light NISSAN LATIO 2011 Service Manual Online

EC-96
< FUNCTION DIAGNOSIS >[HR16DE]
DIAGNOSIS SYSTEM (ECM)
DIAGNOSIS SYSTEM (ECM)
DIAGNOSIS DESCRIPTION
DIAGNOSIS DESCRIPTION : 1st Trip Detect
ion Logic and Two Trip Detection Logic
INFOID:0000000006314663
When a malfunction is detected for the first time, 1st tr ip DTC and 1st trip Freeze Frame data are stored in the
ECM memory. The MIL will not illuminate at this stage. <1st trip>
If the same malfunction is detected again during the next drive, the DTC and Freeze Frame data are stored in
the ECM memory, and the MIL illuminates. The MIL illuminates at the same time when the DTC is stored.
<2nd trip> The “trip” in the “Two Trip Detection Logic” means a driving mode in which self-diagnosis is per-
formed during vehicle operation. Specific on board diagnos tic items will cause the ECM to illuminate or blink
the MIL, and store DTC and Freeze Frame data, even in the 1st trip, as shown below.
× : Applicable —: Not applicable
DIAGNOSIS DESCRIPTION : DT C and Freeze Frame DataINFOID:0000000006314664
DTC AND 1ST TRIP DTC
The 1st trip DTC (whose number is the same as the DT C number) is displayed for the latest self-diagnostic
result obtained. If the ECM memory was cleared previously , and the 1st trip DTC did not recur, the 1st trip DTC
will not be displayed.
If a malfunction is detected during the 1st trip, the 1st trip DTC is saved in the ECM memory. The MIL will not
light up (two trip detection logic). If the same malfunction is not detected in the 2nd trip (meeting the required
driving pattern), the 1st trip DTC is cleared from the ECM memory. If the same malfunction is detected in the
2nd trip, both the 1st trip DTC and DTC are saved in the ECM memory and the MIL lights up. In other words,
the DTC is stored in the ECM memory and the MIL light s up when the same malfunction occurs in two consec-
utive trips. If a 1st trip DTC is stored and a non-diagnostic operation is performed between the 1st and 2nd
trips, only the 1st trip DTC will continue to be stored. Fo r malfunctions that blink or light up the MIL during the
1st trip, the DTC and 1st trip DTC are stored in the ECM memory.
For malfunctions in which 1st trip DTCs are displayed, refer to EC-478, "
DTCIndex". These items are
required by legal regulations to continuously monito r the system/component. In addition, the items monitored
non-continuously are also displayed on CONSULT-III.
1st trip DTC is specified in Service $07 of SAE J1979/ ISO 15031-5. 1st trip DTC detection occurs without illu-
minating the MIL and therefore does not warn the driver of a malfunction.
When a 1st trip DTC is detected, check, print out or write down and erase (1st trip) DTC and Freeze Frame
data as specified in Work Flow procedure Step 2, refer to EC-15, "
Work Flow". Then perform DTC Confirma-
tion Procedure or Component Function Check to try to duplicate the malfunction. If the malfunction is dupli-
cated, the item requires repair.
FREEZE FRAME DATA AND 1ST TRIP FREEZE FRAME DATA
The ECM records the driving conditions such as fuel system status, calculated load value, engine coolant tem-
perature, short term fuel trim, long term fuel trim, engine speed, vehicle speed, absolute throttle position, base
fuel schedule and intake air temperature at the moment a malfunction is detected.
Data which are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data.
The data, stored together with the DTC data, are called freeze frame data and displayed on CONSULT-III or
GST. The 1st trip freeze frame data can only be displayed on the CONSULT-III screen.
Items MIL
DTC1st trip DTC
1st trip 2nd trip
1st trip
displaying 2nd trip
displaying 1st trip
displaying 2nd trip
display- ing
Blinking Illuminat-
ed Blinking Illuminat-
ed
Misfire (Possible three way catalyst
damage) — DTC: P0300 - P0304 is
being detected ×
———— — ×—
Misfire (Possible three way catalyst
damage) — DTC: P0300 - P0304 is
being detected ——
×—— ×——
One trip detection diagnoses (Re-
fer to EC-478, "
DTCIndex".) —
×—— ×———
Except above — — —×— ×× —
Revision: May 2010 2011 Versa

