check engine INFINITI QX56 2008 Factory Service Manual

IGNITION SIGNALEC-411
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IGNITION SIGNAL
Component DescriptionINFOID:0000000001365892
IGNITION COIL & POWER TRANSISTOR
The ignition signal from the ECM is sent to and amplifi
ed by the power transistor. The power transistor turns
ON and OFF the ignition coil primary circuit. This ON/OFF operation induces the proper high voltage in the coil
secondary circuit.
Diagnosis ProcedureINFOID:0000000001365894
1.CHECK ENGINE START
Turn ignition switch OFF, and restart engine.
Is engine running?
Ye s o r N o
Yes (With CONSULT-IIl)>>GO TO 2.
Yes (Without CONSULT-lII)>>GO TO 3.
No >> GO TO 4.
2.CHECK OVERALL FUNCTION
With CONSULT-IIl
1. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-lII.
2. Make sure that each circuit produces a momentary engine speed drop.
OK or NG
OK >> INSPECTION END
NG >> GO TO 10.
3.CHECK OVERALL FUNCTION
Without CONSULT-IIl
1. Let engine idle.
2. Read the voltage signal between ECM terminals 46, 60, 61, 62, 65, 79, 80, 81 and ground with an oscilloscope.
3. Verify that the oscilloscope screen shows the signal wave as shown below.
NOTE:
The pulse cycle changes depending on rpm at idle.
OK or NG
1. Ignition coils (with power transistor) (bank 2) 2. Ignition coils (with power transistor)
(bank 1)
BBIA0777E
PBIB2094E
PBIB0044E
Revision: March 2010 2008 QX56

IGNITION SIGNALEC-415
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7. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
Do not use CONSULT-IIl to release fuel pressure, or fuel pres-
sure applies again during the following procedure.
8. Start engine.
9. After engine stalls, crank it two or three times to release all fuel pressure.
10. Turn ignition switch OFF.
11. Remove all ignition coil harness connectors to avoid the electri- cal discharge from the ignition coils.
12. Remove ignition coil and spark plug of the cylinder to be checked.
13. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
14. Connect spark plug and harness connector to ignition coil.
15. Fix ignition coil using a rope etc. with gap of 13 - 17 mm between the edge of the spark plug and grounded metal portion
as shown in the figure.
16. Crank engine for about 3 seconds, and check whether spark is generated between the spark plug and the grounded metal por-
tion.
CAUTION:
• Do not approach to the spark plug and the ignition coil
within 50cm. Be careful not to get an electrical shock
while checking, because the el ectrical discharge voltage
becomes 20kV or more.
• It might cause to damage the ignition coil if the gap of more than 17 mm is taken.
NOTE:
When the gap is less than 13 mm, the spark might be generated even if the coil is malfunctioning.
17. If NG, replace ignition coil with power transistor.
CONDENSER-1
1. Turn ignition switch OFF.
2. Disconnect condenser-1 harness connector.
3. Check resistance between condenser-1 terminals 1 and 2. Spark should be generated.
BBIA0380E
PBIB2325E
Resistance
Above 1 MΩ at 25 °C (77 °F)
PBIB0794E
Revision: March 2010 2008 QX56

