
CVT
N
O P
Diagnosis Procedure
without CONSULT-III INFOID:0000000004305601
OBD-II SELF-DIAGNOSTIC PROCEDURE (WITH GST)
Refer to EC-1124, " Generic Scan Tool (GST) Function " .
REV LAMP (ON/OFF) — X
STRTR RLY OUT (ON/OFF) — — Starter relay
LUSEL SOL MON (ON/OFF) — —
STRTR RLY MON (ON/OFF) — — Starter relay
VDC ON (ON/OFF) X — Not mounted but displayed.
TCS ON (ON/OFF) X —
ABS ON (ON/OFF) X —
ACC ON (ON/OFF) X — Not mounted but displayed.
RANGE — X Indicates position is recognized by TCM. Indi-
cates a specific value required for control when
fail-safe function is activated.
M GEAR POS — X
Voltage (V) — — Displays the value measured by the voltage
probe.
Frequency (Hz) — —
The value measured by the pulse probe is dis-
played.
DUTY-HI (high) (%) — —
DUTY-LOW (low) (%) — —
PLS WIDTH-HI (ms) — —
PLS WIDTH-LOW (ms) — — Monitored item (Unit)
Monitor item selection
Remarks
ECU IN-
PUT SIG- NALS MAIN SIG-
NALS SELEC-
TION
FROM
MENU

CVT
N
O P
DTC P0730 BELT DAMAGE
Description INFOID:0000000004305662
TCM selects the gear ratio using the engine load (throttle position), the primary pulley revolution speed, and
the secondary pulley revolution speed as input signal. T hen it changes the operating pressure of the primary
pulley and the secondary pulley and changes the groove width of the pulley.
CONSULT-III Reference Val ue in Data Monitor Mode INFOID:0000000004305663
Remarks: Specification data are reference values.
On Board Diagnosis Logic INFOID:0000000004305664
• This is not an OBD-II self-diagnostic item.
• TCM calculates the actual gear ratio with input speed sensor (primary speed sensor) and output speed sen-
sor (secondary speed sensor).
• Diagnostic trouble code “P0730 BELT DAMG” with CONSUL T-III is detected, when TCM receives an unex-
pected gear ratio signal.
Possible Cause INFOID:0000000004305665
Transaxle assembly
DTC Confirmation Procedure INFOID:0000000004305666
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, alw ays turn ignition switch OFF and
wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Turn ignition switch ON and select “DATA MO NITOR” mode for “TRANSMISSION” with CONSULT-III.
2. Make sure that output voltage of CVT fluid temperature sensor is within the range below.
ATF TEMP SEN: 1.0 - 2.0 V
If out of range, drive the vehicle to decrease the voltage (warm up the fluid) or stop engine to
increase the voltage (c ool down the fluid)
3. Select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
4. Start engine and maintain the following conditions for at least 30 consecutive seconds.
TEST START FROM 0 km/h (0 MPH)
CONSTANT ACCELERATION: Keep 30 sec or more
VEHICLE SPEED: 10 km/h (6 MPH) or more
ACC PEDAL OPEN: More than 1.0/8
RANGE: “D” position
ENG SPEED: 450 rpm or more
5. If DTC is detected, go to CVT-265, " Diagnosis Procedure " .
Diagnosis Procedure INFOID:0000000004305667DTC Confirmation Procedure " .
Are any DTC displayed? YES - 1>> DTC except for “P0730 BELT DAMG” is displa
yed: Go to Check the DTC detected item. Refer to
CVT-230, " CONSULT-III Function (TRANSMISSION) " .
YES - 2>> DTC for “P0730 BELT DAMG” is displayed: Replace the transaxle assembly. Refer to CVT-354," Removal and Installation " .
NO >> INSPECTION END
Item name Condition Display value (Approx.)
GEAR RATIO During driving 2.56 - 0.43

