Page 857 of 2267
The emission-related diagnostic information can be erased by selecting ªERASEº in the ªSELF-DIAG
RESULTSº mode with CONSULT-II.
How to Erase DTC (With GST)NCEC0031S0602NOTE:
If the diagnostic trouble code is not for CVT related items (see EC-SR-6), skip step 2.
1. If the ignition switch stays ªONº after repair work, be sure to turn ignition switch ªOFFº once. Wait at least
9 seconds and then turn it ªONº (engine stopped) again.
2. Perform ªSELF-DIAGNOSTIC PROCEDURE (Without CONSULT-II)º in AT section titled ªTROUBLE
DIAGNOSISº, ªSelf-diagnosisº. (The engine warm-up step can be skipped when performing the diagnosis
only to erase the DTC.)
3. Select Mode 4 with GST (Generic Scan Tool).
The emission-related diagnostic information can be erased by selecting Mode 4 with GST (Generic Scan Tool).
SEF950W
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONSR20DE
Emission-related Diagnostic Information (Cont'd)
EC-57
Page 858 of 2267

How to Erase DTC (No Tools)NCEC0031S0603NOTE:
If the diagnostic trouble code is not for CVT related items (see EC-SR-6), skip step 2.
1. If the ignition switch stays ªONº after repair work, be sure to turn ignition switch ªOFFº once. Wait at least
9 seconds and then turn it ªONº again.
2. Perform ªSELF-DIAGNOSTIC PROCEDURE (Without CONSULT-II)º in AT section titled ªTROUBLE
DIAGNOSISº, ªSelf-diagnosisº. (The engine warm-up step can be skipped when performing the diagnosis
only to erase the DTC.)
3. Change the diagnostic test mode from Mode II to Mode I by using the data link connector. (See EC-SR-
61.)
The emission-related diagnostic information can be erased by changing the diagnostic test mode from Diag-
nostic Test Mode II to Mode I by using the data link connector. (Refer to EC-SR-61.)
NOTE:
IIf the battery is disconnected, the emission-related diagnostic information will be lost after approx.
24 hours.
IErasing the emission-related diagnostic information using CONSULT-II or GST is easier and
quicker than switching the mode using the data link connector.
IThe following data are cleared when the ECM memory is erased.
1) Diagnostic trouble codes
2) 1st trip diagnostic trouble codes
3) Freeze frame data
4) 1st trip freeze frame data
5) System readiness test (SRT) codes
6) Test values
7) Distance traveled while MI is activated
8) Others
Actual work procedures are explained using a DTC as an example. Be careful so that not only the DTC, but
all of the data listed above, are cleared from the ECM memory during work procedures.
Malfunction Indicator (MI)
NATS (NISSAN ANTI-THEFT SYSTEM)
IIf the security indicator lights up with the ignition switch in the ªONº position or ªNATS MALFUNC-
TIONº is displayed on ªSELF-DIAG RESULTSº screen, perform self-diagnostic results mode with
CONSULT-II using NATS program card. Refer to NATS (Nissan Anti-Theft System) in EL section.
IConfirm no self-diagnostic results of NATS is displayed before touching ªERASEº in ªSELF-DIAG
RESULTSº mode with CONSULT-II.
IWhen replacing ECM, initialization of NATS system and registration of all NATS ignition key IDs
must be carried out with CONSULT-II using NATS program card.
Therefore, be sure to receive all keys from vehicle owner. Regarding the procedure of NATS initil-
ialization and NATS ignition key ID registration, refer to CONSULT-II operation manual, NATS.
SEF543X
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONSR20DE
Emission-related Diagnostic Information (Cont'd)
EC-58
Page 859 of 2267

