2001 INFINITI QX4 turn signal

System DescriptionNBEC0015S02
SEF742M
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of
the engine. The ignition timing data is stored in the ECM. This data forms the map shown.
The ECM receives information such as the injection pulse width and camshaft position sensor signal. Com-
puting this information, ignition signals are transmitted to the power transistor.
e.g., N: 1,800 rpm, Tp: 1.50 msec
A ÉBTDC
During the following conditions, the ignition timing is revised by the ECM according to the other data stored
in the ECM.
IAt starting
IDuring warm-up
IAt idle
IAt low battery voltage
IDuring acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
Air Conditioning Cut Control
DESCRIPTIONNBEC0016Input/Output Signal ChartNBEC0016S01
Sensor Input Signal to ECM ECM function Actuator
Air conditioner switch Air conditioner ªONº signal
Air conditioner
cut controlAir conditioner relay Throttle position sensor Throttle valve opening angle
Crankshaft position sensor (POS) Engine speed (POS signal)
Crankshaft position sensor (REF) Engine speed (REF signal)
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Vehicle speed sensor Vehicle speed
Refrigerant pressure sensor Refrigerant pressure
Power steering oil pressure switch Power steering operation
System DescriptionNBEC0016S02This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned off.
IWhen the accelerator pedal is fully depressed.
IWhen cranking the engine.
IAt high engine speeds.
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ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
Electronic Ignition (EI) System (Cont'd)
EC-31

25 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1) SIGNAL
With CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front) (bank 1).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. See ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode.
6. Maintaining engine at 2,000 rpm under no-load (engine is warmed up to normal operating temperature.), check that the
monitor fluctuates between ªLEANº and ªRICHº more than 5 times during 10 seconds.
1 time: RICH®LEAN®RICH
2 times: RICH®LEAN®RICH®LEAN®RICH
Without CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front) (bank 1).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. Set voltmeter probe between ECM terminal 63 and ground.
6. Make sure that the voltage fluctuates between 0 - 0.3V and 0.6 - 1.0V more than 5 times during 10 seconds at 2,000
rpm.
1 time: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V
2 times: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V®0.6 - 1.0V®0 - 0.3V
OK or NG
OK©INSPECTION END
NG©GO TO 26.
26 DETECT MALFUNCTIONING PART
Check the following.
ICheck fuel pressure regulator. Refer to EC-40.
ICheck mass air flow sensor and its circuit. Refer to EC-150.
ICheck injector and its circuit. Refer to EC-616.
Clean or replace if necessary.
ICheck engine coolant temperature sensor and its circuit. Refer to EC-187.
ICheck ECM function by substituting another known-good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
©GO TO 3.
27 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1) HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect heated oxygen sensor 1 (front) (bank 1) harness connector.
4. Check harness continuity between ECM terminal 63 and heated oxygen sensor 1 (front) RH harness connector terminal
1.
Refer to Wiring Diagram, EC-196.
Continuity should exist.
OK or NG
OK©GO TO 30.
NG©GO TO 29.
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BASIC SERVICE PROCEDURE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-53

Items
(CONSULT-II screen terms)DTC*1 SRT codeTest value/ Test
limit
(GST only)1st trip DTC*1 Reference page
INTK TIM S/CIRC-B2 P1145 Ð Ð X EC-482
CLOSED LOOP-B1 P1148 Ð Ð X EC-491
SWL CON VC SW/CIRC P1165 Ð Ð X EC-493
CLOSED LOOP-B2 P1168 Ð Ð X EC-491
ENG OVER TEMP P1217 Ð Ð X LC-24
IGN SIGNAL-PRIMARY P1320 Ð Ð X EC-499
CPS/CIRCUIT (REF) P1335 Ð Ð X EC-510
CPS/CIRC (POS) COG P1336 Ð Ð X EC-517
EVAP VERY SMALL LEAK P1441 X X X*2 EC-526
PURG VOLUME CONT/V P1444 Ð Ð X EC-541
VENT CONTROL VALVE P1446 Ð Ð X EC-553
EVAP PURG FLOW/MON P1447 X X X*2 EC-561
VENT CONTROL VALVE P1448 Ð Ð X EC-573
FUEL LEVEL SEN/CIRC P1464 Ð Ð X EC-582
VC/V BYPASS/V P1490 Ð Ð X EC-585
VC CUT/V BYPASS/V P1491 Ð Ð X EC-591
A/T DIAG COMM LINE P1605 Ð Ð X EC-603
TP SEN/CIRC A/T P1705 Ð Ð X AT-218
P-N POS SW/CIRCUIT P1706 Ð Ð X EC-604
O/R CLTCH SOL/CIRC P1760 Ð Ð X AT-223
*1: 1st trip DTC No. is the same as DTC No.
*2: These are not displayed with GST.
NOTE:
Regarding R50 models, ª-B1º and ªBK1º indicate right bank and ª-B2º and ªBK2º indicate left bank.
HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATIONNBEC0031S06How to Erase DTC (With CONSULT-II)NBEC0031S0601NOTE:
If the DTC is not for A/T related items (see EC-8), skip steps 2 through 4.
1. If the ignition switch stays ªONº after repair work, be sure to turn ignition switch ªOFFº once. Wait at least
10 seconds and then turn it ªONº (engine stopped) again.
2. Turn CONSULT-II ªONº and touch ªA/Tº.
3. Touch ªSELF-DIAG RESULTSº.
4. Touch ªERASEº. [The DTC in the TCM (Transmission control module) will be erased.] Then touch ªBACKº
twice.
5. Touch ªENGINEº.
6. Touch ªSELF-DIAG RESULTSº.
7. Touch ªERASEº. (The DTC in the ECM will be erased.)
IIf DTCs are displayed for both ECM and TCM (Transmission control module), they need to be erased
individually from the ECM and TCM (Transmission control module).
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Emission-related Diagnostic Information (Cont'd)
EC-72

