2008 INFINITI QX56 engine

EC-308
< COMPONENT DIAGNOSIS >[VK56DE]
P1217 ENGINE OVER TEMPERATURE
4. Make sure that cooling fan operates.
OK or NG
OK >> GO TO 4.
NG >> Check cooling fan control circuit. (Go to "PROCEDURE
A".)
4.CHECK COOLING SYSTEM FOR LEAK
Refer to CO-10, "
Inspection".
OK or NG
OK >> GO TO 5.
NG >> Check the following for leak. •Hose
• Radiator
• Radiator cap
• Water pump
• Reservoir tank
5.CHECK COMPONENT PARTS
Check the following.
• RESERVOIR TANK CAP (Refer to CO-10, "
Inspection".)
• Thermostat. (Refer to CO-22, "
Removal and Installation".)
• Engine coolant temperature sensor. (Refer to EC-126, "
Component Inspection".)
OK or NG
OK >> GO TO 6.
NG >> Replace malfunctioning component.
6.CHECK MAIN 13 CAUSES
If the cause cannot be isolated, go to EC-308, "
Main 13 Causes of Overheating".
>> INSPECTION END
Main 13 Causes of OverheatingINFOID:0000000001351718
SEF882V
Engine Step Inspection item EquipmentStandardReference page
OFF 1 • Blocked radiator • Blocked condenser
• Blocked radiator grille
• Blocked bumper • Visual
No blocking —
2 • Coolant mixture • Coolant tester 50 - 50% coolant mixtureCO-10
3 • Coolant level • VisualCoolant up to MAX level in
reservoir tank and radiator
filler neck CO-11, "Changing Engine
Coolant"
4 • Reservoir tank cap • Pre
ssure tester 95 - 125 kPa
(0.97 - 1.28 kg/cm2, 14 -
18 psi) (Limit) CO-10, "
Inspection"
ON*25 • Coolant leaks
• VisualNo leaks CO-10, "Inspection"
ON*26 • Thermostat • Touch the upper and
lower radiator hoses Both hoses should be hot
CO-22, "Removal and In-
stallation"
ON*17 • Cooling fan • CONSULT-IIIOperating See trouble diagnosis for
DTC P1217 ( EC-36
).
Revision: March 2010 2008 QX56

P1217 ENGINE OVER TEMPERATUREEC-309
< COMPONENT DIAGNOSIS > [VK56DE]
C
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G H
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EC
NP
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*1: Turn the ignition switch ON.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
For more information, refer to
CO-8, "
Troubleshooting Chart".
OFF 8 • Combustion gas leak • Color checker chemical
tester 4 Gas analyzerNegative
—
ON*
39 • Coolant temperature gauge • Visual Gauge less than 3/4 when
driving —
• Coolant overflow to res- ervoir tank • Visual
No overflow during driving
and idling CO-11, "
Changing Engine
Coolant"
OFF*410 • Coolant return from res-
ervoir tank to radiator • Visual Should be initial level in
reservoir tank CO-11, "Changing Engine
Coolant"
OFF 12 • Cylinder head
• Straight gauge feeler
gauge 0.1 mm (0.004 in) Maxi-
mum distortion (warping) EM-72, "Inspection After
Disassembly"
13 • Cylinder block and pis-
tons • Visual No scuffing on cylinder
walls or piston EM-90, "Inspection After
Disassembly"
Engine Step Inspection item
EquipmentStandardReference page
Revision: March 2010 2008 QX56