DESCRIPTIONNCEC0032
The MI is located on the instrument panel.
1. The MI will light up when the ignition switch is turned ON without the engine running. This is a bulb check.
IIf the MI does not light up, refer to EL section (ªWARNING LAMPSº) or see EC-SR-329.
2. When the engine is started, the MI should go off.
If the MI remains on, the on board diagnostic system has detected an engine system malfunction.
On Board Diagnostic System FunctionNCEC0032S01The on board diagnostic system has the following four functions.
Diagnostic Test Mode I
1. BULB CHECK:
This function checks the MI bulb for damage (blown, open circuit, etc.).
If the MI does not come on, check MI circuit and ECM test mode selector. (See the following page.)
2. MALFUNCTION WARNING:
This is a usual driving condition. When a malfunction is detected twice in two consecutive driving cycles
(two trip detection logic), the MI will light up to inform the driver that a malfunction has been detected.
The following malfunctions will light up or blink the MI in the 1st trip.
IªMisfire (Possible three way catalyst damage)º
IªClosed loop controlº
IFail-safe mode
Diagnostic Test Mode II
3. SELF-DIAGNOSTIC RESULTS:
This function allows DTCs and 1st trip DTCs to be read.
4. HEATED OXYGEN SENSOR 1 (FRONT) MONITOR:
This function allows the fuel mixture condition (lean or rich), monitored by heated oxygen sensor 1 (front),
to be read.
MI Flashing without DTC
NCEC0032S0101If the ECM is in Diagnostic Test Mode II, MI may flash when engine is running. In this case, check ECM test
mode following ªHOW TO SWITCH DIAGNOSTIC TEST MODESº.
How to switch the diagnostic test (function) modes, and details of the above functions are described later.
(Refer to EC-SR-61.)
Condition Diagnostic Test Mode I Diagnostic Test Mode II
Ignition switch in ªONº position
Engine stopped
BULB CHECK SELF-DIAGNOSTIC RESULTS
Engine running
MALFUNCTION WARNINGHEATED OXYGEN SENSOR 1
(FRONT) MONITOR
The following emission-related diagnostic information is cleared when the ECM memory is erased.
1) Diagnostic trouble codes
2) 1st trip diagnostic trouble codes
3) Freeze frame data
SAT652J
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONSR20DE
Malfunction Indicator (MI) (Cont'd)
EC-59
Page 860 of 2267
4) 1st trip freeze frame data
5) System readiness test (SRT) codes
6) Test values
7) Distance traveled while MI is activated
8) Others
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONSR20DE
Malfunction Indicator (MI) (Cont'd)
EC-60
Page 861 of 2267

How to Switch Diagnostic Test ModesNCEC0032S02
*1: EC-SR-329
*2: EC-SR-59*3: EC-SR-329 *4: EC-SR-93SEF951W Turn ignition switch
ªONº (Do not start
engine.)
Mode I - MALFUNCTION
INDICATOR LAMP CHECK. *2
MI should come on.Check MI circuit. *1
Repair harness or connector.
Start engine.Diagnostic Test Mode I
Ð MALFUNCTION WARNING
Data link
connector
Connect CHK and IGN terminals
with a suitable harness.
MI should come off.Check MI and DDL circuits. *3
Check ECM fail-safe. *4Repair harness or connectors.
Wait at least 2 seconds.
Data link
connector
Disconnect the suitable harness
between CHK and IGN terminals.
DIAGNOSTIC TEST MODE II
Ð SELF-DIAGNOSTIC RESULTS
(ERASING ECM MEMORY) Start engineDiagnostic Test Mode II
Ð HEATED OXYGEN SENSOR 1 (FRONT)
MONITOR
Data link
connector
Wait at least 2 seconds.
lSwitching the modes is not possible when the
engine is running.
lWhen ignition switch is turned off during
diagnosis, power to ECM will drop after
approx. 9 seconds.
The diagnosis will automatically return to
Diagnostic Test Mode I.
Data link
connectorIf the suitable harness is disconnected
at this time, the diagnostic trouble code
will be erased from the backup memory
in the ECM. NG
NGNG
OK
NG
OK
OK
OK
OK
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONSR20DE
Malfunction Indicator (MI) (Cont'd)
EC-61
Page 862 of 2267

Diagnostic Test Mode I Ð Bulb CheckNCEC0032S03In this mode, the MI on the instrument panel should stay ON. If it remains OFF, check the MI bulb. Refer to
EL section (ªWARNING LAMPSº) or see EC-SR-329.
Diagnostic Test Mode I Ð Malfunction WarningNCEC0032S04
MI Condition
ON When the malfunction is detected or the ECM's CPU is malfunctioning.
OFF No malfunction.
IThese DTC numbers are clarified in Diagnostic Test Mode II (SELF-DIAGNOSTIC RESULTS).
Diagnostic Test Mode II Ð Self-diagnostic ResultsNCEC0032S05In this mode, the DTC and 1st trip DTC are indicated by the number of blinks of the MI.
The DTC and 1st trip DTC are displayed at the same time. If the MI does not illuminate in diagnostic test mode
I (Malfunction warning), all displayed items are 1st trip DTCs. If only one code is displayed when the MI illu-
minates in diagnostic test mode II (SELF-DIAGNOSTIC RESULTS), it is a DTC; if two or more codes are
displayed, they may be either DTCs or 1st trip DTCs. DTC No. is same as that of 1st trip DTC. These uni-
dentified codes can be identified by using the CONSULT or GST. A DTC will be used as an example for how
to read a code.
A particular trouble code can be identified by the number of four-digit numeral flashes. The ªzeroº is indicated
by the number of ten flashes. The length of time the 1000th-digit numeral flashes on and off is 1.2 seconds
consisting of an ON (0.6-second)-OFF (0.6-second) cycle.
The 100th-digit numeral and lower digit numerals consist of a 0.3-second ON and 0.3-second OFF cycle.
A change from one digit numeral to another occurs at an interval of 1.0 second OFF. In other words, the lat-
ter numeral appears on the display 1.3 seconds after the former numeral has disappeared.
A change from one trouble code to another occurs at an interval of 1.8 second off.
In this way, all the detected malfunctions are classified by their DTC numbers. The DTC ª0000º refers to no
malfunction. (See TROUBLE DIAGNOSIS Ð INDEX, EC-SR-6.)
How to Erase Diagnostic Test Mode II (Self-diagnostic results)
NCEC0032S0501The DTC can be erased from the backup memory in the ECM when the diagnostic test mode is changed from
Diagnostic Test Mode II to Diagnostic Test Mode I. (Refer to ªHOW TO SWITCH DIAGNOSTIC TEST
MODESº.)
IIf the battery is disconnected, the DTC will be lost from the backup memory after approx. 24 hours.
IBe careful not to erase the stored memory before starting trouble diagnoses.
SEF952W
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONSR20DE
Malfunction Indicator (MI) (Cont'd)
EC-62
Page 863 of 2267

