2001 INFINITI QX4 battery

DescriptionNBEC0249SYSTEM DESCRIPTIONNBEC0249S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed (POS signal)
Idle air
controlIACV-AAC valve Crankshaft position sensor (REF) Engine speed (REF signal)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Throttle position sensor Throttle position
Park/neutral position (PNP) switch Park/neutral position
Air conditioner switch Air conditioner operation
Power steering oil pressure switch Power steering load signal
Battery Battery voltage
Vehicle speed sensor Vehicle speed
Ambient air temperature switch Ambient air temperature
Intake air temperature sensor Intake air temperature
Absolute pressure sensor Ambient barometic pressure
This system automatically controls engine idle speed to a specified
level. Idle speed is controlled through fine adjustment of the
amount of air which by-passes the throttle valve via IACV-AAC
valve. The IACV-AAC valve changes the opening of the air by-pass
passage to control the amount of auxiliary air. This valve is actu-
ated by a step motor built into the valve, which moves the valve in
the axial direction in steps corresponding to the ECM output sig-
nals. One step of IACV-AAC valve movement causes the respec-
tive opening of the air by-pass passage. (i.e. when the step
advances, the opening is enlarged.) The opening of the valve is
varied to allow for optimum control of the engine idling speed. The
crankshaft position sensor (POS) detects the actual engine speed
and sends a signal to the ECM. The ECM then controls the step
position of the IACV-AAC valve so that engine speed coincides with
the target value memorized in ECM. The target engine speed is the
lowest speed at which the engine can operate steadily. The opti-
mum value stored in the ECM is determined by takig into consid-
eration various engine conditions, such as during warm up,
deceleration, and engine load (air conditioner, power steering and
cooling fan operation).
SEF765P
COMPONENT DESCRIPTIONNBEC0249S02IACV-AAC ValveNBEC0249S0201The IACV-AAC valve is operated by a step motor for centralized
control of auxiliary air supply. This motor has four winding phases
and is actuated by the output signals of ECM which turns ON and
OFF two windings each in seqeunce. Each time the IACV-AAC
valve opens or closes to change tha auxiliary air quantity, the ECM
sends a pulse signal to the step motor. When no change in the
auxiliary air quantity is needed, the ECM does not issue the pulse
signal. A certain voltage signal is issued so that the valve remains
at that particular opening.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
Description
EC-422

SEF058Y
PROCEDURE FOR MALFUNCTION ANBEC0253S01TESTING CONDITION:
Before performing the following procedure, confirm that bat-
tery voltage is more than 10.5V with ignition switch ªONº.
With CONSULT-IINBEC0253S01011) Start engine and warm it up to normal operating temperature.
2) Turn ignition switch ªOFFº and wait at least 10 seconds.
3) Perform ªIdle Air Volume Learningº (see EC-57).
4) Turn ignition switch ªOFFº and wait at least 10 seconds.
5) Turn ignition switch ªONº.
6) Select ªDATA MONITORº mode with CONSULT-II.
7) Start engine and let it idle.
8) Keep engine speed at 2,500 rpm for three seconds, then let it
idle for three seconds.
Do not rev engine to more than 3,000 rpm.
9) Perform step 4 once more.
10) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-426.
With GSTNBEC0253S0102Follow the procedure ªWith CONSULT-IIº above.
SEF174Y
PROCEDURE FOR MALFUNCTION BNBEC0253S02TESTING CONDITION:
IBefore performing the following procedure, confirm that
battery voltage is more than 11V at idle.
IAlways perform the test at a temperature above þ10ÉC
(14ÉF).
With CONSULT-IINBEC0253S02011) Open engine hood.
2) Start engine and warm it up to normal operating temperature.
3) Turn ignition switch ªOFFº and wait at least 10 seconds.
4) Perform ªIdle Air Volume Learningº (see EC-57).
5) Turn ignition switch ªOFFº and wait at least 10 seconds.
6) Turn ignition switch ªONº again and select ªDATA MONITORº
mode with CONSULT-II
7) Start engine and run it for at least 1 minute at idle speed.
8) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-426.
With GSTNBEC0253S0202Follow the procedure ªWith CONSULT-IIº above.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
DTC Confirmation Procedure (Cont'd)
EC-424

SEF505V
Component DescriptionNBEC0256A closed throttle position switch and wide open throttle position
switch are built into the throttle position sensor unit. The wide open
throttle position switch is used only for A/T control.
When the throttle valve is in the closed position, the closed throttle
position switch sends a voltage signal to the ECM. The ECM only
uses this signal to open or close the EVAP canister purge volume
control solenoid valve when the throttle position sensor is malfunc-
tioning.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0257Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
CLSD THL/P SWIEngine: After warming up, idle
the engineThrottle valve: Idle position ON
Throttle valve: Slightly open OFF
ECM Terminals and Reference ValueNBEC0671Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
56 OR/LThrottle position switch
(Closed position)[Engine is running]
IAccelerator pedal fully releasedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
IAccelerator pedal depressedApproximately 0V
On Board Diagnosis LogicNBEC0259Malfunction is detected when battery voltage from the closed
throttle position switch is sent to ECM with the throttle valve
opened.
Possible CauseNBEC0516IHarness or connectors
(The closed throttle position switch circuit is shorted.)
IClosed throttle position switch
IThrottle position sensor
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0510 CLOSED THROTTLE POSITION SWITCH
Component Description
EC-431