EC-416
< COMPONENT DIAGNOSIS >[VK56DE]
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
System DescriptionINFOID:0000000001351317
From the beginning of refueling, the air and vapor insi
de the fuel tank go through refueling EVAP vapor cut
valve and EVAP/ORVR line to the EVAP canister. The vapor is absorbed by the EVAP canister and the air is
released to the atmosphere.
When the refueling has reached the full level of the fuel tank, the refueling EVAP vapor cut valve is closed and
refueling is stopped because of auto shut-off. The vapor which was absorbed by the EVAP canister is purged
during driving.
WARNING:
When conducting inspections below, be sure to observe the following:
• Put a “CAUTION: FLAMMABLE” sign in workshop.
• Do not smoke while servicing fuel system. Keep open flames and sparks away from work area.
• Be sure to furnish the workshop with a CO
2 fire extinguisher.
CAUTION:
• Before removing fuel line parts, carry out the following procedures:
- Put drained fuel in an explosion-pr oof container and put lid on securely.
- Release fuel pressure from fuel line. Refer to EC-494, "
Fuel Pressure Check" .
- Disconnect battery ground cable.
• Always replace O-ring when the fu el gauge retainer is removed.
• Do not kink or twist hose and tube when they are installed.
• Do not tighten hose and clamps excessively to avoid damaging hoses.
• After installation, run engine and check for fuel leaks at connection.
• Do not attempt to top off the fuel tank afte r the fuel pump nozzle shuts off automatically.
Continued refueling may cause fuel overflow, r esulting in fuel spray and possibly a fire.
Diagnosis ProcedureINFOID:0000000001351318
SYMPTOM: FUEL ODOR FROM EVAP CANISTER IS STRONG.
1.CHECK EVAP CANISTER
1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor attached.
2. Weigh the EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor
attached.
The weight should be l ess than 2.5 kg (5.5 lb).
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2.CHECK IF EVAP CANISTER SATURATED WITH WATER
PBIB1068E
Revision: March 2010 2008 QX56

REFRIGERANT PRESSURE SENSOREC-423
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REFRIGERANT PRESSURE SENSOR
Component DescriptionINFOID:0000000001365897
The refrigerant pressure sensor is installed at the condenser 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.
Diagnosis ProcedureINFOID:0000000001365899
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 fan switch ON.
3. Check voltage between ECM terminal 70 and ground with CON- SULT-IIl or tester.
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
2.CHECK GROUND CONNECTIONS
1. Turn A/C switch and blower fan switch OFF.
2. Turn ignition switch OFF.
3. Loosen and retighten three ground screws on the body.
BBIA0445E
PBIB2657E
Voltage: 1.0 - 4.0V
PBIB1188E
Revision: March 2010 2008 QX56

ECM
EC-467
< ECU DIAGNOSIS > [VK56DE]
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Procedures for clearing the DTC and the 1st trip DT
C from the ECM memory are described in "HOW TO
ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION".
For malfunctions in which 1st trip DTCs are displa yed, refer to "EMISSION-RELATED DIAGNOSTIC INFOR-
MATION ITEMS". These items are required by legal r egulations to continuously monitor the system/compo-
nent. In addition, the items monitored non-cont inuously are also displayed on CONSULT-III.
1st trip DTC is specified in Service $07 of SAE J1979. 1st trip DTC detection occurs without lighting up the MIL
and therefore does not warn the driver of a malfunction. However, 1st trip DTC detection will not prevent the
vehicle from being tested, for example during Inspection/Maintenance (I/M) tests.
When a 1st trip DTC is detected, check, print out or write down and erase (1st trip) DTC and Freeze Frame
data as specified in Work Flow procedure Step 2, refer to EC-8, "
Trouble Diagnosis Introduction". Then per-
form DTC Confirmation Procedure or Overall Function Che ck to try to duplicate the malfunction. If the mal-
function is duplicated, the item requires repair.
How to Read DTC and 1st Trip DTC
DTC and 1st trip DTC can be read by the following methods.
With CONSULT-III
With GST
CONSULT-III or GST (Generic Scan Tool ) Examples: P0340, P0850, P1148, etc.
These DTCs are prescribed by SAE J2012.
(CONSULT-III also displays the malfunctioning component or system.)
No Tools
The number of blinks of the MIL in the Diagnostic Test Mode II (Self-Diagnostic Results) indicates the DTC.
Example: 0340, 0850, 1148, etc.
These DTCs are controlled by NISSAN.
• 1st trip DTC No. is the same as DTC No.
• Output of a DTC indicates a malfunc tion. However, GST or the Diagnostic Test Mode II do not indi-
cate whether the malfunction is stil l occurring or has occurred in the past and has returned to nor-
mal. CONSULT-III can identify malfunction status as shown below. Therefore, using CONSULT-III (if
available) is recommended.
DTC or 1st trip DTC of a malfunction is display ed in SELF-DIAGNOSTIC RESULTS mode of CONSULT-III.
Time data indicates how many times the vehicle was driven after the last detection of a DTC.
If the DTC is being detected currently, the time data will be [0].
If a 1st trip DTC is stored in the ECM, the time data will be [1t].
FREEZE FRAME DATA AND 1ST TRIP FREEZE FRAME DATA
The ECM records the driving conditions such as fuel system status, calculated load value, engine coolant tem-
perature, short term fuel trim, long term fuel trim, engi ne speed, vehicle speed, absolute throttle position, base
fuel schedule and intake air temperature at the moment a malfunction is detected.
Data which are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data.
The data, stored together with the DTC data, are ca lled freeze frame data and displayed on CONSULT-III or
GST. The 1st trip freeze frame dat a can only be displayed on the CONSULT-III screen, not on the GST. For
details, see EC-63, "
CONSULT-III Function (ENGINE)".
Only one set of freeze frame data (either 1st trip freez e frame data or freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM me mory along with the 1st trip DTC. There is no priority
for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once
freeze frame data (2nd trip detection/MIL on) is stored in the ECM memory, 1st trip freeze frame data is no
longer stored. Remember, only one set of freeze frame data can be stored in the ECM. The ECM has the fol-
lowing priorities to update the data.
For example, the EGR malfunction (Priority: 2) was detected and the fr eeze frame data was stored in the 2nd
trip. After that when the misfire (Priority: 1) is detected in another trip, the freeze frame data will be updated
from the EGR malfunction to the misfire. The 1st trip freeze frame data is updated each time a different mal-
function is detected. There is no priority for 1st tr ip freeze frame data. However, once freeze frame data is
stored in the ECM memory, 1st trip freeze data is no longer stored (because only one freeze frame data or 1st
trip freeze frame data can be stored in the ECM). If freeze frame data is stored in the ECM memory and freeze
Priority Items
1 Freeze frame data Misfire — DTC: P0300 - P0308
Fuel Injection System Function — DTC: P0171, P0172, P0174, P0175
2 Except the above items (Includes A/T related items)
3 1st trip freeze frame data
Revision: March 2010 2008 QX56

