2006 INFINITI M35 starting

DTC P0461 FUEL LEVEL SENSOR
EC-477
[VQ35DE]
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Revision: 2006 January2006 M35/M45
DTC P0461 FUEL LEVEL SENSORPFP:25060
Component DescriptionNBS0051E
The fuel level sensor is mounted in the fuel level sensor unit.
Fuel level sensor unit and fuel pump (1)
Fuel pressure regulator (2)
Fuel tank temperature sensor (3)
The sensor detects a fuel level in the fuel tank and transmits a signal
to the “unified meter and A/C amp.”. The “unified meter and A/C
amp.” sends the fuel level sensor signal to the ECM through CAN
communication line.
It consists of two parts, one is mechanical float and the other is vari-
able resistor. Fuel level sensor output voltage changes depending on
the movement of the fuel mechanical float.
On Board Diagnosis LogicNBS0051F
NOTE:
If DTC P0461 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-173, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
If DTC P0461 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010.
Refer to EC-176, "
DTC U1010 CAN COMMUNICATION" .
Driving long distances naturally affect fuel gauge level.
This diagnosis detects the fuel gauge malfunction of the gauge not moving even after a long distance has
been driven.
Overall Function CheckNBS0051G
Use this procedure to check the overall function of the fuel level sensor function. During this check, a 1st trip
DTC might not be confirmed.
WAR NING :
When performing following procedure, be sure to observe the handling of the fuel. Refer to FL-10,
"FUEL TANK" .
TESTING CONDITION:
Before starting overall function check, preparation of draining fuel and refilling fuel is required.
WITH CONSULT-II
NOTE:
Start from step 10, if it is possible to confirm that the fuel cannot be drained by 30 (7-7/8 US gal, 6-5/
8 Imp gal) in advance.
1. Prepare a fuel container and a spare hose.
2. Release fuel pressure from fuel line, refer to EC-98, "
FUEL PRESSURE RELEASE" .
3. Remove the fuel feed hose on the fuel level sensor unit.
4. Connect a spare fuel hose where the fuel feed hose was removed.
5. Turn ignition switch OFF and wait at least 10 seconds then turn ON.
PBIB2707E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0461
0461Fuel level sensor circuit
range/performanceThe output signal of the fuel level sensor does
not change within the specified range even
though the vehicle has been driven a long dis-
tance.
Harness or connectors
(The CAN communication line is open or
shorted)
Harness or connectors
(The sensor circuit is open or shorted)
Unified meter and A/C amp.
Fuel level sensor

EC-504
[VQ35DE]
DTC P0850 PNP SWITCH
Revision: 2006 January2006 M35/M45
DTC P0850 PNP SWITCHPFP:23006
Component DescriptionNBS0052M
When the selector lever position is P or N, park/neutral position (PNP) switch is ON.
ECM detects the position because the continuity of the line (the ON signal) exists.
CONSULT-II Reference Value in Data Monitor ModeNBS0052N
Specification data are reference values.
On Board Diagnosis LogicNBS0052O
DTC Confirmation ProcedureNBS0052P
CAUTION:
Always drive vehicle at a safe speed.
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 ON.
2. Select “P/N POSI SW” in “DATA MONITOR” mode with CON-
SULT-II. Then check the “P/N POSI SW” signal under the follow-
ing conditions.
If NG, go to EC-507, "
Diagnostic Procedure" .
If OK, go to following step.
3. Select “DATA MONITOR” mode with CONSULT-II.
4. Start engine and warm it up to normal operating temperature.
5. Maintain the following conditions for at least 50 consecutive sec-
onds.
6. If 1st trip DTC is detected, go to EC-507, "
Diagnostic Procedure" .
MONITOR ITEM CONDITION SPECIFICATION
P/N POSI SW
Ignition switch: ONSelector lever: P or N ON
Selector lever: Except above OFF
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0850
0850Park/neutral position
switchThe signal of the park/neutral position (PNP)
switch is not changed in the process of engine
starting and driving.
Harness or connectors
[The park/neutral position (PNP) switch
circuit is open or shorted.]
Park/neutral position (PNP) switch
Unified meter and A/C amp.
TCM
Position (Selector lever) Known-good signal
N or P position ON
Except above position OFF
SEF212Y
ENG SPEED 1,400 - 6,375 rpm
COOLAN TEMP/S More than 70
C (158F)
B/FUEL SCHDL 2.0 - 31.8 msec
VHCL SPEED SE More than 64 km/h (40 MPH)
Selector lever Suitable position
SEF213Y

DTC P0850 PNP SWITCH
EC-507
[VQ35DE]
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Revision: 2006 January2006 M35/M45
Specification 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.
Diagnostic ProcedureNBS0052S
1. CHECK DTC WITH TCM
Refer to AT- 4 0 , "
OBD-II Diagnostic Trouble Code (DTC)" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2. CHECK STARTING SYSTEM
Turn ignition switch OFF, then turn it to START.
Does starter motor operate?
Ye s o r N o
Ye s > > G O T O 3 .
No >> Refer to SC-10, "
STARTING SYSTEM" .
3. CHECK PNP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-I
1. Turn ignition switch OFF.
2. Disconnect A/T assembly harness connector.
3. Disconnect “unified meter and A/C amp.” harness connector.
4. Check harness continuity between A/T assembly terminal 9 and “unified meter and A/C amp.” terminal 2.
Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4. DETECT MALFUNCTIONING PART
Check the following.
Harness connectors M72, F102
Harness for open or short between A/T assembly and “unified meter and A/C amp.”
>> Repair open circuit or short to ground or short to power in harness or connectors.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
102 G PNP switch[Ignition switch: ON]
Selector lever: P or NApproximately 0V
[Ignition switch: ON]
Selector lever: Except aboveBATTERY VOLTAGE
(11 - 14V)
Continuity should exist.

