IDX INFINITI QX4 2001 Factory Service Manual

P NO. INDEX FOR DTC=NBEC0001S02
DTC*1Items
(CONSULT-II screen terms)Reference page
Ð Unable to access ECM EC-117
P0000NO DTC IS DETECTED.
FURTHER TESTING
MAY BE REQUIRED.Ð
P0100 MAF SEN/CIRCUIT*3 EC-150
P0105 ABSL PRES SEN/CIRC EC-158
P0110 AIR TEMP SEN/CIRC EC-164
P0115 COOLANT T SEN/CIRC*3 EC-169
P0120 THRTL POS SEN/CIRC*3 EC-174
P0125 *COOLANT T SEN/CIRC EC-187
P0130 HO2S1 (B1) EC-192
P0131 HO2S1 (B1) EC-202
P0132 HO2S1 (B1) EC-210
P0133 HO2S1 (B1) EC-218
P0134 HO2S1 (B1) EC-231
P0135 HO2S1 HTR (B1) EC-240
P0137 HO2S2 (B1) EC-247
P0138 HO2S2 (B1) EC-257
P0139 HO2S2 (B1) EC-267
P0140 HO2S2 (B1) EC-277
P0141 HO2S2 HTR (B1) EC-286
P0150 HO2S1 (B2) EC-192
P0151 HO2S1 (B2) EC-202
P0152 HO2S1 (B2) EC-210
P0153 HO2S1 (B2) EC-218
P0154 HO2S1 (B2) EC-231
P0155 HO2S1 HTR (B2) EC-240
P0157 HO2S2 (B2) EC-247
P0158 HO2S2 (B2) EC-257
P0159 HO2S2 (B2) EC-267
P0160 HO2S2 (B2) EC-277
P0161 HO2S2 HTR (B2) EC-286
P0171 FUEL SYS-LEAN/BK1 EC-294
P0172 FUEL SYS-RICH/BK1 EC-302
P0174 FUEL SYS-LEAN/BK2 EC-294
P0175 FUEL SYS-RICH/BK2 EC-302
P0180 FUEL TEMP SEN/CIRC EC-309GI
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TROUBLE DIAGNOSIS Ð INDEX
Alphabetical & P No. Index for DTC (Cont'd)
EC-11

DTC*1Items
(CONSULT-II screen terms)Reference page
P0750 SFT SOL A/CIRC*3 AT-180
P0755 SFT SOL B/CIRC*3 AT-189
P1110 INT/V TIM CONT-B1 EC-446
P 1111INT/V TIM V/CIR-B1 EC-451
P1130 SWIRL CONT SOL/V EC-458
P1135 INT/V TIM CONT-B2 EC-446
P1136 INT/V TIM V/CIR-B2 EC-451
P1140 INTK TIM S/CIRC-B1 EC-482
P1145 INTK TIM S/CIRC-B2 EC-482
P1148 CLOSED LOOP-B1 EC-491
P1165 SWL CON VC SW/CIRC EC-493
P1168 CLOSED LOOP-B2 EC-491
P1217 ENG OVER TEMP LC-24
P1320 IGN SIGNAL-PRIMARY EC-499
P1335 CPS/CIRCUIT (REF) EC-510
P1336 CPS/CIRC (POS) COG EC-517
P1441 EVAP VERY SMALL LEAK EC-526
P1444 PURG VOLUME CONT/V EC-541
P1446 VENT CONTROL VALVE EC-553
P1447 EVAP PURG FLOW/MON EC-561
P1448 VENT CONTROL VALVE EC-573
P1464 FUEL LEVEL SEN/CIRC EC-582
P1490 VC/V BYPASS/V EC-585
P1491 VC CUT/V BYPASS/V EC-591
P1605 A/T DIAG COMM LINE EC-603
P1610 - P1615*2 NATS MALFUNCTION EL-328
P1705 TP SEN/CIRC A/T*3 AT-218
P1706 P-N POS SW/CIRCUIT EC-604
P1760 O/R CLTCH SOL/CIRC AT-223
*1: 1st trip DTC No. is the same as DTC No.
*2: This DTC is displayed with CONSULT-II only.
*3: When the fail-safe operation occurs, the MIL illuminates.
*4: The MIL illuminates when both the ªRevolution sensor signalº and the ªVehicle speed sensor signalº meet the fail-safe condition at
the same time.
NOTE:
IRegarding R50 models, ª-B1º and ªBK1º indicate right bank and ª-B2º and ªBK2º indicate left bank.
IBank 1 (-B1 or BK1) includes No. 1 cylinder.
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TROUBLE DIAGNOSIS Ð INDEX
Alphabetical & P No. Index for DTC (Cont'd)
EC-13

Engine Fuel & Emission Control SystemNBEC0004
SEF952RE
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PRECAUTIONS
Engine Fuel & Emission Control System
EC-15

SEF348N
IWhen measuring ECM signals with a circuit tester, never
allow the two tester probes to contact.
Accidental contact of probes will cause a short circuit and
damage the ECM power transistor.
IDo not use ECM ground terminals when measuring input/
output voltage. Doing so may result in damage to the
ECM's transistor. Use a ground other than the ECM
terminals, such as the ground.
SEF099WB
IRegarding model R50, ª-B1º indicates the right bank and
ª-B2º indicates the left bank as shown in the figure.
IBank 1 includes No. 1 cylinder.
Wiring Diagrams and Trouble DiagnosisNBEC0006When you read Wiring diagrams, refer to the following:
IGI-34, ªHOW TO READ WIRING DIAGRAMSº
IEL-9, ªPOWER SUPPLY ROUTINGº for power distribution circuit
When you perform trouble diagnosis, refer to the following:
IGI-38, ªHOW TO FOLLOW TEST GROUP IN TROUBLE DIAGNOSISº
IGI-34, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº
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PRECAUTIONS
Precautions (Cont'd)
EC-17