ECM
EC-473
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• Sea level
• Flat road
• Ambient air temperature: 20 - 30
°C (68 - 86 °F)
• Diagnosis is performed as quickly as possible under normal conditions. Under different conditions [For example: ambient air temperature other than 20 - 30 °C (68 - 86° F)], diagno-
sis may also be performed.
Pattern 1:
• The engine is started at the engine coolant temperature of −10 to 35 °C (14 to 95 °F)
(where the voltage between the ECM terminal 73 and ground is 3.0 - 4.3V).
• The engine must be operated at idle speed until the engine coolant temperature is greater than 70 °C
(158° F) (where the voltage between the ECM te rminal 73 and ground is lower than 1.4V).
• The engine is started at the fuel tank temperature of warmer than 0 °C (32° F) (where the voltage
between the ECM terminal 107 and ground is less than 4.1V).
Pattern 2:
• When steady-state driving is performed again even afte r it is interrupted, each diagnosis can be conducted.
In this case, the time required for diagnosis may be extended.
Pattern 3:
• Operate vehicle following the driving pattern shown in the figure.
• Release the accelerator pedal during decelerating vehicle speed from 90 km/h (56 MPH) to 0 km/h (0 MPH).
Pattern 4:
• The accelerator pedal must be held very steady during steady- state driving.
• If the accelerator pedal is moved, the test must be conducted all over again.
*1: Depress the accelerator pedal until vehicle speed is 90 km/h (56
MPH), then release the accelerator pedal and keep it released for
more than 10 seconds. Depress the accelerator pedal until vehicle
speed is 90 km/h (56 MPH) again.
*2: Checking the vehicle speed with GST is advised.
Suggested Transmi ssion Gear Position
Set the selector lever in the D position with the overdrive switch turned ON.
TEST VALUE AND TEST LIMIT
The following is the information specified in Service $06 of SAE J1979.
The test value is a parameter used to determine whether a system/circuit diagnostic test is OK or NG while
being monitored by the ECM during self-diagnosis. The test limit is a reference value which is specified as the
maximum or minimum value and is compared with the test value being monitored.
These data (test value and test limit) are specified by On Boad Monitor ID(OBDMID), Test ID (TID), Unit and
Scaling ID and can be displayed on the GST screen.
The items of the test value and test limit will be disp layed with GST screen which items are provided by the
ECM. (eg., if the bank 2 is not applied on this v ehicle, only the items of the bank 1 is displayed)
PBIB2244E
Revision: March 2010 2008 QX56

