Ins INFINITI QX56 2004 Factory Service Manual

REFRIGERANT PRESSURE SENSOR
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Revision: August 20072004 QX56
REFRIGERANT PRESSURE SENSORPFP:92136
Component DescriptionUBS00HDH
The refrigerant pressure sensor is installed at the liquid tank of the
air conditioner system. The sensor uses an electrostatic volume
pressure transducer to convert refrigerant pressure to voltage. The
voltage signal is sent to ECM, and ECM controls cooling fan system.
BBIA0445E
SEF 0 99 XA

REFRIGERANT PRESSURE SENSOR
EC-609
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Revision: August 20072004 QX56
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
Diagnostic ProcedureUBS00HDJ
1. CHECK REFRIGERANT PRESSURE SENSOR OVERALL FUNCTION
1. Start engine and warm it up to normal operating temperature.
2. Turn A/C switch and blower switch ON.
3. Check voltage between ECM terminal 70 and ground with CON-
SULT-II or tester.
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
49 R/YSensor power supply
(Refrigerant pressure sen-
sor)[Ignition switch: ON]Approximately 5V
67 B Sensor ground[Engine is running]

Warm-up condition

Idle speedApproximately 0V
70 B/W Refrigerant pressure sensor[Engine is running]

Warm-up condition

Both A/C switch and blower switch are ON.
(Compressor operates.)1.0 - 4.0V
Voltage: 1.0 - 4.0V
PBIB11 88 E

REFRIGERANT PRESSURE SENSOR
EC-611
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Revision: August 20072004 QX56
6. CHECK REFRIGERANT PRESSURE SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 70 and refrigerant pressure sensor terminal 2.
Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 8.
NG >> GO TO 7.
7. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors E5, F14

Harness for open or short between ECM and refrigerant pressure sensor
>> Repair open circuit or short to ground or short to power in harness or connectors.
8. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
OK or NG
OK >> Replace refrigerant pressure sensor.
NG >> Repair or replace.
Removal and InstallationUBS00HDK
REFRIGERANT PRESSURE SENSOR
Refer to ATC-173, "Removal and Installation for Refrigerant Pressure Sensor" . Continuity should exist.

EC-612Revision: August 2007
ELECTRICAL LOAD SIGNAL
2004 QX56
ELECTRICAL LOAD SIGNALPFP:25350
DescriptionUBS00HDL
The electrical load signal (Headlamp switch signal, rear window defogger switch signal, etc.) is transferred
through the CAN communication line from BCM to ECM via IPDM E/R.
CONSULT-II Reference Value in Data Monitor ModeUBS00HDM
Specification data are reference values.
Diagnostic ProcedureUBS00HDN
1. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-I
1. Turn ignition switch ON.
2. Connect CONSULT-II and select “DATA MONITOR” mode.
3. Select “LOAD SIGNAL” and check indication under the following
conditions.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-II
Check “LOAD SIGNAL” indication under the following conditions.
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
3. CHECK REAR WINDOW DEFOGGER SYSTEM
Refer to GW-78, "
REAR WINDOW DEFOGGER" .
>>INSPECTION END
4. CHECK HEADLAMP SYSTEM
Refer to LT- 6 , "
HEADLAMP (FOR USA)" , or LT-34, "HEADLAMP (FOR CANADA) - DAYTIME LIGHT SYS-
TEM -" .
>>INSPECTION END
MONITOR ITEM CONDITION SPECIFICATION
LOAD SIGNAL

Ignition switch: ONRear window defogger switch is ON
and/or lighting switch is in 2nd.ON
Rear window defogger switch is OFF
and lighting switch is OFF.OFF
Condition Indication
Rear window defogger switch ON ON
Rear window defogger switch OFF OFF
PBIB0103E
Condition Indication
Lighting switch ON at 2nd position ON
Lighting switch OFF OFF
PBIB0103E

EC-616Revision: August 2007
ICC BRAKE SWITCH
2004 QX56
2. CHECK OVERALL FUNCTION-II
With CONSULT-II
Check “BRAKE SW2” indication in “DATA MONITOR” mode.
Without CONSULT-II
Check voltage between ECM terminal 101 and ground under the fol-
lowing conditions.
OK or NG
OK >>INSPECTION END
NG >> GO TO 10.
3. CHECK DTC WITH ICC UNIT
Refer to ACS-26, "
TROUBLE DIAGNOSIS — GENERAL DESCRIPTION" .
OK or NG
OK >> GO TO 4.
NG >> Repair or replace.
CONDITION INDICATION
When brake pedal is fully released OFF
When brake pedal is slightly depressed ON
SEC0 13 D
CONDITION VOLTAGE
When brake pedal is fully released Approximately 0V
When brake pedal is slightly depressed Battery voltage
MBIB0060E