CVT
N
O P
DTC P0841 PRESSURE SENSOR FUNCTION
Description INFOID:0000000004305717
Using the engine load (throttle position), the primary pulley revolution speed, and the secondary pulley revolu-
tion speed as input signal, TCM changes the operating pr essure of the primary pulley and the secondary pul-
ley and changes the groove width of the pulley to control the gear ratio.
CONSULT-III Reference Val ue in Data Monitor Mode INFOID:0000000004305718
Remarks: Specification data are reference values.
On Board Diagnosis Logic INFOID:0000000004305719
• This is not an OBD-II self-diagnostic item.
• Diagnostic trouble code “P0841 PRESS SEN/FNCTN” with CONSULT-III is detected when secondary fluid
pressure is too high compared with the commanded value while driving.
Possible Cause INFOID:0000000004305720
• Transmission fluid pressure sensor A (Secondary pressure sensor)
• Harness or connectors
(Sensor circuit is open or shorted.)
DTC Confirmation Procedure INFOID:0000000004305721
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, alw ays turn ignition switch OFF and
wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Turn ignition switch ON and select “DATA MO NITOR” mode for “TRANSMISSION” with CONSULT-III.
2. Start engine and maintain the following conditions for at least 12 consecutive seconds. VEHICLE SPEED: 40 km/h (25 MPH) More than
RANGE: “D” position
3. If DTC is detected, go to CVT-291, " Diagnosis Procedure " .
Diagnosis Procedure INFOID:0000000004305722CONSULT-III Function (TRANSMISSION) " .
Is any malfunction of the “ U1000 CAN COMM CIRCUIT ” indicated?
YES >> Check CAN communication line. Refer to
CVT-238 .
NO >> GO TO 2.

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*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). T he amount of fuel injected is a program value in the
ECM memory. The program value is preset by engi ne operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from t he 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 compens ated 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 (A/T models)
• High-load, high-speed operation
• During deceleration
• During high engine speed operation
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system prov ides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can better reduce CO, HC and NOx emissions. This system uses A/F sen-
sor 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 si gnal. For more information about A/F sensor 1, refer to
EC-182, " Description " . This maintains the mixture ratio within t
he range of stoichiometric (ideal air-fuel mix-
ture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the th ree way catalyst (manifold). Even if the switching
characteristics of A/F sensor 1 shift, the air-fuel rati o is controlled to stoichiometric by the signal from heated
oxygen sensor 2.
• Open Loop Control
The open loop system condition refers to when the EC M 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 (A/T models)
- 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 cont rols the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mi xture ratio is not necessarily controlled as originally

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ELECTRIC IGNITION SYSTEM
System Diagram INFOID:0000000004780014
System Description INFOID:0000000004780015
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM via the CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION Ignition order: 1 - 3 - 4 - 2
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.
The ECM receives information such as the injecti on pulse width and camshaft position sensor (PHASE) sig-
nal. Computing this information, ignition si gnals are transmitted to the power transistor.
During the following conditions, the ignition timing is revi sed by the ECM according to the other data stored in
the ECM.
• At starting
• During warm-up
• At idle
• At low battery voltage
• During acceleration

Monitored item Unit Description Remarks
ENG SPEED rpm • Indicates the engine speed computed from the signal
of the crankshaft position sensor (POS) and camshaft
position sensor (PHASE). • Accuracy becomes poor if engine
speed drops below the idle rpm.
• If the signal is interrupted while the engine is running, an abnormal value
may be indicated.
MAS A/F SE-B1 V • The signal voltage of the mass air flow sensor is dis-
played. • When the engine is stopped, a certain
value is indicated.
• When engine is running specification range is indicated in “SPEC”.
B/FUEL SCHDL ms • “Base fuel schedule” indicates the fuel injection pulse
width programmed into ECM, prior to any learned on
board correction. • When engine is running specification
range is indicated in “SPEC”.
A/F ALPHA-B1 % • The mean value of the air-fuel ratio feedback correc-
tion factor per cycle is indicated. • When the engine is stopped, a certain
value is indicated.
• This data also includes the data for
the air-fuel ratio learning control.
• When engine is running specification range is indicated in “SPEC”.
COOLAN TEMP/S °C or °F • The engine coolant temperature (determined by the
signal voltage of the engine coolant temperature sen-
sor) is displayed. • When the engine coolant temperature
sensor is open or short-circuited,
ECM enters fail-safe mode. The en-
gine coolant temperature determined
by the ECM is displayed.
A/F SEN1 (B1) V • The A/F signal computed from the input signal of the
air fuel ratio (A/F) se nsor 1 is displayed.