Diagnostic Test Mode II Ð Front Heated Oxygen Sensor MonitorNCEC0032S06In this mode, the MI displays the condition of the fuel mixture (lean or rich) which is monitored by the heated
oxygen sensor 1 (front).
MI Fuel mixture condition in the exhaust gas Air fuel ratio feedback control condition
ON Lean
Closed loop system
OFF Rich
*Remains ON or OFF Any condition Open loop system
*: Maintains conditions just before switching to open loop.
To check the heated oxygen sensor 1 (front) function, start engine in the Diagnostic Test Mode II and warm
it up until engine coolant temperature indicator points to the middle of the gauge.
Next run engine at about 2,000 rpm for about 2 minutes under no-load conditions. Then make sure that the
MI comes ON more than 5 times within 10 seconds with engine running at 2,000 rpm under no-load.
OBD System Operation ChartNCEC0033RELATIONSHIP BETWEEN MI, 1ST TRIP DTC, DTC, AND DETECTABLE ITEMSNCEC0033S01IWhen a malfunction is detected for the first time, the 1st trip DTC and the 1st trip freeze frame data are
stored in the ECM memory.
IWhen the same malfunction is detected in two consecutive trips, the DTC and the freeze frame data are
stored in the ECM memory, and the MI will come on. For details, refer to ªTwo Trip Detection Logicº on
EC-SR-48.
IThe MI will go off after the vehicle is driven 3 times with no malfunction. The drive is counted only when
the recorded driving pattern is met (as stored in the ECM). If another malfunction occurs while counting,
the counter will reset.
IThe DTC and the freeze frame data will be stored until the vehicle is driven 40 times (driving pattern A)
without the same malfunction recurring (except for Misfire and Fuel Injection System). For Misfire and Fuel
Injection System, the DTC and freeze frame data will be stored until the vehicle is driven 80 times (driv-
ing pattern C) without the same malfunction recurring. The ªTIMEº in ªSELF-DIAGNOSTIC RESULTSº
mode of CONSULT-II will count the number of times the vehicle is driven.
IThe 1st trip DTC is not displayed when the self-diagnosis results in ªOKº for the 2nd trip.
SUMMARY CHARTNCEC0033S02
Items Fuel Injection System Misfire Other
MI (goes off) 3 (pattern B) 3 (pattern B) 3 (pattern B)
DTC, Freeze Frame Data (no display) 80 (pattern C) 80 (pattern C) 40 (pattern A)
1st Trip DTC (clear) 1 (pattern C), *1 1 (pattern C), *1 1 (pattern B)
1st Trip Freeze Frame Data (clear) *1, *2 *1, *2 1 (pattern B)
For details about patterns ªBº and ªCº under ªFuel Injection Systemº and ªMisfireº, see EC-SR-65.
For details about patterns ªAº and ªBº under ªOtherº, see EC-SR-67.
*1: Clear timing is at the moment OK is detected.
*2: Clear timing is when the same malfunction is detected in the 2nd trip.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONSR20DE
Malfunction Indicator (MI) (Cont'd)
EC-63
Page 864 of 2267

RELATIONSHIP BETWEEN MI, DTC, 1ST TRIP DTC AND DRIVING PATTERNS FOR
ªMISFIREº , ªFUEL INJECTION SYSTEMº
NCEC0033S03
*1: When the same malfunction is
detected in two consecutive trips,
MI will light up.
*2: MI will go off after vehicle is driven
3 times (pattern B) without any
malfunctions.
*3: When the same malfunction is
detected in two consecutive trips,
the DTC and the freeze frame
data will be stored in ECM.
*4: The DTC and the freeze framedata 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 tripfreeze frame data will be cleared
at the moment OK is detected.
*7: When the same malfunction is
detected in the 2nd trip, the 1st
trip freeze frame data will be
cleared.
*8: 1st trip DTC will be cleared when
vehicle is driven once (pattern C)
without the same malfunction after
DTC is stored in ECM.
SEF392S
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONSR20DE
OBD System Operation Chart (Cont'd)
EC-64