EC-68
[VQ35DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Revision: 2004 November 2004 FX35/FX45
2. Perform AT- 4 0 . (The DTC in TCM will be erased.)
3. Select MODE 4 with GST (Generic Scan Tool).
No Tools
NOTE:
If the DTC is not for A/T related items (see EC-15
), skip step 2.
1. If the ignition switch stays ON after repair work, be sure to turn ignition switch OFF once.
Wait at least 10 seconds and then turn it ON (engine stopped) again.
2. Perform AT- 4 1
. (The DTC in TCM will be erased.)
3. Change the diagnostic test mode from Mode II to Mode I by depressing the accelerator pedal. Refer to
EC-70, "
HOW TO SWITCH DIAGNOSTIC TEST MODE" .
If the battery is disconnected, the emission-related diagnostic information will be lost within 24
hours.
The following data are cleared when the ECM memory is erased.
–Diagnostic trouble codes
–1st trip diagnostic trouble codes
–Freeze frame data
–1st trip freeze frame data
–System readiness test (SRT) codes
–Test values
–Others
Actual work procedures are explained using a DTC as an example. Be careful so that not only the DTC, but all
of the data listed above, are cleared from the ECM memory during work procedures.
IVIS (Infiniti Vehicle Immobilizer System — NATS)ABS008GC
If the security indicator lights up with the ignition switch in
the ON position or “NATS MALFUNCTION” is displayed on
“SELF-DIAG RESULTS” screen, perform self-diagnostic
results mode with CONSULT-II using NATS program card.
Refer to BL-206, "
IVIS (INFINITI VEHICLE IMMOBILIZER
SYSTEM-NATS)" .
Confirm no self-diagnostic results of IVIS (NATS) is dis-
played before touching “ERASE” in “SELF-DIAG RESULTS”
mode with CONSULT-II.
When replacing ECM, initialization of IVIS (NATS) system
and registration of all IVIS (NATS) ignition key IDs must be
carried out with CONSULT-II using NATS program card.
Therefore, be sure to receive all keys from vehicle owner. Regarding the procedures of IVIS (NATS)
initialization and IVIS (NATS) ignition key ID registration, refer to CONSULT-II operation manual,
IVIS/NVIS.
Malfunction Indicator Lamp (MIL)ABS006KM
DESCRIPTION
The MIL is located on the instrument panel.
1. The MIL will light up when the ignition switch is turned ON with-
out the engine running. This is a bulb check.
If the MIL does not light up, refer to DI-39, "
WARNING LAMPS" ,
or see EC-641
.
2. When the engine is started, the MIL should go off.
If the MIL remains on, the on board diagnostic system has
detected an engine system malfunction.
SEF543X
SEF217U
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-69
[VQ35DE]
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2004 November 2004 FX35/FX45
ON BOARD DIAGNOSTIC SYSTEM FUNCTION
The on board diagnostic system has the following four functions.
When there is an open circuit on MIL circuit, the ECM cannot warn the driver by lighting MIL up when there is
malfunction on engine control system.
Therefore, when electrical controlled throttle and part of ECM related diagnoses are continuously detected as
NG for 5 trips, ECM warns the driver that engine control system malfunctions and MIL circuit is open by means
of operating fail-safe function.
The fail-safe function also operates when above diagnoses except MIL circuit are detected and demands the
driver to repair the malfunction.
MIL Flashing Without DTC
If the ECM is in Diagnostic Test Mode II, MIL may flash when engine is running. In this case, check ECM diag-
nostic test mode. EC-70, "
HOW TO SWITCH DIAGNOSTIC TEST MODE" .
How to switch the diagnostic test (function) modes, and details of the above functions are described later. EC-
70, "HOW TO SWITCH DIAGNOSTIC TEST MODE" .
The following emission-related diagnostic information is cleared when the ECM memory is erased.
Diagnostic trouble codes
1st trip diagnostic trouble codes
Freeze frame data
1st trip freeze frame data
System readiness test (SRT) codes
Test values
Others
Diagnostic Test
ModeKEY and ENG.
StatusFunction Explanation of Function
Mode I Ignition switch in
ON position
Engine stoppedBULB CHECK This function checks the MIL bulb for damage (blown,
open circuit, etc.).
If the MIL does not come on, check MIL circuit.
Engine running MALFUNCTION
WARNINGThis is a usual driving condition. When a malfunction is
detected twice in two consecutive driving cycles (two trip
detection logic), the MIL will light up to inform the driver
that a malfunction has been detected.