ECM
EC-479
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HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION
How to Erase DTC
WITH CONSULT-III
The emission related diagnostic information in the ECM can be erased by selecting “All Erase” in the “Descrip-
tion” of “FINAL CHECK” mode with CONSULT-III.
WITH GST
The emission related diagnostic information in the ECM can be erased by selecting Service $04 with GST.
NOTE:
If the DTC is not for A/T related items (see EC-462, "
DTC Index"), skip step 2.
1. If the ignition switch stays ON after repair work, be su re to turn ignition switch OFF once. Wait at least 10
seconds and then turn it ON (engine stopped) again.
2. Perform TM-30, "
OBD-II Diagnostic Trouble Code (DTC)". (The DTC in TCM will be erased)
3. Select Service $04 with GST (Generic Scan Tool).
No Tools
NOTE:
MISFIRE A3H No.2 Cylinder Misfire
P0302 0BH 24H
EWMA (Exponential Weighted
Moving Average) misfire counts
for last 10 driving cycles
P0302 0CH 24H Misfire counts for last/current driv-
ing cycles
A4H No.3 Cylinder Misfire P0303 0BH 24H
EWMA (Exponential Weighted
Moving Average) misfire counts
for last 10 driving cycles
P0303 0CH 24H Misfire counts for last/current driv-
ing cycles
A5H No.4 Cylinder Misfire P0304 0BH 24H
EWMA (Exponential Weighted
Moving Average) misfire counts
for last 10 driving cycles
P0304 0CH 24H Misfire counts for last/current driv-
ing cycles
A6H No.5 Cylinder Misfire P0305 0BH 24H
EWMA (Exponential Weighted
Moving Average) misfire counts
for last 10 driving cycles
P0305 0CH 24H Misfire counts for last/current driv-
ing cycles
A7H No.6 Cylinder Misfire P0306 0BH 24H
EWMA (Exponential Weighted
Moving Average) misfire counts
for last 10 driving cycles
P0306 0CH 24H Misfire counts for last/current driv-
ing cycles
A8H No.7 Cylinder Misfire P0307 0BH 24H
EWMA (Exponential Weighted
Moving Average) misfire counts
for last 10 driving cycles
P0307 0CH 24H Misfire counts for last/current driv-
ing cycles
A9H No.8 Cylinder Misfire P0308 0BH 24H
EWMA (Exponential Weighted
Moving Average) misfire counts
for last 10 driving cycles
P0308 0CH 24H Misfire counts for last/current driv-
ing cycles
Item
OBD-
MID Self-diagnostic test item
DTCTest value and Test
limit
(GST display) Description
TID Unit and
Scaling ID
Revision: March 2010 2008 QX56