EC-532
[VQ35DE]
DTC P1220 FUEL PUMP CONTROL MODULE (FPCM)
Revision: 2006 January2006 M35/M45
12. CHECK INTERMITTENT INCIDENT
Refer to EC-165, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionNBS0053G
FUEL PUMP CONTROL MODULE
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Check voltage between FPCM terminal 4 and ground under the
following conditions.
4. If NG, replace fuel pump control module.
: Vehicle front 1. FPCM 2. Dropping resistor
Condition Voltage
When engine cranking Approx. 0V
After starting engine Approx. 5V
PBIB2708E
PBIB0101E

SNOW MODE SWITCH
EC-717
[VQ35DE]
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Revision: 2006 January2006 M35/M45
SNOW MODE SWITCHPFP:25310
DescriptionNBS0058Q
NOTE:
If DTC U1000 or U1001 are displayed, first perform the trouble diagnosis for DTC U1000, U1001.
Refer to EC-173, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
The snow mode switch signal is sent to the “unified meter and A/C amp.” from the snow mode switch. The
“unified meter and A/C amp.” then sends the signal to the ECM by CAN communication line.
The snow mode is used for driving or starting the vehicle on snowy roads or slippery areas. If the snow mode
is activated, the vehicle speed will not be accelerated immediately than your original pedal in due to avoid the
vehicle slip. In other words, ECM controls the rapid engine torque change by controlling the electric throttle
control actuator operating speed.
CONSULT-II Reference Value in the Data Monitor ModeNBS0058R
MONITOR ITEM CONDITION SPECIFICATION
SNOW MODE SW
Ignition switch: ONSNOW MODE SW: ON ON
SNOW MODE SW: OFF OFF

PRECAUTIONS
EC-737
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Revision: 2006 January2006 M35/M45
Do not operate fuel pump when there is no fuel in lines.
–Fuel level sensor unit and fuel pump (1)
–Fuel pressure regulator (2)
–Fuel tank temperature sensor (3)
Tighten fuel hose clamps to the specified torque.
Do not depress accelerator pedal when starting.
Immediately after starting, do not rev up engine unneces-
sarily.
Do not rev up engine just prior to shutdown.
When installing C.B. ham radio or a mobile phone, be sure
to observe the following as it may adversely affect elec-
tronic control systems depending on installation location.
–Keep the antenna as far as possible from the electronic
control units.
–Keep the antenna feeder line more than 20 cm (8 in) away
from the harness of electronic controls.
Do not let them run parallel for a long distance.
–Adjust the antenna and feeder line so that the standing-
wave radio can be kept smaller.
–Be sure to ground the radio to vehicle body.
PBIB2707E
SEF709Y
SEF708Y

ENGINE CONTROL SYSTEM
EC-741
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Revision: 2006 January2006 M35/M45
Multiport Fuel Injection (MFI) SystemNBS0059J
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent to the ECM through CAN communication line.
*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). The amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from the crankshaft position sensor (POS), camshaft position
sensor (PHASE) and the mass air flow sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compensated to improve engine performance under various operat-
ing conditions as listed below.

During warm-up
When starting the engine
During acceleration
Hot-engine operation
When selector lever is changed from N to D
High-load, high-speed operation

During deceleration
During high engine speed operation
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
3
Piston position
Fuel injection
& mixture ratio
controlFuel injector Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/neutral position (PNP) switch Gear position
Battery
Battery voltage*
3
Knock sensor Engine knocking condition
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit)*
2VDC/TCS operation command
Air conditioner switch*
2Air conditioner operation
Wheel sensor*
2Vehicle speed

EC-742
[VK45DE]
ENGINE CONTROL SYSTEM
Revision: 2006 January2006 M35/M45
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better reduce CO, HC and NOx emissions. This system uses A/F
sensor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The ECM adjusts the
injection pulse width according to the sensor voltage signal. For more information about A/F sensor 1, refer to
EC-969
. This maintains the mixture ratio within the range of stoichiometric (ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the three way catalyst (manifold). Even if the switching
characteristics of A/F sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal from heated
oxygen sensor 2.
Open Loop Control
The 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.
Deceleration and acceleration
High-load, high-speed operation
Malfunction of A/F sensor 1 or its circuit
Insufficient activation of A/F sensor 1 at low engine coolant temperature
High engine coolant temperature
During warm-up
After shifting from N to D
When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic changes dur-
ing operation (i.e., fuel 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 “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from A/F sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the the-
oretical 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.
“Long term fuel trim” 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.
PBIB2793E