2008 INFINITI QX56 battery volt

GI-44
< BASIC INSPECTION >
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
Note in the illustration that there is an excessive 4.1 volt drop between the battery and the bulb.
Measuring Voltage Drop — Steb-by-Step
• The step-by-step method is most useful for isolating excessive drops in low voltage systems (such as those
in “Computer Controlled Systems”).
• Circuits in the “Computer Controlled System” operate on very low amperage.
• The (Computer Controlled) system oper ations can be adversely affected by any variation in resistance in the
system. Such resistance variation may be caused by poor connection, improper installation, improper wire
gauge or corrosion.
• The step by step voltage drop test can identify a component or wire with too much resistance.
CONTROL UNIT CIRCUIT TEST
System Description
• When the switch is ON, the control unit lights up the lamp.
CASE 1
SGI974
SAIA0258E
MGI034A
Revision: March 2010 2008 QX56

SERVICE INFORMATION FOR ELECTRICAL INCIDENTGI-45
< BASIC INSPECTION >
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INPUT-OUTPUT VOLTAGE CHART
• The voltage value is based on the body ground.
• *: If high resistance exists in the switch side circuit (caused by a single strand), terminal 1 does not detect battery voltag e. Control unit
does not detect the switch is ON even if the switch does not turn ON. Therefore, the control unit does not supply power to ligh t up the
lamp.
CASE 2
INPUT-OUTPUT VOLTAGE CHART
• The voltage value is based on the body ground.
• *: If high resistance exists in the switch side circuit (caused by a single strand), terminal 2 does not detect approx. 0V. Co ntrol unit
does not detect the switch is ON even if the switch does not turn ON. Therefore, the control unit does not control ground to li ght up the
lamp. Terminal No. Description
Condition Value (Approx.)In case of high resistance such as single
strand (V) *
+ −Signal name Input/
Output
1 Body
ground Switch Input Switch ON
Battery voltageLower than battery voltage Approx. 8 (Ex-
ample)
Switch OFF 0 V Approx. 0
2 Body
ground Lamp Output Switch ON
Battery voltage App rox. 0 (Inoperative lamp)
Switch OFF 0 V Approx. 0
Terminal No. Description
Condition Value (Approx.)In case of high resistance such as single
strand (V) *
+ −Signal name Input/
Output
1 Body
ground Lamp Output Switch ON
0VBattery voltage (Inoperative lamp)
Switch OFF Battery voltage Battery voltage
2 Body
ground Switch Input Switch ON
0 V Higher than 0 Approx. 4 (Example)
Switch OFF 5 V Approx. 5
MGI035A
Revision: March 2010 2008 QX56

HAC-20
< FUNCTION DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
DIAGNOSIS SYSTEM (HVAC)
DIAGNOSIS SYSTEM (HVAC)
CONSULT-III Function (HVAC)INFOID:0000000001679777
CONSULT-III can display each diagnostic item using the diagnostic test modes shown following.
SELF-DIAGNOSIS
Display Item List
DATA MONITOR
Display Item List
Diagnostic mode
Description
SELF-DIAG RESULTS Displays A/C au to amp. self-diagnosis results.
DATA MONITOR Displays A/C auto amp. input/output data in real time.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read. ECU PART NUMBER A/C auto amp. part number can be read.
DTC Description
Reference page
B2573 Battery voltage out of range CHG-10, "
Inspection Procedure"
B2578 In-vehicle sensor circuit out of range (low)
HAC-81, "In-Vehicle Sensor Diagnosis Procedure"B2579 In-vehicle sensor circuit out of range (high)
B257B Ambient sensor circuit short HAC-78, "
Ambient Sensor Diagnosis Procedure"B257C Ambient sensor circuit open
B257F Optical sensor (Driver) circuit open or short HAC-84, "
Optical Sensor Diagnosis Procedure".
B2580 Optical sensor (Passenger) circuit open or short
B2581 Intake sensor circuit short HAC-86, "
Intake Sensor Diagnosis Procedure"B2582 Intake sensor circuit open
U1000 CAN bus fault LAN-14, "
Trouble Diagnosis Flow Chart"
Monitor itemValue Contents
BATT VIA CAN "V" Displays battery voltage signal.
IGN VIA CAN "ON/OFF" Displays ignition switch signal.
DVR SUNLD SEN "w/m2" Displays optical sensor (driver) signal.
PAS SUNLD SEN "w/m2" Displays optical sensor (passenger) signal.
AMB TEMP SEN "° C" Displays ambient sensor signal.
EVAP TEMP SEN "° C" Displays intake sensor signal.
INCAR TMP SEN "° C" Displays in-vehicle sensor signal.
RR TEMPSET FR "V" Displays air mix door (front) set point signal.
RR TEMPSET RR "V" Displays air mix door (rear) set point signal.
MODE FDBCK "V" Displays mode door motor feedback signal.
DVR MIX FDBCK "V" Displays air mix door motor (driver) feedback signal.
PAS MIX FDBCK "V" Displays air mix door motor (passenger) feedback signal.
RR FDBCK "V" Displays air mix door motor (rear) feedback signal.
DEF FDBCK "V" Displays defroster door motor feedback signal.
Revision: March 2010 2008 QX56