DATA MONITOR MODE=NBEC0034S06
Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
ENG SPEED [rpm]qqIIndicates the engine speed computed
from the REF signal (120É signal) of the
crankshaft position sensor (REF).
CKPS´RPM (POS)
[rpm]qIIndicates the engine speed computed
from the POS signal (1É signal) of the
crankshaft position sensor (POS).IAccuracy becomes poor if engine
speed drops below the idle rpm.
IIf the signal is interrupted while the
engine is running, an abnormal value
may be indicated.
POS COUNTqIIndicates the number of signal plate
(Flywheel/Drive Plate) cogs (tooth) dur-
ing one revolution of the engine.
MAS A/F SE-B1 [V]qqIThe signal voltage of the mass air flow
sensor is displayed.IWhen the engine is stopped, a certain
value is indicated.
COOLAN TEMP/S
[ÉC] or [ÉF]qqIThe engine coolant temperature (deter-
mined by the signal voltage of the
engine coolant temperature sensor) is
displayed.IWhen the engine coolant temperature
sensor is open or short-circuited, ECM
enters fail-safe mode. The engine cool-
ant temperature determined by the
ECM is displayed.
HO2S1 (B1) [V]qq
IThe signal voltage of the front heated
oxygen sensor is displayed.
HO2S1 (B2) [V]qq
HO2S2 (B1) [V]qq
IThe signal voltage of the rear heated
oxygen sensor is displayed.
HO2S2 (B2) [V]qq
HO2S1 MNTR (B1)
[RICH/LEAN]qIDisplay of front heated oxygen sensor
signal during air-fuel ratio feedback
control:
RICH ... means the mixture became
ªrichº, and control is being affected
toward a leaner mixture.
LEAN ... means the mixture became
ªleanº, and control is being affected
toward a rich mixture.IAfter turning ON the ignition switch,
ªRICHº is displayed until air-fuel mixture
ratio feedback control begins.
IWhen the air-fuel ratio feedback is
clamped, the value just before the
clamping is displayed continuously. HO2S1 MNTR (B2)
[RICH/LEAN]q
HO2S2 MNTR (B1)
[RICH/LEAN]qIDisplay of rear heated oxygen sensor
signal:
RICH ... means the amount of oxygen
after three way catalyst is relatively
small.
LEAN ... means the amount of oxygen
after three way catalyst is relatively
large.IWhen the engine is stopped, a certain
value is indicated.
HO2S2 MNTR (B2)
[RICH/LEAN]q
VHCL SPEED SE
[km/h] or [mph]qqIThe vehicle speed computed from the
vehicle speed sensor signal is dis-
played.
BATTERY VOLT [V]qqIThe power supply voltage of ECM is
displayed.
THRTL POS SEN [V]qqIThe throttle position sensor signal volt-
age is displayed.
FUEL T/TMP SE
[ÉC] or [ÉF]IThe fuel temperature judged from the
tank fuel temperature sensor signal
voltage is displayed.GI
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-87

Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
A/F ALPHA-B1 [%]q
IIndicates the mean value of the air-fuel ratio
feedback correction factor per cycle.IWhen the engine is running, specifi-
cation range is indicated.
IThis data also includes the data for
the air-fuel ratio learning control. A/F ALPHA-B2 [%]q
NOTE:
IAny monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
IRegarding R50 model, ªB1º indicates bank 1 and ªB2º indicates bank 2.
ACTIVE TEST MODENBEC0034S07
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJECTIONIEngine: Return to the original
trouble condition
IChange the amount of fuel injec-
tion using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IHarness and connector
IFuel injectors
IHeated oxygen sensor
IGNITION TIMINGIEngine: Return to the original
trouble condition
ITiming light: Set
IRetard the ignition timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IAdjust initial ignition timing
IACV-AAC/V
OPENINGIEngine: After warming up, idle
the engine.
IChange the IACV-AAC valve
opening percent using CON-
SULT-II.Engine speed changes according
to the opening percent.IHarness and connector
IIACV-AAC valve
POWER BAL-
ANCEIEngine: After warming up, idle
the engine.
IA/C switch ªOFFº
IShift lever ªNº
ICut off each injector signal one
at a time using CONSULT-II.Engine runs rough or dies.IHarness and connector
ICompression
IInjectors
IPower transistor
ISpark plugs
IIgnition coils
ENG COOLANT
TEMPIEngine: Return to the original
trouble condition
IChange the engine coolant tem-
perature using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IHarness and connector
IEngine coolant temperature sen-
sor
IFuel injectors
FUEL PUMP
RELAYIIgnition switch: ON
(Engine stopped)
ITurn the fuel pump relay ªONº
and ªOFFº using CONSULT-II
and listen to operating sound.Fuel pump relay makes the operat-
ing sound.IHarness and connector
IFuel pump relay
VIAS SOL VALVEIIgnition switch: ON
ITurn solenoid valve ªONº and
ªOFFº with CONSULT-II and lis-
ten for operating sound.Solenoid valve makes an operating
sound.IHarness and connector
ISolenoid valve
SWIRL CONT
S O L VA LV EIIgnition switch: ON
ITurn solenoid valve ªONº and
ªOFFº with CONSULT-II and lis-
ten for operating sound.Solenoid valve makes an operating
sound.IHarness and connector
ISolenoid valve
PURG VOL
CONT/VIEngine: After warming up, run
engine at 1,500 rpm.
IChange the EVAP canister purge
volume control solenoid valve
opening percent using CON-
SULT-II.Engine speed changes according
to the opening percent.IHarness and connector
ISolenoid valve
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-91

11 CHECK THROTTLE POSITION SWITCH CLOSED POSITION-II
With CONSULT-II
1. Turn ignition switch ªONº.
2. Select ªTP SW/TP SEN IDLE POSI ADJº in ªWORK SUPPORTº mode with CONSULT-II.
3. Read ªCLSD THL/P SWº signal under the following conditions.
IInsert a 0.05 mm (0.0020 in) and 0.15 mm (0.0059 in) feeler gauge alternately between stopper and throttle drum as
shown in the figure and check the signal.
SEF953Y
SEF987Y
ªCLSD THL/P SWº signal should remain ªONº while inserting 0.05 mm (0.0020 in) feeler gauge.
ªCLSD THL/P SWº signal should remain ªOFFº while inserting 0.15 mm (0.0059 in) feeler gauge.
OK or NG
OK©GO TO 14.
NG©GO TO 12.
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TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Basic Inspection (Cont'd)
EC-105

12 ADJUSTMENT THROTTLE POSITION SWITCH CLOSED POSITION-I
With CONSULT-II
1. Loosen throttle position sensor fixing bolts.
2. Confirm that proper vacuum is applied. Refer to test No. 10. During adjustment, vacuum should be applied.
3. Insert 0.05 mm (0.0020 in) feeler gauge between stopper and throttle drum as shown in the figure.
SEF953Y
4. Turn throttle position sensor body counterclockwise until ªCLSD THL/P SWº signal switches to ªOFFº.
SEF954Y
SEF007Z
©GO TO 13.
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Basic Inspection (Cont'd)
EC-106

14 RESET THROTTLE POSITION SENSOR IDLE POSITION MEMORY
With CONSULT-II
NOTE:
Always warm up engine to normal operating temperature. If engine is cool, the throttle position sensor idle posi-
tion memory will not be reset correctly.
1. Confirm that proper vacuum is applied. Refer to Test No. 10.
2. Attach blind cap to vacuum port from which vacuum hose to throttle opener was disconnected.
3. Start engine.
4. Warm up engine to normal operating temperature.
5. Select ªTP SW/TP SEN IDLE POSI ADJº in ªWORK SUPPORTº mode.
6. Stop engine. (Turn ignition switch ªOFFº.)
7. Turn ignition switch ªONº and wait at least 5 seconds.
SEF864V
8. Turn ignition switch ªOFFº and wait at least 10 seconds.
9. Repeat steps 7 and 8 until ªCLSD THL POSº signal changes to ªONº.
SEF987Y
©GO TO 19.
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Basic Inspection (Cont'd)
EC-108