EC-98
< FUNCTION DIAGNOSIS >[HR16DE]
DIAGNOSIS SYSTEM (ECM)
Explanation for Driving Patterns for “Misfire ”, “Fuel Injection System”
Driving Pattern B
Refer to
EC-100, "DIAGNOSIS DESCRIPTION : Driving Pattern".
*1: When the same malfunction is de-
tected in two consecutive trips, MIL
will light up. *2: MIL will turn OFF after vehicle is driv-
en 3 times (pattern B) without any
malfunctions. *3: When the same malfunction is de-
tected in two consecutive trips, the
DTC and the freeze frame data will be
stored in ECM.
*4: The DTC and the freeze frame data will not be displayed any longer after
vehicle is driven 80 times (pattern C)
without the same malfunction. (The
DTC and the freeze frame data still
remain in ECM.) *5: When a malfunction is detected for
the first time, the 1st trip DTC and the
1st trip freeze frame data will be
stored in ECM. *6: The 1st trip DTC and the 1st trip
freeze frame data will be cleared at
the moment OK is detected.
*7: When the same malfunction is de- tected in the 2nd trip, the 1st trip
freeze frame data will be cleared. *8: 1st trip DTC will
be cleared when ve-
hicle is driven once (pattern C) with-
out the same malfunction after DTC
is stored in ECM.
JMBIA1417GB
Revision: May 2010 2011 Versa

EC-100
< FUNCTION DIAGNOSIS >[HR16DE]
DIAGNOSIS SYSTEM (ECM)
Explanation for Driving Patterns Except for “Misfire
”, “Fuel Injection
System”
Driving Pattern A
Refer to EC-100, "DIAGNOSIS DESCRIPTION : Driving Pattern".
Driving Pattern B
Refer to EC-100, "DIAGNOSIS DESCRIPTION : Driving Pattern".
DIAGNOSIS DESCRIPTION : Driving PatternINFOID:0000000006314666
CAUTION:
Always drive at a safe speed.
DRIVING PATTERN A
Driving pattern A means a trip satisfying the following conditions.
• Engine speed reaches 400 rpm or more.
• Engine coolant temperature rises by 20 °C (68° F) or more after starting the engine.
• Engine coolant temperature reaches 70 °C (158° F) or more.
• The ignition switch is turned from ON to OFF.
NOTE:
• When the same malfunction is detected regardless of driving conditions, reset the counter of driving pattern A.
• When the above conditions are satisfied without detecting t he same malfunction, reset the counter of driving
pattern A.
DRIVING PATTERN B
Driving pattern B means a trip satisfying the following conditions.
• Engine speed reaches 400 rpm or more.
• Engine coolant temperature reaches 70 °C (158° F) or more.
• Vehicle speed of 70 – 120 km/h (44 – 75 MPH) is maintained for 60 seconds or more under the control of closed loop.
• Vehicle speed of 30 – 60 km/h (19 – 37 MPH) is maintained for 10 seconds or more under the control of closed loop.
• Under the closed loop control condition, the following st ate reaches 12 seconds or more in total: Vehicle
speed of 4 km/h (2 MPH) or less with idling condition.
• The state of driving at 10 km/h (7 MPH) or more reaches 10 minutes or more in total.
• A lapse of 22 minutes or more after engine start.
NOTE:
• Drive the vehicle at a constant velocity.
• When the same malfunction is detected regardless of driving conditions, reset the counter of driving pattern
B.
• When the above conditions are satisfied without detecting t he same malfunction, reset the counter of driving
pattern B.
DRIVING PATTERN C
Driving pattern C means operating vehicle as per the following:
The following conditions should be satisfied at the same time:
Engine speed: (Engine speed in the freeze frame data) ±375 rpm
*1: When the same malfunction is de-
tected in two consecutive trips, MIL
will light up. *2: MIL will turn OFF after vehicle is driv-
en 3 times (pattern B) without any
malfunctions. *3: When the same malfunction is de-
tected in two consecutive trips, the
DTC and the freeze frame data will be
stored in ECM.
*4: The DTC and the freeze frame data will not be displayed any longer after
vehicle is driven 40 times (pattern A)
without the same malfunction.
(The DTC and the freeze frame data
still remain in ECM.) *5: When a malfunction is detected for
the first time, the 1st trip DTC and the
1st trip freeze frame data will be
stored in ECM. *6: 1st trip DTC will be cleared after vehi-
cle is driven once (pattern B) without
the same malfunction.
*7: When the same malfunction is de- tected in the 2nd trip, the 1st trip
freeze frame data will be cleared.
Revision: May 2010 2011 Versa