EC-618Revision: August 2007
ICC BRAKE SWITCH
2004 QX56
7. CHECK ICC BRAKE SWITCH INPUT SIGNAL CIRCUIT
1. Disconnect ECM harness connector.
2. Check harness continuity between ICC brake switch terminal 2 and ECM terminal 108.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 8.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
8. CHECK ICC BRAKE SWITCH
Refer to EC-532, "
Component Inspection" .
OK >> GO TO 9.
NG >> Replace ICC brake switch.
9. CHECK ICC BRAKE HOLD RELAY
Refer to EC-532, "
Component Inspection" .
OK or NG
OK >> GO TO 14.
NG >> Replace ICC brake hold relay.
10. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check voltage between stop lamp switch terminal 3 and ground
with CONSULT -II or tester.
OK or NG
OK >> GO TO 12.
NG >> GO TO 11.Continuity should exist.
BBIA0470E
Voltage: Battery voltage
PBIB2309E

ICC BRAKE SWITCH
EC-619
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Revision: August 20072004 QX56
11 . DETECT MALFUNCTIONING PART
Check the following.

Harness connectors M31, E152

Fuse block (J/B) connector M60

10A fuse

Harness for open or short between stop lamp switch and battery
>> Repair open circuit or short to ground or short to power in harness or connectors.
12. CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 101 and stop lamp switch terminal 4.
Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 13.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
13. CHECK STOP LAMP SWITCH
Refer to EC-532, "
Component Inspection"
OK or NG
OK >> GO TO 14.
NG >> Replace stop lamp switch.
14. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionUBS00HZE
ICC BRAKE SWITCH
1. Turn ignition switch OFF.
2. Disconnect ICC brake switch harness connector.
3. Check continuity between ICC brake switch terminals 1 and 2
under the following conditions.
If NG, adjust ICC brake switch installation, refer to BR-6,
"BRAKE PEDAL" , and perform step 3 again.
STOP LAMP SWITCH
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.Continuity should exist.
Condition Continuity
When brake pedal is fully released. Should exist.
When brake pedal is slightly depressed. Should not exist.
SEC0 23 D

EC-620Revision: August 2007
ICC BRAKE SWITCH
2004 QX56
3. Check continuity between stop lamp switch terminals 3 and 4
under the following conditions.
If NG, adjust stop lamp switch installation, refer to BR-6,
"BRAKE PEDAL" , and perform step 3 again.
ICC BRAKE HOLD RELAY
1. Apply 12V direct current between ICC brake hold relay terminals 1 and 2.
2. Check continuity between relay terminals 3 and 4, 6 and 7 under
the following conditions.
3. If NG, replace ICC brake hold relay.
Condition Continuity
When brake pedal is fully released. Should not exist.
When brake pedal is slightly depressed. Should exist.
PBIB2310E
Condition Between terminals Continuity
12V direct current supply
between terminals 1 and 23 and 4 Should not exist
6 and 7 Should exist
No current supply3 and 4 Should exist
6 and 7 Should not exist
MBIB0063E

EC-624Revision: August 2007
ASCD BRAKE SWITCH
2004 QX56
2. CHECK OVERALL FUNCTION-II
With CONSULT-II
Check “BRAKE SW2” indication in “DATA MONITOR” mode.
Without CONSULT-II
Check voltage between ECM terminal 101 and ground under the following conditions.
OK or NG
OK >>INSPECTION END
NG >> GO TO 7.
CONDITION INDICATION
When brake pedal is released OFF
When brake pedal is depressed ON
SEC0 13 D
CONDITION VOLTAGE
When brake pedal is released Approximately 0V
When brake pedal is depressed Battery voltage
PBIB1537E

ASCD BRAKE SWITCH
EC-625
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Revision: August 20072004 QX56
3. CHECK ASCD BRAKE SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ASCD brake switch harness connector.
3. Turn ignition switch ON.
4. Check voltage between ASCD brake switch terminal 1 and
ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors M31, 152

Fuse block (J/B) connector M4

10A fuse

Harness for open or short between ASCD brake switch and fuse
>> Repair open circuit or short to ground or short to power in harness or connectors.
5. CHECK ASCD BRAKE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 108 and ASCD brake switch terminal 2.
Refer to Wiring Diagram.
4. Also check harness for short to ground or short to power.
OK or NG
OK >> GO TO 6.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
6. CHECK ASCD BRAKE SWITCH
Refer to EC-627, "
Component Inspection"
OK or NG
OK >> GO TO 11.
NG >> Replace ASCD brake switch.
BBIA0373E
Voltage: Battery voltage
PBIB0857E
Continuity should exist.