HAC-22
< FUNCTION DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
SELF-DIAGNOSIS FUNCTION
SELF-DIAGNOSIS FUNCTION
A/C Auto Amp. Self-DiagnosisINFOID:0000000001679779
A/C SYSTEM SELF-DIAGNOSIS FUNCTION
The self-diagnosis function is built into the A/C aut
o amp. to quickly locate the cause of malfunctions.
DESCRIPTION
The self-diagnostic system diagnoses sensors, CAN sys tem, and battery voltage on A/C auto amp. Refer to
applicable sections (items) for details. Fault codes (if any are present) will be displayed in the ambient temper-
ature display area. Refer to HAC-23, "
A/C System Self-Diagnosis Code Chart".
SELF-DIAGNOSTIC MODE
NOTE:
Radio must be off.
1. On the A/C and AV switch asse mbly, press the "SETTING" but-
ton and twist the volume knob clockwise and counterclockwise
until the Self-Diagnosis screen shows on the display.
2. Scroll down to "Confirmation/Adjustment" and press the "ENTER" button.
3. Scroll down to "Climate Control" and press the "ENTER" button.
4. The fan bars will flash on the display during the self-test, and then the fault codes will display in the ambient temperature area.
They will continue scrolling until diagnostic mode is exited.
5. Exit by pressing the "BACK" button on A/C and AV switch assembly until display returns to its normal operation screen.
HVAC system will be OFF.
The self-diagnostic system diagnoses sensors, CAN sys tem, and battery voltage on A/C auto amp. Refer to
applicable sections (items) for details. Fault codes (if any are present) will be displayed in the ambient temper-
ature display area. Refer to HAC-23, "
A/C System Self-Diagnosis Code Chart".
A/C and AV Switch Asse mbly Self-DiagnosisINFOID:0000000001679780
A/C and AV switch assembly self-diagnosis function
The ON/OFF operation (continuity) of each switch in the A/C and AV switch assembly can be checked.
Self-diagnosis mode
AWNIA0098ZZ
AWIIA0081ZZ
Revision: March 2010 2008 QX56

SELF-DIAGNOSIS FUNCTIONHAC-23
< FUNCTION DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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• Press the “BACK” switch and the “UP” switch within 10 seconds after turning the ignition switch from OFF to ACC and hold them for
3 seconds or more. Then the buzzer sounds, all indicators of the
preset switch illuminate, and the self-diagnosis mode starts.
• The continuity of each switch and control dials (A/C and AV switch assembly only) at the ON position can be checked by pressing
each switch and turning each control dial. The buzzer sounds and
LED’s will illuminate if the switch is normal.
Finishing self-diagnosis mode
Self-diagnosis mode is canceled when turning the ignition switch OFF.
A/C System Self-Diagnosis Code ChartINFOID:0000000001679781
SELF-DIAGNOSTIC CODE CHART
AWIIA0171GB
Code No. Reference page
03 Battery voltage out of range CHG-11, "
Inspection Procedure"
30 In-vehicle sensor circuit out of range (low)
HAC-81, "In-Vehicle Sensor Diagnosis Procedure"31 In-vehicle sensor circuit out of range (high)
40 Ambient sensor circuit shortHAC-78, "
Ambient Sensor Diagnosis Procedure"41 Ambient sensor circuit open
50 Optical sensor (Driver) circuit open or shortHAC-84, "
Optical Sensor Diagnosis Procedure"52 Optical sensor (Passenger) circuit open or short
56 Intake sensor circuit shortHAC-86, "
Intake Sensor Diagnosis Procedure"57 Intake sensor circuit open
80 CAN bus faultLAN-14, "
Trouble Diagnosis Flow Chart"
Revision: March 2010 2008 QX56