DIAGNOSIS SYSTEM (ECM)EC-103
< FUNCTION DIAGNOSIS > [HR16DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
PERMANENT DTC SET TIMING
The setting timing of permanent DTC is stored in ECM
with the lighting of MIL when a DTC is confirmed.
DIAGNOSIS DESCRIPTION : Malfunction Indicator Lamp (MIL)INFOID:0000000006314669
DESCRIPTION
The MIL is located on the instrument panel.
1. The MIL will light up when the ignition switch is turned ON with-
out the engine running. This is a bulb check.
If the MIL does not light up, refer to EC-449, "
Component Func-
tion Check".
2. When the engine is start ed, the MIL should go off.
If the MIL remains on, the on board diagnostic system has
detected an engine system malfunction.
On Board Diagnosis FunctionINFOID:0000000006314670
ON BOARD DIAGNOSIS ITEM
The on board diagnostic system has the following functions.
BULB CHECK MODE
Description
This function allows damage inspection in the MIL bulb (blown, open circuit, etc.).
Operation Procedure
1. Turn ignition switch ON.
2. The MIL on the instrument panel should stay ON.
If it remains OFF, check MIL circuit. Refer to EC-451, "
Diagnosis Procedure".
SRT STATUS MODE
Description
This function allows to read if ECM has completed the self-diagnoses of major emission control systems and
components. For SRT, refer to EC-101, "
DIAGNOSIS DESCRIPTION : System Readiness Test (SRT) Code".
Operation Procedure
1. Turn ignition switch ON and wait 20 seconds.
2. SRT status is indicated as shown blow.
• ECM continues to illuminate MIL if all SRT codes are set.
SEF217U
Diagnostic test mode Function
Bulb check MIL can be checked.
SRT status ECM can read if SRT codes are set.
Malfunction warning If ECM detects a malfunction, it illuminates or blinks MIL to inform the driver that a malfunction has
been detected.
Self-diagnostic results DTCs or 1st trip DTCs stored in ECM can be read.
Accelerator pedal released po-
sition learning ECM can learn the accelerator pedal released position. Refer to EC-25, "
ACCELERATOR PEDAL
RELEASED POSITION LEARNING : Description".
Throttle valve closed position
learning ECM can learn the throttle valve closed position. Refer to
EC-25, "
THROTTLE VALVE CLOSED PO-
SITION LEARNING : Description".
Idle air volume learning ECM can learn the idle air volume. Refer to EC-25, "
IDLE AIR VOLUME LEARNING : Description".
Mixture ratio self-learning value
clear Mixture ratio self-learning value can be erased. Refer to
EC-27, "
MIXTURE RATIO SELF-LEARNING
VALUE CLEAR : Description".
Revision: May 2010 2011 Versa