The following malfunctions will light up or blink the MIL in
the 1st trip.
Misfire (Possible three way catalyst damage)
One trip detection diagnoses
Mode II Ignition switch in
ON position
Engine stoppedSELF-DIAGNOSTIC
RESULTSThis function allows DTCs and 1st trip DTCs to be read.
Engine running HEATED OXYGEN SENSOR 1
MONITORThis function allows the fuel mixture condition (lean or
rich), monitored by heated oxygen sensor 1, to be read.
Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut
EC-86
[VQ35DE]
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
10. CHECK IGNITION TIMING
1. Run engine at idle.
2. Check ignition timing with a timing light.
OK or NG
OK >>INSPECTION END
NG >> GO TO 11.
11 . PERFORM ACCELERATOR PEDAL RELEASED POSITION LEARNING
1. Stop engine.
2. Perform EC-49, "
Accelerator Pedal Released Position Learning" .
>> GO TO 12.
12. PERFORM THROTTLE VALVE CLOSED POSITION LEARNING
Perform EC-49, "
Throttle Valve Closed Position Learning" .
>> GO TO 13.
13. PERFORM IDLE AIR VOLUME LEARNING
Refer to EC-49, "
Idle Air Volume Learning" .
Is Idle Air Volume Learning carried out successfully?
Ye s o r N o
Yes >> GO TO 14.
No >> 1. Follow the instruction of Idle Air Volume Learning.
2. GO TO 4.
14. CHECK TARGET IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Read idle speed in “DATA MONITOR” mode with CONSULT-II.
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
OK or NG
OK >> GO TO 15.
NG >> GO TO 17.15 ± 5° BTDC (in P or N position)
PBIB1602E
650 ± 50 rpm (in P or N position)
650 ± 50 rpm (in P or N position)
SEF174Y
TROUBLE DIAGNOSIS
EC-87
[VQ35DE]
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2004 November 2004 FX35/FX45
15. CHECK IGNITION TIMING AGAIN
1. Run engine at idle.
2. Check ignition timing with a timing light.
OK or NG
OK >>INSPECTION END
NG >> GO TO 16.
16. CHECK TIMING CHAIN INSTALLATION
Check timing chain installation. Refer to EM-63, "
TIMING CHAIN" .
OK or NG
OK >> GO TO 17.
NG >> 1. Repair the timing chain installation.
2. GO TO 4.
17. DETECT MALFUNCTIONING PART
Check the following.
Check camshaft position sensor (PHASE) and circuit. Refer to EC-308 .
Check crankshaft position sensor (POS) and circuit. Refer to EC-302 .
OK or NG
OK >> GO TO 18.
NG >> 1. Repair or replace.
2. GO TO 4.
18. CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of an incident, but
this is a rare case.)
2. Perform initialization of IVIS (NATS) system and registration of IVIS (NATS) ignition key IDs. Refer to EC-
68, "IVIS (Infiniti Vehicle Immobilizer System — NATS)" .
>> GO TO 4. 15 ± 5° BTDC (in P or N position)
PBIB1602E
EC-118
[VQ35DE]
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
DATA MONITOR (SPEC) MODE
Monitored Item
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
ACTIVE TEST MODE
Test Item
Voltage [V]
Voltage, frequency, duty cycle or pulse
width measured by the probe.
Only # is displayed if item is unable
to be measured.
Figures with #s are temporary ones.
They are the same figures as an
actual piece of data which was just
previously measured. Frequency [msec],
[Hz] or [%]
DUTY-HI
DUTY-LOW
PLS WIDTH-HI
PLS WIDTH-LOWMonitored item [Unit]ECM
INPUT
SIG-
NALSMAIN
SIG-
NALSDescription Remarks
Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
ENG SPEED [rpm]××
Indicates the engine speed computed
from the signal of the crankshaft position
sensor (POS) and camshaft position
sensor (PHASE).
MAS A/F SE-B1 [V]××
The signal voltage of the mass air flow
sensor specification is displayed.When engine is running specification
range is indicated.
B/FUEL SCHDL
[msec]×
Base fuel schedule indicates the fuel
injection pulse width programmed into
ECM, prior to any learned on board cor-
rection.
When engine is running specification
range is indicated.
A/F ALPHA-B1 [%]
A/F ALPHA-B2 [%]×
The mean value of the air-fuel ratio feed-
back correction factor per cycle is indi-
cated.When engine is running specification
range is indicated.