Tool name
(Kent-Moore No.)Description
Socket wrench
NT705
Removing and installing engine coolant tempera-
ture sensor
Oxygen sensor thread
cleaner
(J-43897-18)
(J-43897-12)
NT828
Reconditioning the exhaust system threads before
installing a new oxygen sensor. Use with anti-seize
lubricant shown below.
a: J-43897-18 18 mm diameter with pitch 1.5
mm, for Zirconia Oxygen Sensor
b: J-43897-12 12 mm diameter with pitch 1.25
mm, for Titania Oxygen Sensor
Anti-seize lubricant
(Permatex
TM133AR or
equivalent meeting MIL
specification MIL-A-907)
NT779
Lubricating oxygen sensor thread cleaning tool
when reconditioning exhaust system threads.
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PREPARATION
Commercial Service Tools (Cont'd)
EC-19

SEF034Z
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ENGINE AND EMISSION CONTROL OVERALL SYSTEM
Engine Control Component Parts Location (Cont'd)
EC-21

SEF036Z
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ENGINE AND EMISSION CONTROL OVERALL SYSTEM
Engine Control Component Parts Location (Cont'd)
EC-23

System DiagramNBEC0011
SEF930Y
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ENGINE AND EMISSION CONTROL OVERALL SYSTEM
System Diagram
EC-25

System ChartNBEC0013
Input (Sensor) ECM Function Output (Actuator)
ICamshaft position sensor (PHASE)
ICrankshaft position sensor (REF)
IMass air flow sensor
IEngine coolant temperature sensor
IHeated oxygen sensor 1 (front)
IIgnition switch
IThrottle position sensor
IClosed throttle position switch*3
IPark/neutral position (PNP) switch
IAir conditioner switch
IKnock sensor
IIntake air temperature sensor
IAbsolute pressure sensor
IEVAP control system pressure sensor*1
IBattery voltage
IPower steering oil pressure switch
IVehicle speed sensor
IFuel tank temperature sensor*1
ICrankshaft position sensor (POS)
IHeated oxygen sensor 2 (rear)*2
ITCM (Transmission control module)
IRefrigerant pressure sensor
IElectrical load
IFuel level sensor*1Fuel injection & mixture ratio control Injectors
Electronic ignition system Power transistor
Idle air control system IACV-AAC valve
Fuel pump control Fuel pump relay
On board diagnostic system MIL (On the instrument panel)
Swirl control valve controlSwirl control valve control solenoid
valve
Power valve control VIAS control solenoid valve
Heated oxygen sensor 1 heater (front) con-
trolHeated oxygen sensor 1 heater
(front)
Heated oxygen sensor 2 heater (rear) controlHeated oxygen sensor 2 heater
(rear)
EVAP canister purge flow controlEVAP canister purge volume con-
trol solenoid valve
Air conditioning cut control Air conditioner relay
ON BOARD DIAGNOSIS for EVAP systemIEVAP canister vent control valve
IVacuum cut valve bypass valve
*1: These sensors are not used to control the engine system. They are used only for the on board diagnosis.
*2: This sensor is not used to control the engine system under normal conditions.
*3: This switch will operate in place of the throttle position sensor to control EVAP parts if the sensor malfunctions.GI
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ENGINE AND EMISSION CONTROL OVERALL SYSTEM
System Chart
EC-27

Mixture Ratio Feedback Control (Closed loop control)NBEC0014S04
SEF336WA
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission con-
trol. The warm-up three way catalyst can then better reduce CO, HC and NOx emissions. This system uses
a heated oxygen sensor 1 (front) in the exhaust manifold to monitor if the engine operation is rich or lean. The
ECM adjusts the injection pulse width according to the sensor voltage signal. For more information about the
heated oxygen sensor 1 (front), refer to EC-192. This maintains the mixture ratio within the range of stoichio-
metric (ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 (rear) is located downstream of the warm-up three way catalyst. Even if the switch-
ing characteristics of the heated oxygen sensor 1 (front) shift, the air-fuel ratio is controlled to stoichiometric
by the signal from the heated oxygen sensor 2 (rear).
Open Loop ControlNBEC0014S05The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
IDeceleration and acceleration
IHigh-load, high-speed operation
IMalfunction of heated oxygen sensor 1 (front) or its circuit
IInsufficient activation of heated oxygen sensor 1 (front) at low engine coolant temperature
IHigh engine coolant temperature
IDuring warm-up
IAfter shifting from ªNº to ªDº
IWhen starting the engine
Mixture Ratio Self-learning ControlNBEC0014S06The mixture ratio feedback control system monitors the mixture ratio signal transmitted from the heated oxy-
gen sensor 1 (front). This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio
as close to the theoretical mixture ratio as possible. However, the basic mixture ratio is not necessarily con-
trolled as originally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and char-
acteristic changes during operation (i.e., injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This
is then computed in terms of ªinjection pulse durationº to automatically compensate for the difference between
the two ratios.
ªFuel trimº refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
ªShort term fuel trimº is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from the heated oxygen sensor 1 (front) indicates whether the mixture ratio is RICH or LEAN
compared to the theoretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is
rich, and an increase in fuel volume if it is lean.
ªLong term fuel trimº is overall fuel compensation carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
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ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
Multiport Fuel Injection (MFI) System (Cont'd)
EC-29