DIAGNOSIS SYSTEM (ECM)EC-109
< FUNCTION DIAGNOSIS > [HR16DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
OA/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.
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) 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
swi t
ch

are OFF.
Monitored item Unit
DescriptionRemarks
Revision: May 2010 2011 Versa

DIAGNOSIS SYSTEM (ECM)EC-111
< FUNCTION DIAGNOSIS > [HR16DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
NOTE:
Any monitored item that does not match the vehicle
being diagnosed is deleted from the display automatically.
ACTIVE TEST MODE
Test Item
A/F S1 HTR(B1) %• Air fuel ratio (A/F) sensor 1 heater control value com-
puted by ECM according to the input signals.
• The current flow to the heater becomes larger as the value increases.
AC PRESS SEN V • The signal voltage from the refrigerant pressure sen-
sor is displayed.
A/F ADJ-B1 —• Indicates the correction of factor stored in ECM. The
factor is calculated from the difference between the
target air-fuel ratio stored in ECM and the air-fuel ratio
calculated from A/F sensor 1 signal.
HO2 S2 DIAG2(B1) INCMP/
CMPLT NOTE:
The item is indicated, but not used.
A/F SEN1
DIAG2(B1) INCMP/
CMPLT NOTE:
The item is indicated, but not used.
Monitored item Unit
DescriptionRemarks
TEST ITEMCONDITION JUDGMENTCHECK ITEM (REMEDY)
FUEL INJECTION • Engine: Return to the original
trouble condition
• Change the amount of fuel injec-
tion using CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
• Harness and connectors
• Fuel injector
• Air fuel ratio (A/F) sensor 1
IGNITION TIMING • Engine: Return to the original
trouble condition
• Timing light: Set
• Retard the ignition timing using
CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
• Perform Idle Air Volume Learning.
POWER BALANCE • Engine: After warming up, idle
the engine.
• A/C switch OFF
• Selector lever: P or N position (A/ T), Neutral position (M/T)
• Cut off each fuel injector signal one at a time using CONSULT-
III. Engine runs rough or dies.
• Harness and connectors
• Compression
• Fuel injector
• Power transistor
• Spark plug
• Ignition coil
COOLING FAN* • Ignition switch: ON
• Turn the cooling fan “LOW”, “HI”
and “OFF” using CONSULT-III. Cooling fan moves and stops.
• Harness and connectors
• IPDM E/R (Cooling fan relay)
• Cooling fan motor
ENG COOLANT
TEMP • Engine: Return to the original
trouble condition
• Change the engine coolant tem-
perature using CONSULT-III. If trouble symptom disappears, see
CHECK ITEM. • Harness and connectors
• Engine coolant temperature sen-
sor
• Fuel injector
FUEL PUMP RELAY • Ignition switch: ON (Engine
stopped)
• Turn the fuel pump relay “ON”
and “OFF” using CONSULT-III
and listen to operating sound. Fuel pump relay makes the operat-
ing sound.
• Harness and connectors
•Fuel pump relay
PURG VOL CONT/V • Engine: After warming up, run
engine at 1,500 rpm.
• Change the EVAP canister purge volume control solenoid
valve opening percent using
CONSULT-III. Engine speed changes according
to the opening percent.
• Harness and connectors
• Solenoid valve
FUEL/T TEMP SEN • Change the fuel tank temperature using CONSULT-III.
Revision: May 2010 2011 Versa