HAC-26
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
MODE DOOR MOTOR
7.CHECK THE MODE DOOR MO
TOR (FRONT) PBR CIRCUIT
Perform diagnostic procedure for the mode door motor (front). Refer to HAC-25, "
Mode Door Motor (Front)
Component Function Check".
Is the inspection result normal?
YES >> GO TO 8.
NO >> Repair PBR circuit or replace motor. Refer to HAC-26, "
Mode Door Motor (Front) Diagnosis Pro-
cedure".
8.RECHECK FOR CODES
Perform A/C auto amp. self-diagnosis. Refer to HAC-22, "
A/C Auto Amp. Self-Diagnosis".
Are any self-diagnostic codes present?
YES >> Refer to HAC-23, "A/C System Self-Diagnosis Code Chart".
NO >> GO TO 9.
9.RECHECK FOR SYMPTOMS
Perform a complete operational check and check for any symptoms. Refer to HAC-4, "
Operational Check
(Front)".
Does another symptom exist?
YES >> Repair as necessary.
NO >> Replace A/C auto amp. Refer to VTL-7, "
Removal and Installation".
Mode Door Motor (Front) Diagnosis ProcedureINFOID:0000000001679784
SYMPTOM:
• Air outlet does not change.
• Mode door motor does not operate normally.
1.CHECK A/C AUTO AMP. FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Press the mode switch to the B/L ( ) mode.
3. Check voltage between A/C auto amp. harness connector M49 terminal 19 and terminal 20 while pressing the mode switch to
the floor ( ) mode.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK MODE DOOR MOTOR CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector M49 terminal 19, 20 and ground.
Is the inspection result normal?
YES >> Replace A/C auto amp. Refer to VTL-7, "Removal and
Installation".
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
A/C auto amp.: M49 20
19Press
mode
switch Battery
voltage
AWIIA0095ZZ
19 - Ground : Continuity should not exist.
20 - Ground : Continuity should not exist.
AWIIA0096ZZ
Revision: March 2010 2008 QX56

MODE DOOR MOTORHAC-27
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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NO >> Repair or replace harness as necessary.
3.CHECK A/C AUTO AMP. FOR GROUND AND POWER
1. Press the mode switch to the D/F ( ) mode.
2. Check voltage between A/C auto amp. harness connector M49 terminal 19 and terminal 20 while pressing the mode switch to
the vent ( ) mode.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Replace A/C auto amp. Refer to VTL-7, "
Removal and Installation".
4.CHECK MODE DOOR MOTOR AND CIRCUITS FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector M49 terminal 19 and terminal 20.
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 5.
5.CHECK MODE DOOR MOTOR CIRCUITS FOR OPEN
1. Disconnect the mode door motor harness connector.
2. Check continuity between A/C auto amp. harness connector M49 (A) terminal 19, 20 and the mode door motor harness con-
nector M142 (B) terminal 5, 6.
Is the inspection result normal?
YES >> Replace mode door motor. Refer to VTL-24, "Removal
and Installation".
NO >> Repair or replace harness as necessary.
6.CHECK A/C AUTO AMP. FOR PBR POWER AND GROUND
1. Reconnect A/C auto amp. harness connector.
2. Turn ignition switch ON.
3. Check voltage between A/C auto amp. harness connector M50 (A) terminal 28 and M49 (B) terminal 3.
Is the inspection result normal?
YES >> GO TO 8.
NO >> GO TO 7.
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
A/C auto amp.: M49 19 20 Press
mode
switch Battery
voltage
AWIIA0097ZZ
Continuity should exist.
AWIIA0098ZZ
5 - 19 : Continuity should exist.
6 - 20 : Continuity should exist.
AWIIA0094ZZ
Connector Te r m i n a l s
Voltage (Ap-
prox.)
(+) (-)
A/C auto amp.: M49, M50 28 35V
AWIIA0099ZZ
Revision: March 2010 2008 QX56

AIR MIX DOOR MOTORHAC-33
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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1. Turn ignition switch ON.
2. Rotate temperature control dial (driver) to 32 °C (90 °F).
3. Check voltage between A/C auto amp. harness connector M49
terminal 17 and terminal 18 while rotating temperature control
dial (driver) to 18 °C (60° F).
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK AIR MIX DOOR MOTOR (DRIVER) CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector M49 terminal 17, 18 and ground.
Is the inspection result normal?
YES >> Replace A/C auto amp. Refer to VTL-7, "Removal and
Installation".
NO >> Repair or replace harness as necessary.
3.CHECK A/C AUTO AMP. FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (driver) to 32 °C (90 °F).
3. Check voltage between A/C auto amp. harness connector M49
terminal 17 and terminal 18 while rotating temperature control
dial (driver) to 18 °C (60° F).
Is the inspection result normal?
YES >> GO TO 4.
NO >> Replace A/C auto amp. Refer to VTL-7, "
Removal and Installation".
4.CHECK AIR MIX DOOR MOTOR (DRIVER) CIRCUITS FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector M49 terminal 17 and terminal 18.
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 5.
5.CHECK AIR MIX DOOR MOTOR (DRIVER) CIRCUITS FOR OPEN
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
A/C auto amp.: M49 17 18 Rotate temp
control dial Battery
voltage
AWIIA0112ZZ
17 - Ground : Continuity should not exist.
18 - Ground : Continuity should not exist.
AWIIA0114ZZ
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
A/C auto amp.: M49 18 17
Rotate temp
control dial Battery
voltage
AWIIA0115ZZ
Continuity should exist.
AWIIA0116ZZ
Revision: March 2010 2008 QX56