EC-314
< COMPONENT DIAGNOSIS >[VK56DE]
P1421 COLD START CONTROL
P1421 COLD START CONTROL
DescriptionINFOID:0000000001351886
ECM controls ignition timing and engine idle speed when engine is started with prewarming up condition.
This control promotes the activation of three way catalyst by heating the catalyst and reduces emissions.
On Board Diagn
osis LogicINFOID:0000000001351887
DTC Confirmation ProcedureINFOID:0000000001351888
NOTE:
• If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
• If DTC P1421 is displayed with other DTC, firs t perform the trouble diagnosis for other DTC.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
WITH CONSULT-IIl
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Select “DATA MONITOR” mode with CONSULT-IIl.
4. Check that the “COOLAN TEMP/S” indication is between 4 °C (39° F) and 36 °C (97° F).
If “COOLAN TEMP/S” indication is within the specified value, go to the following step.
If “COOLANT TEMP/S” indication is out of the s pecified value, cool engine down or warm engine up and
go to step 1.
5. Start engine and let it idle for 5 minutes.
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to EC-314, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-lII” above.
Diagnosis ProcedureINFOID:0000000001351889
1.PERFORM IDLE AIR VOLUME LEARNING
Perform EC-18, "
Idle Air Volume Learning".
Is Idle Air Volume Lear ning carried out successfully?
Ye s o r N o
Ye s > > G O T O 2 .
No >> Follow the instruction of Idle Air Volume Learning.
2.CHECK INTAKE SYSTEM
Check for the cause of intake air volume lacking. Refer to the following.
• Crushed intake air passage
• Intake air passage clogging
OK or NG
OK >> GO TO 3.
NG >> Repair or replace malfunctioning part
3.CHECK FUEL INJECTION SYSTEM FUNCTION
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P1421
1421 Cold start emission reduction
strategy monitoring ECM does not control ignition timing and engine
idle speed properly when engine is started with
prewarming up condition. • Lack of intake air volume
• Fuel injection system
•ECM
Revision: March 2010
2008 QX56

EC-316
< COMPONENT DIAGNOSIS >[VK56DE]
P1550 BATTERY CURRENT SENSOR
P1550 BATTERY CURRENT SENSOR
Component DescriptionINFOID:0000000001351890
The power generation voltage variable control enables fuel con-
sumption to be decreased by reducing the engine load which is
caused by the power generation of the generator. The battery cur-
rent sensor (1) is installed to the battery cable at the negative termi-
nal. The sensor measures the charging/discharging current of the
battery. Based on the sensor signal, ECM judges whether or not the
power generation voltage variable control is performed. When per-
forming the power generation voltage variable control, ECM calcu-
lates the target power generation voltage based on the sensor
signal. And ECM sends the calculated value as the power genera-
tion command value to IPDM E/R. For the details of the power gen-
eration voltage variable control, refer to
CHG-9, "
System
Description".
: Vehicle front
CAUTION:
Do not connect the electrical compon ent or the ground wire directly to the battery terminal. The con-
nection causes the malfunction of th e power generation voltage variable control, and then the battery
discharge may occur.
On Board Diagn osis LogicINFOID:0000000001351892
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P1550 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-293
.
DTC Confirmation ProcedureINFOID:0000000001351893
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 8V at idle.
WITH CONSULT-IIl
1. Start engine and wait at least 10 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-316, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-IlI” above.
Diagnosis ProcedureINFOID:0000000001351895
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body.
BBIA0744E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P1550
1550 Battery current sensor circuit
range/performance The output voltage of the battery current
sensor remains within the specified
range while engine is running. • Harness or connectors
(The sensor circuit is open or shorted.)
• Battery current sensor
Revision: March 2010 2008 QX56