SEF197Y
SEF198Y
DTC Confirmation ProcedureNBEC0260CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
WITH CONSULT-IINBEC0260S011) Start engine and warm it up to normal operating temperature.
2) Turn ignition switch ªOFFº, wait at least 10 seconds and then
start engine.
3) Select ªCLSD THL/P SWº in ªDATA MONITORº mode.
If ªCLSD THL/P SWº is not available, go to step 5.
4) Check the signal under the following conditions.
Condition Signal indication
Throttle valve: Idle position ON
Throttle valve: Slightly open OFF
If the result is NG, go to ªDiagnostic Procedureº, EC-435.
If OK, go to following step.
5) Select ªDATA MONITORº mode with CONSULT-II.
6) Drive the vehicle for at least 5 consecutive seconds under the
following condition.
THRTL POS SEN More than 2.5V
VHCL SPEED SE More than 5 km/h (3 MPH)
Selector lever Suitable position
Driving locationDriving vehicle uphill (Increased engine load)
will help maintain the driving conditions
required for this test.
7) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-435.
SEF345X
Overall Function CheckNBEC0261Use this procedure to check the overall function of the closed
throttle position switch circuit. During this check, a 1st trip DTC
might not be confirmed.
WITH GSTNBEC0261S011) Start engine and warm it up to normal operating temperature.
2) Check the voltage between ECM terminal 56 (Closed throttle
position switch signal) and ground under the following condi-
tions.
At idle: Battery voltage
DTC P0510 CLOSED THROTTLE POSITION SWITCH
DTC Confirmation Procedure
EC-432

System DescriptionNBEC0264This circuit line (LAN) is used to control the smooth shifting up and down of A/T during the hard acceleration/
deceleration.
Pulse signals are exchanged between ECM and TCM (Transmission Control Module).
Be sure to erase the malfunction information such as DTC not only in TCM but also ECM after the A/T
related repair.
ECM Terminals and Reference ValueNBEC0672Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
114 G/RCommunication line
(LAN)[Engine is running]
IIdle speedApproximately 2V
On Board Diagnosis LogicNBEC0266Malfunction is detected when ECM receives incorrect voltage from
TCM (Transmission Control Module) continuously.
Possible CauseNBEC0517IHarness or connectors
[The communication line circuit between ECM and TCM
(Transmission Control Module) is open or shorted.]
ITCM
IDead (Weak) battery
SEF058Y
DTC Confirmation ProcedureNBEC0267NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that bat-
tery voltage is more than 10.5V at idle.
WITH CONSULT-IINBEC0267S011) Turn ignition switch ªONº.
DTC P0600 A/T COMMUNICATION LINE
System Description
EC-440

ECM Terminals and Reference Value=NBEC0693Specification data are reference values, and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring voltage. Doing so may result in damage to the
ECM's transistor. Use a ground other than the ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
13 OR/BIntake valve timing
control solenoid valves
(RH)[Engine is running]
IWarm-up condition
IIdle speedBattery voltage
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.7-8V
SEF350Z
15 P/LIntake valve timing
control solenoid valves
(LH)[Engine is running]
IWarm-up condition
IIdle speedBattery voltage
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.7-8V
SEF350Z
79 Y/GIntake valve timing
control position sen-
sors (RH)[Engine is running]
IWarm-up condition
IIdle speedApproximately 0.5VSEF351Z
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.Approximately 0.5V
SEF352Z
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P1110 (RIGHT, -B1), P1135 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
ECM Terminals and Reference Value
EC-447

SEF354Z
Component DescriptionNBEC0697Intake valve timing control solenoid valve is activated by ON/OFF
pulse duty (ratio) signals from the ECM.
The intake valve timing control solenoid valve changes the oil
amount and direction of flow through intake valve timing control unit
or stops oil flow.
The longer pulse width advances valve angle.
The shorter pulse width retards valve angle.
When ON and OFF pulse widths become equal, the solenoid valve
stops oil pressure flow to fix the intake valve angle at the control
position.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0698Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
INT/V SOL (B1)
INT/V SOL (B2)IEngine: After warming up
IShift lever ªNº
IQuickly depressed accelerator
pedal
INo-loadIdle 0%
2,000 rpm Approximately 40%
ECM Terminals and Reference ValueNBEC0699Specification data are reference values, and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than the ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
13 OR/BIntake valve timing
control solenoid valves
(RH)[Engine is running]
IWarm-up condition
IIdle speedBattery voltage
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.7-8V
SEF350Z
15 P/LIntake valve timing
control solenoid valves
(LH)[Engine is running]
IWarm-up condition
IIdle speedBattery voltage
[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.7-8V
SEF350Z
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
D T C P 1111(RIGHT, -B1), P1136 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
SOLENOID VALVE (CIRCUIT)
Component Description
EC-451

Diagnostic ProcedureNBEC0704
1 CHECK OVERALL FUNCTION
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Perform ªTARGET INT/V TIMº in ªACTIVE TESTº mode with CONSULT-II.
3. Hold engine speed at 1,500 to 2,500 rpm under the following step.
4. Touch ªUPº or ªDOWNº on CONSULT-II screen.
SEF355Z
5. Check the following.
IThe angle of a corresponding INT/V TIM (B1)/(B2) to setting TARGET INT/V TIM confirms the variation.
Without CONSULT-II
1. Remove intake valve timing control solenoid valve.
2. Reconnect intake valve timing control solenoid valve harness connector.
3. Supply intake valve timing control solenoid valve terminals with battery voltage as shown below.
SEF356Z
Clicking noise should be heard.
OK or NG
OK©INSPECTION END
NG©GO TO 2.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
D T C P 1111(RIGHT, -B1), P1136 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
SOLENOID VALVE (CIRCUIT)
Diagnostic Procedure
EC-455