONSULT-III
1. Start the engine.
2. Check voltage of refrigerant pressure sensor. Refer to EC-127, "
CONSULT-III Reference Value in Data
Monitor" .
WITHOUT CONSULT-III
1. Start the engine.
2. Check voltage between ECM harness connector M71 terminal 105 and ground.
OK or NG
OK >> WITH CONSULT-III: GO TO 9.
WITHOUT CONSULT-III: GO TO 10.
NG >> Refer to EC-710, "
REFRIGERANT PRESSURE SENSOR" .
9. CHECK BCM INPUT (FAN ON) SIGNAL
Check FAN ON/OFF signal. Refer to AT C - 3 3 , "
CONSULT-III 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 M90 terminal
28 and unified meter and A/C amp. harness connector M50 ter-
minal 57.
OK or NG
OK >> GO TO 11.
NG >> Repair harness or connector.
Terminals
Condition Voltage (+)
(−)
ECM con-
nectorTerminal No.
M71 105 GroundA/C switch: ON
(Blower motor
operates.)Approx. 1.0 - 4.0 V
FAN SW ON : HEATER FAN SW ON
FAN SW OFF : HEATER FAN SW OFF
28 – 57 : Continuity should exist.
RJIA2009E
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TROUBLE DIAGNOSIS
ATC-79
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Revision: 2006 November2007 350Z
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 M50 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.
12. CHECK CAN COMMUNICATION
Check CAN communication. Refer to BCS-16, "
CAN Communication Inspection Using CONSULT-III (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).
Terminals
Condition Voltage (+)
(−) Unified meter
and A/C amp.
connectorTerminal No.
M50 57 GroundFan control dial: ON
(Blower motor oper-
ates.)Approx. 0 V
Fan control dial: OFF Approx. 5 V
RJIA2010E
Page 80 of 142
ATC-80
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
COMPONENT INSPECTION
Refrigerant Pressure Sensor
The refrigerant pressure sensor is attached to the liquid tank.
Make sure that the A/C refrigerant pressure and the sensor output
voltage are within the specified range as shown in the A/C operating
condition figure. Refer to EC-710, "
REFRIGERANT PRESSURE
SENSOR" .
RJIA1393E
SJIA1841E