EC-114
< COMPONENT DIAGNOSIS >[HR16DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
COMPONENT DIAGNOSIS
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
DescriptionINFOID:0000000005929795
The specification (SP) value indicates the tolerance of
the value that is displayed in “SPEC” of “DATA MONI-
TOR” mode of CONSULT-III during normal operation of the Engine Control System. When the value in “SPEC”
of “DATA MONITOR” mode is within the SP value, the Engine Control System is confirmed OK. When the
value in “SPEC” of “DATA MONITOR” mode is NOT withi n the SP value, the Engine Control System may have
one or more malfunctions.
The SP value is used to detect malfunctions that may af fect the Engine Control System, but will not light the
MIL.
The SP value will be displayed for the following three items:
• B/FUEL SCHDL (The fuel injection pulse width progr ammed into ECM prior to any learned on board correc-
tion)
• A/F ALPHA-B1 (The mean value of air-fuel ratio feedback correction factor per cycle)
• MAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Component Function CheckINFOID:0000000005929796
1.START
Make sure that all of the following conditions are satisfied.
• Vehicle driven distance: More than 5,000 km (3,107 miles)
• Barometric pressure: 98.3 - 104.3 kPa (1.003 - 1.064 kg/cm
2, 14.25 - 15.12 psi)
• Atmospheric temperature: 20 - 30 °C (68 - 86° F)
• Engine coolant temperature: 75 - 95 °C (167 - 203° F)
• Transmission: Warmed-up
- A/T models: After the engine is warmed up to norma l operating temperature, drive vehicle until “FLUID
TEMP SE” (A/T fluid te mperature sensor signal) indicates more than 60 °C (140 °F).
- M/T models: After the engine is warmed up to normal operating temperature, drive vehicle for 5 minutes.
• Electrical load: Not applied
- Rear window defogger switch, air conditioner switch, lighting switch are OFF. Steering wheel is straight
ahead.
• Engine speed: Idle
>> GO TO 2.
2.PERFORM “SPEC” OF “DATA MONITOR” MODE
With CONSULT-III
NOTE:
Perform “SPEC” in “DATA MONITOR” mode in maximum scale display.
1. Perform EC-20, "
BASIC INSPECTION : Special Repair Requirement".
2. Select “B/FUEL SCHDL”, “A/F ALPHA-B1” and “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode
with CONSULT-III.
3. Make sure that monitor items are within the SP value.
Is the inspection result normal?
YES >> END
NO >> Go to EC-115, "
Diagnosis Procedure".
Revision: May 2010 2011 Versa

EC-150
< COMPONENT DIAGNOSIS >[HR16DE]
P0101 MAF SENSOR
P0101 MAF SENSOR
DescriptionINFOID:0000000005929833
The mass air flow sensor (1) is placed in the stream of intake air. It
measures the intake flow rate by measuring a part of the entire
intake flow. The mass air flow sensor controls the temperature of the
hot wire to a certain amount. The heat generated by the hot wire is
reduced as the intake air flows around it. The more air, the greater
the heat loss.
Therefore, the electric current
supplied to hot wire is changed to
maintain the temperature of the hot wire as air flow increases. The
ECM detects the air flow by means of this current change.
DTC LogicINFOID:0000000005929834
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
If engine will not start or stops soon, wait at leas t 10 seconds with engine stopped (Ignition switch ON) instead
of running engine at idle speed.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A
1. Start engine and warm it up to normal operating temperature.
2. Run engine for at least 10 seconds at idle speed.
3. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-153, "Diagnosis Procedure".
NO-1 >> With CONSULT-III: GO TO 3.
NO-2 >> Without CONSULT-III: GO TO 5.
3.CHECK MASS AIR FL OW SENSOR FUNCTION
1. Turn ignition switch ON.
2. Start engine and warm it up to normal operating temperature. If engine cannot be started, go to EC-153, "
Diagnosis Procedure".
PBIA9559J
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0101 Mass air flow sensor cir-
cuit range/performance A)
A high voltage from the sensor is sent to
ECM under light load driving condition. • Harness or connectors
(The sensor circuit is open or shorted.)
• Mass air flow sensor
• EVAP control system pressure sensor
B) A low voltage from the sensor is sent to
ECM under heavy load driving condition. • Harness or connectors
(The sensor circuit is open or shorted.)
• Intake air leaks
• Mass air flow sensor
• EVAP control system pressure sensor
• Intake air temperature sensor
Revision: May 2010 2011 Versa