EC-320
< COMPONENT DIAGNOSIS >[VK56DE]
P1551, P1552 BATTERY CURRENT SENSOR
P1551, P1552 BATTERY CURRENT SENSOR
Component DescriptionINFOID:0000000001528770
The power generation voltage variable control enables fuel con-
sumption to be decreased by reducing the engine load which is
caused by the power generation of the generator. The battery cur-
rent sensor (1) is installed to the battery cable at the negative termi-
nal. The sensor measures the charging/discharging current of the
battery. Based on the sensor signal, ECM judges whether or not the
power generation voltage variable control is performed. When per-
forming the power generation voltage variable control, ECM calcu-
lates the target power generation voltage based on the sensor
signal. And ECM sends the calculated value as the power genera-
tion command value to IPDM E/R. For the details of the power gen-
eration voltage variable control, refer to
CHG-9, "
System
Description".
: Vehicle front
CAUTION:
Do not connect the electrical compon ent or the ground wire directly to the battery terminal. The con-
nection causes the malfunction of th e power generation voltage variable control, and then the battery
discharge may occur.
On Board Diagn osis LogicINFOID:0000000001528772
The MIL will not light up for these self-diagnoses.
NOTE:
If DTC P1551 or P1552 is displayed with DTC P0643, first perform the tro\
ubl e diagnosis for DTC P0643.
Refer to EC-293, "
On Board Diagnosis Logic".
DTC Confirmation ProcedureINFOID:0000000001528773
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm th at battery voltage is more than 8V with ignition
switch ON
WITH CONSULT-III
1. Turn ignition switch ON.
2. Wait at least 10 seconds.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-320, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001528775
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body.
BBIA0744E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P1551
1551 Battery current sensor circuit
low input An excessively low voltage from the sensor
is sent to ECM.
• Harness or connectors
(The sensor circuit is open or shorted.)
• Battery current sensor
P1552
1552 Battery current sensor circuit
high input An excessively high voltage from the sensor
is sent to ECM.
Revision: March 2010
2008 QX56

EC-324
< COMPONENT DIAGNOSIS >[VK56DE]
P1553 BATTERY CURRENT SENSOR
P1553 BATTERY CURRENT SENSOR
Component DescriptionINFOID:0000000001351904
The power generation voltage variable control enables fuel con-
sumption to be decreased by reducing the engine load which is
caused by the power generation of the generator. The battery cur-
rent sensor (1) is installed to the battery cable at the negative termi-
nal. The sensor measures the charging/discharging current of the
battery. Based on the sensor signal, ECM judges whether or not the
power generation voltage variable control is performed. When per-
forming the power generation voltage variable control, ECM calcu-
lates the target power generation voltage based on the sensor
signal. And ECM sends the calculated value as the power genera-
tion command value to IPDM E/R. For the details of the power gen-
eration voltage variable control, refer to
CHG-9, "
System
Description".
: Vehicle front
CAUTION:
Do not connect the electrical compon ent or the ground wire directly to the battery terminal. The con-
nection causes the malfunction of th e power generation voltage variable control, and then the battery
discharge may occur.
On Board Diagn osis LogicINFOID:0000000001351906
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P1553 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-293
.
DTC Confirmation ProcedureINFOID:0000000001351907
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 8V at idle.
WITH CONSULT-IIl
1. Start engine and wait at least 10 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-324, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-IIl” above.
Diagnosis ProcedureINFOID:0000000001351909
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body.
BBIA0744E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P1553
1553 Battery current sensor performance The signal voltage transmitted from the
sensor to ECM is higher than the amount
of the maximum power generation. • Harness or connectors
(The sensor circuit is open or shorted.)
• Battery current sensor
Revision: March 2010 2008 QX56