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HO2S2 (B1) V
• The signal voltage of the heated oxygen sensor 2 is
displayed.
HO2S2 MNTR(B1) RICH/
LEAN • Display of heated oxygen sensor 2 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. • When the engine is stopped, a certain
value is indicated.
VHCL SPEED SE km/h or
mph • The vehicle speed computed from the vehicle speed
signal sent from combination meter is displayed.
BATTERY VOLT V • The power supply voltage of ECM is displayed.
ACCEL SEN 1 V• The accelerator pedal position sensor signal voltage is
displayed. • ACCEL SEN 2 signal is converted by
ECM internally. Thus, it differs from
ECM terminal voltage signal.
ACCEL SEN 2
TP SEN 1-B1 V• The throttle position sensor signal voltage is dis-
played. • TP SEN 2-B1 signal is converted by
ECM internally. Thus, it differs from
ECM terminal voltage signal.
TP SEN 2-B1
FUEL T/TMP SE °C or °F • The fuel temperature (determined by the signal volt-
age of the fuel tank temperature sensor) is displayed.
INT/A TEMP SE °C or °F • The intake air temperature (determined by the signal
voltage of the intake air temperature sensor) is indicat-
ed.
EVAP SYS PRES V • The signal voltage of EVAP control system pressure
sensor is displayed.
FUEL LEVEL SE V • The signal voltage of the fuel level sensor is displayed.
START SIGNAL ON/OFF • Indicates start signal status [ON/OFF] computed by
the ECM according to the signals of engine speed and
battery voltage. • After starting the engine, [OFF] is dis-
played regardless of the starter sig-
nal.
CLSD THL POS ON/OFF • Indicates idle position [ON/OFF] computed by ECM
according to the accelerator pedal position sensor sig-
nal.
AIR COND SIG ON/OFF • Indicates [ON/OFF] condition of the air conditioner
switch determined by the air conditioner ON signal.
P/N POSI SW ON/OFF • Indicates [ON/OFF] condit
ion from the park/neutral
position (PNP) switch signal.
PW/ST SIGNAL ON/OFF • [ON/OFF] condition of the power steering system (de-
termined by the signal sent from EPS control unit) is
indicated.
LOAD SIGNAL ON/OFF • Indicates [ON/OFF] condition from the electrical load
signal.
ON: Rear window defogger switch is ON and/or light-
ing switch is in 2nd position.
OFF: Both rear window defogger switch and lighting
switch are OFF.
IGNITION SW ON/OFF • Indicates [ON/OFF] condition from ignition switch sig-
nal.
HEATER FAN SW ON/OFF • Indicates [ON/OFF] condition from the heater fan
switch signal.
BRAKE SW ON/OFF • Indicates [ON/OFF] condition from the stop lamp
switch signal.
INJ PULSE-B1 msec • Indicates the actual fuel injection pulse width compen-
sated by ECM according to the input signals. • When the engine is stopped, a certain
computed value is indicated.
IGN TIMING BTDC • Indicates the ignition timing computed by ECM ac-
cording to the input signals. • When the engine is stopped, a certain
value is indicated.
CAL/LD VALUE % • “Calculated load value” indicates the value of the cur-
rent air flow divided by peak air flow.
Monitored item Unit Description Remarks
![NISSAN LATIO 2009 Service Repair Manual EC-520< SERVICE INFOMATION >
[MR TYPE 1]
ENGINE CONTROL SYSTEM
The mixture ratio feedback system provides the best air/ fuel mixture ratio for driveability and emission control.
The three way catal NISSAN LATIO 2009 Service Repair Manual EC-520< SERVICE INFOMATION >
[MR TYPE 1]
ENGINE CONTROL SYSTEM
The mixture ratio feedback system provides the best air/ fuel mixture ratio for driveability and emission control.
The three way catal](/manual-img/5/57359/w960_57359-1875.png)
EC-520< SERVICE INFOMATION >
[MR TYPE 1]
ENGINE CONTROL SYSTEM
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 r educe CO, HC and NOx emissions. This system uses air
fuel ratio (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 t he sensor voltage signal. For more information about air
fuel ratio (A/F) sensor 1, refer to EC-698 . 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 th ree way catalyst (manifold). Even if the switching
characteristics of air fuel ratio (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 EC M 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 air fuel ratio (A/F) sensor 1 or its circuit
• Insufficient activation of air fuel ratio (A /F) sensor 1 at low engine coolant temperature
• High engine coolant temperature
• During warm-up
• After shifting from N to D (A/T and CVT models)
• When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixt ure ratio signal transmitted from air fuel ratio (A/F)
sensor 1. 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 bas ic mixture ratio is not necessarily controlled as orig-
inally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during 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 co mpared 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 compensati on used to maintain the mixture ratio at its theoretical
value. The signal from air fuel ratio (A/F) sensor 1 i ndicates whether the mixture ratio is RICH or LEAN com-
pared to the theoretical value. The signal then triggers a r eduction 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 carri ed out long-term to compensate for continual deviation
of the short term fuel trim from t he central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycl e according to the firing order. This system is used
when the engine is running.
Simultaneous Multiport Fuel Injection System
Fuel is injected simultaneously into all four cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The four fuel injectors will then receive the signals two times for each engine cycle. SEF337W