This data also includes the data for the
air-fuel ratio learning control.
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJEC-
TION
Engine: Return to the original
trouble condition
Change the amount of fuel injec-
tion using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.
Harness and connectors
Fuel injector
Heated oxygen sensor 1
IGNITION TIM-
ING
Engine: Return to the original
trouble condition
Timing light: Set
Retard the ignition timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.
Perform Idle Air Volume Learning.
POWER BAL-
ANCE
Engine: After warming up, idle
the engine.
A/C switch: OFF
Shift lever: P or N
Cut off each injector signal one at
a time using CONSULT-II.Engine runs rough or dies.
Harness and connectors
Compression
Fuel injector
Power transistor
Spark plug
Ignition coil
EC-256
[VQ35DE]
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
Revision: 2004 November 2004 FX35/FX45
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTIONPFP:16600
On Board Diagnosis LogicABS006OY
With the Air-Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The
ECM calculates the necessary compensation to correct the offset between the actual and the theoretical
ratios.
In case the amount of the compensation value is extremely large (the actual mixture ratio is too lean.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC Confirmation ProcedureABS006OZ
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.
WITH CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-II.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Select “DATA MONITOR” mode with CONSULT-II.
6. Start engine again and let it idle for at least 10 minutes.
The 1st trip DTC P0171 or P0174 should be detected at this
stage, if a malfunction exists. If so, go to Diagnostic Procedure,
EC-260
.
7. If it is difficult to start engine at step 6, the fuel injection system
has a malfunction, too.
8. Crank engine while depressing accelerator pedal. If engine
starts, go to EC-260, "
Diagnostic Procedure" . If engine does not
start, check exhaust and intake air leak visually.
Sensor Input signal to ECM ECM function Actuator
Heated oxygen sensor 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)Fuel injection
controlFuel injector
DTC No.Trouble diagnosis
nameDTC detecting condition Possible cause
P0171
0171
(Bank 1)
Fuel injection system
too lean
Fuel injection system does not operate properly.
The amount of mixture ratio compensation is too
large. (The mixture ratio is too lean.)
Intake air leaks
Heated oxygen sensor 1
Fuel Injector
Exhaust gas leaks
Incorrect fuel pressure
Lack of fuel
Mass air flow sensor
Incorrect PCV hose connection P0174
0174
(Bank 2)
SEF968Y
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-265
[VQ35DE]
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2004 November 2004 FX35/FX45
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTIONPFP:16600
On Board Diagnosis LogicABS006P2
With the Air-Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The
ECM calculates the necessary compensation to correct the offset between the actual and the theoretical
ratios.
In case the amount of the compensation value is extremely large (the actual mixture ratio is too rich.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC Confirmation ProcedureABS006P3
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.
WITH CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-II.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Select “DATA MONITOR” mode with CONSULT-II.
6. Start engine again and let it idle for at least 10 minutes.
The 1st trip DTC P0172, P0175 should be detected at this stage,
if a malfunction exists. If so, go to EC-269, "
Diagnostic Proce-
dure" .
7. If it is difficult to start engine at step 6, the fuel injection system
has a malfunction, too.
8. Crank engine while depressing accelerator pedal.
If engine starts, go to EC-269, "
Diagnostic Procedure" . If engine
does not start, remove spark plugs and check for fouling, etc.
Sensor Input signal to ECM ECM function Actuator
Heated oxygen sensor 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)Fuel injection
controlFuel injector
DTC No.Trouble diagnosis
nameDTC detecting condition Possible cause
P0172
0172
(Bank 1)
Fuel injection system
too rich
Fuel injection system does not operate properly.
The amount of mixture ratio compensation is too
large. (The mixture ratio is too rich.)
Heated oxygen sensor 1
Fuel injector
Exhaust gas leaks
Incorrect fuel pressure
Mass air flow sensor P0175
0175
(Bank 2)
SEF968Y
EC-350
[VQ35DE]
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
Revision: 2004 November 2004 FX35/FX45
DTC Confirmation ProcedureABS009VX
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.
WITH CONSULT-II
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
3. Start engine and wait at least 40 seconds.
NOTE:
Do not depress accelerator pedal even slightly.
If 1st trip DTC is detected, go to EC-350, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnostic ProcedureABS00CHI
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground three screws on the body. Refer to EC-141, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
SEF194Y
PBIB2195E