EC-328
< COMPONENT DIAGNOSIS >[VK56DE]
P1554 BATTERY CURRENT SENSOR
P1554 BATTERY CURRENT SENSOR
Component DescriptionINFOID:0000000001528777
The power generation voltage variable control enables fuel con-
sumption to be decreased by reducing the engine load which is
caused by the power generation of the generator. The battery cur-
rent sensor (1) is installed to the battery cable at the negative termi-
nal. The sensor measures the charging/discharging current of the
battery. Based on the sensor signal, ECM judges whether or not the
power generation voltage variable control is performed. When per-
forming the power generation voltage variable control, ECM calcu-
lates the target power generation voltage based on the sensor
signal. And ECM sends the calculated value as the power genera-
tion command value to IPDM E/R. For the details of the power gen-
eration voltage variable control, refer to
CHG-9, "
System
Description".
: Vehicle front
CAUTION:
Do not connect the electrical compon ent or the ground wire directly to the battery terminal. The con-
nection causes the malfunction of th e power generation voltage variable control, and then the battery
discharge may occur.
On Board Diagn osis LogicINFOID:0000000001528779
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P1554 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-293, "
On Board Diagnosis Logic".
Overall Function CheckINFOID:0000000001528780
Use this procedure to check the overall function of the battery current sensor circuit. During this check, a 1st
trip DTC might not be confirmed.
TESTING CONDITION:
• Before performing the following procedure, confirm th at battery voltage is more than 12.8V at idle.
• Before performing the following procedure, confi rm that all load switches and A/C switch are turned
OFF.
WITH CONSULT-III
1. Start engine and let it idle.
2. Select “BAT CUR SEN” in “DATA MONITOR” mode with CONSULT-III.
3. Check “BAT CUR SEN” indication for 10 seconds.
“BAT CUR SEN” should be above 2,300mV at least once.
4. If NG, go to EC-329, "
Diagnosis Procedure".
WITH GST
1. Start engine and let it idle.
BBIA0744E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P1554
1554 Battery current sensor performance The output voltage of the battery current
sensor is lower than the specified value
while the battery voltage is high enough. • Harness or connectors
(The sensor circuit is open or shorted.)
• Battery current sensor
Revision: March 2010 2008 QX56

P1572 ICC BRAKE SWITCHEC-341
< COMPONENT DIAGNOSIS > [VK56DE]
C
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EC
NP
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P1572 ICC BRAKE SWITCH
Component DescriptionINFOID:0000000001365766
When the brake pedal is depressed, ICC brake switch is turned OFF
and stop lamp switch is turned ON. ECM detects the state of the
brake pedal by this input of two kinds (ON/OFF signal).
Refer to
CCS-13
for the ICC function.
On Board Diagnosis LogicINFOID:0000000001365768
•This diagnosis has the on e trip detection logic.
• The MIL will not light up for this self-diagnosis.
NOTE:
• If DTC P1572 is displayed with DT C P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-291, "
On Board Diagnosis Logic".
• This self-diagnosis has the one trip detection logic. When malfunction A is detected, DTC is not
stored in ECM memory. And in that case, 1st trip DTC and 1st trip freeze frame data are displayed.
1st trip DTC is erased when ignition switch OFF. And even when ma lfunction A is detected in two
consecutive trips, DTC is not stored in ECM memory.
DTC Confirmation ProcedureINFOID:0000000001365769
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
• If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
• Procedure for malfunction B is not described here. It takes extremely long time to complete procedure for malfunction B. By performing procedure for malfunction A, the incident that causes malfunction B can be
detected.
TESTING CONDITION:
Steps 4 and 5 may be conducted with the drive wheels li fted in the shop or by driving the vehicle. If a
road test is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-IIl
1. Start engine (VDC switch OFF).
2. Select “DATA MONITOR” mode with CONSULT-IIl.
3. Press MAIN switch and make sure that CRUISE lamp lights up.
4. Drive the vehicle for at least 5 consecutive seconds under the following conditions.
BBIA0470E
DTC No.Trouble diagnosis
name DTC detecting condition
Possible cause
P1572
1572 ICC brake switch A)
When vehicle speed is above 30 km/h (19
MPH), ON signals from the stop lamp
switch and the ICC brake switch are sent to
ECM at the same time. • Harness or connectors
(The stop lamp switch circuit is shorted.)
• Harness or connectors
(The ICC brake switch circuit is shorted.)
•Stop lamp switch
• ICC brake switch
• ICC brake hold relay
• Incorrect stop lamp switch installation
• Incorrect ICC brake switch installation
•ECM
B)
ICC brake switch signal is not sent to ECM
for extremely long time while the vehicle is
driving
Revision: March 2010
2008 QX56