EC-232
< COMPONENT DIAGNOSIS >[HR16DE]
P0171 FUEL INJECTION SYSTEM FUNCTION
P0171 FUEL INJECTIO
N SYSTEM FUNCTION
DTC LogicINFOID:0000000005929910
DTC DETECTION LOGIC
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio f eedback signal from the A/F sensors 1. The ECM calcu-
lates the necessary compensation to correct the of fset between the actual and the theoretical ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
1. Clear the mixture ratio self-learning value. Refer to EC-27, "
MIXTURE RATIO SELF-LEARNING VALUE
CLEAR : Special Repair Requirement".
2. Start engine.
Is it difficult to start engine?
YES >> GO TO 3.
NO >> GO TO 4.
3.RESTART ENGINE
If it is difficult to start engine, the f uel injection system has a malfunction, too.
Crank engine while depressing accelerator pedal.
NOTE:
When depressing accelerator pedal three-fourths (3/4) or more, the control system does not start the
engine. Do not depress accelerator pedal too much.
Does engine start?
YES >> Go to EC-234, "Diagnosis Procedure".
NO >> Check exhaust and intake air leak visually.
4.PERFORM DTC CONFIRMATION PROCEDURE-II
1. Start engine and let it idle for at least 5 minutes.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-234, "Diagnosis Procedure".
NO >> GO TO 5.
Sensor Input signal to ECM ECM functionActuator
A/F sensor 1 Density of oxygen in exhaust gas
(Mixture ratio feedback signal) Fuel injection control Fuel injector
DTC No. Trouble diagnosis name
DTC detecting conditionPossible cause
P0171 Fuel injection system too
lean • Fuel injection system does not operate properly.
• The amount of mixture ratio compensation is too
large. (The mixture ratio is too lean.) • Intake air leaks
• A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Mass air flow sensor
• Incorrect PCV hose connection
Revision: May 2010
2011 Versa

EC-238
< COMPONENT DIAGNOSIS >[HR16DE]
P0172 FUEL INJECTION SYSTEM FUNCTION
P0172 FUEL INJECTIO
N SYSTEM FUNCTION
DTC LogicINFOID:0000000005929913
DTC DETECTION LOGIC
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio f eedback signal from the A/F sensors 1. The ECM calcu-
lates the necessary compensation to correct the of fset between the actual and the theoretical ratios.
In case the amount of the compensation value is extrem ely large (The actual mixture ratio is too rich.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
1. Clear the mixture ratio self-learning value. Refer to EC-27, "
MIXTURE RATIO SELF-LEARNING VALUE
CLEAR : Special Repair Requirement".
2. Start engine.
Is it difficult to start engine?
YES >> GO TO 3.
NO >> GO TO 4.
3.RESTART ENGINE
If it is difficult to start engine, the f uel injection system has a malfunction, too.
Crank engine while depressing accelerator pedal.
NOTE:
When depressing accelerator pedal three-fourths (3/4) or more, the control system does not start the
engine. Do not depress accelerator pedal too much.
Does engine start?
YES >> Go to EC-240, "Diagnosis Procedure".
NO >> Check exhaust and intake air leak visually.
4.PERFORM DTC CONFIRMATION PROCEDURE-II
1. Start engine and let it idle for at least 5 minutes.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-240, "Diagnosis Procedure".
NO >> GO TO 5.
5.PERFORM DTC CONFIRMATION PROCEDURE-III
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Start engine.
Sensor Input signal to ECM ECM functionActuator
A/F sensor 1 Density of oxygen in exhaust gas
(Mixture ratio
feedback signal) Fuel injection control Fuel injector
DTC No. Trouble diagnosis name
DTC detecting condition Possible cause
P0172 Fuel injection system too
rich • Fuel injection system does not operate properly.
• The amount of mixture ratio compensation is too
large. (The mixture ratio is too rich.) • A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Mass air flow sensor
Revision: May 2010
2011 Versa