PRECAUTIONSEC-487
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5. When the repair work is completed, return the ignition switch to the
″LOCK ″ position before connecting
the battery cables. (At this time, the steering lock mechanism will engage.)
6. Perform a self-diagnosis check of al l control units using CONSULT-III.
On Board Diagnosis (OBD) System of Engine and A/TINFOID:0000000001351222
The ECM has an on board diagnostic system . It will light up the malfunction indicator lamp (MIL) to warn the
driver of a malfunction causing emission deterioration.
CAUTION:
• Be sure to turn the ignition switch OFF and di sconnect the negative battery cable before any repair
or inspection work. The open/short circuit of re lated switches, sensors, solenoid valves, etc. will
cause the MIL to light up.
• Be sure to connect and lock the connectors secure ly after work. A loose (unlocked) connector will
cause the MIL to light up due to the open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)
• Certain systems and components, especially those related to OBD, may use a new style slide-lock-
ing type harness connector. For description and how to disconnect, refer to PG-65
.
• Be sure to route and secure the harnesses properly after work. The interference of the harness with
a bracket, etc. may cause the MIL to li ght up due to the short circuit.
• Be sure to connect rubber tubes properly afte r work. A misconnected or disconnected rubber tube
may cause the MIL to light up due to the malfuncti on of the EVAP system or fuel injection system,
etc.
• Be sure to erase the unnecessary malfunction information (repairs completed) from the ECM and TCM (Transmission control module) before returning the vehicle to the customer.
PrecautionINFOID:0000000006211821
•Always use a 12 volt battery as power source.
• Do not attempt to disconnect battery cables while engine is
running.
• Before connecting or disc onnecting the ECM harness con-
nector, turn ignition switch OFF and disconnect negative bat-
tery cable. Failure to do so may damage the ECM because
battery voltage is applied to ECM even if ignition switch is
turned OFF.
• Before removing parts, turn ig nition switch OFF and then dis-
connect negative battery cable.
• Do not disassemble ECM.
• If a battery cable is disconnected, the memory will return to
the ECM value.
The ECM will now start to sel f-control at its initial value.
Engine operation can vary slight ly when the terminal is dis-
connected. However, this is not an indication of a malfunc-
tion. Do not replace parts because of a slight variation.
• If the battery is disconnected, the following emission-related
diagnostic information will be lost within 24 hours.
- Diagnostic trouble codes
- 1st trip diagnostic trouble codes
- Freeze frame data
- 1st trip freeze frame data
- System readiness test (SRT) codes
- Test values
- <Flexible Fuel Vehicle>
Presumed ethanol mixture ratio
SEF289H
PBIB1164E
Revision: March 2010 2008 QX56

EC-488
< PRECAUTION >[VK56DE]
PRECAUTIONS
•
When connecting ECM harness co nnector, fasten it securely
with a lever as far as it will go as shown in the figure.
• When connecting or disconnect ing pin connectors into or
from ECM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on ECM pin
terminal, when connecting pin connectors.
• Securely connect ECM harness connectors.
A poor connection can cause an extremely high (surge) volt-
age to develop in coil and co ndenser, thus resulting in dam-
age to ICs.
• Keep engine control system harness at least 10 cm (4 in) away
from adjacent harness, to preven t engine control system mal-
functions due to receiving external noise, degraded operation
of ICs, etc.
• Keep engine control system parts and harness dry.
• Before replacing ECM, perform ECM Terminals and Reference
Value inspection and make sure ECM functions properly.
Refer to EC-429, "
ECM Terminal and Reference Value".
• Handle mass air flow sensor carefully to avoid damage.
• Do not disassemble m ass air flow sensor.
• Do not clean mass air flow sensor with any type of detergent.
• Do not disassemble electric throttle control actuator.
• Even a slight leak in the ai r intake system can cause serious
incidents.
• Do not shock or jar the camshaft position sensor (PHASE),
crankshaft position sensor (POS).
• After performing each TROUBLE DIAGNOSIS, perform DTC
Confirmation Procedure or Overall Function Check.
The DTC should not be displ ayed in the DTC Confirmation
Procedure if the repair is co mpleted. The Overall Function
Check should be a good result if the repair is completed.
BBIA0387E
PBIB0090E
MEF040D
SEF217U
Revision: March 2010 2008 QX56

EC-492
< PREPARATION >[VK56DE]
PREPARATION
Commercial Service Tool
INFOID:0000000001351225
(J-45488)
Quick connector re-
lease Remove fuel tube quick connectors in engine
room.
(J-23688)
Engine coolant refrac-
tometer Checking concentration of ethylene glycol in en-
gine coolant
Tool number
(Kent-Moore No.)
Tool name
Description
PBIC0198E
WBIA0539E
Tool name
(Kent-Moore No.)
Description
Leak detector
i.e.: (J-41416) Locating the EVAP leak
EVAP service port
adapter
i.e.: (J-41413-OBD) Applying positive pressure through EVAP service
port
Fuel filler cap adapter
i.e.: (MLR-8382) Checking fuel tank vacuum relief valve opening
pressure
Socket wrench Removing and installing engine coolant tempera-
ture sensor
S-NT703
S-NT704
S-NT815
S-NT705
Revision: March 2010 2008 QX56