
15 CHECK HEATED OXYGEN SENSOR 1 SIGNAL
With CONSULT-II
1. Replace heated oxygen sensor 1.
2. See ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode.
3. Maintain engine at 2,000 rpm under no-load (engine is warmed up to normal operating temperature.). Check that the
monitor fluctuates between ªLEANº and ªRICHº more than five times during 10 seconds.
1 cycle: RICH®LEAN®RICH
2 cycles: RICH®LEAN®RICH®LEAN®RICH
Without CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1.
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. Set voltmeter probe between ECM terminal 50 and ground.
6. Make sure that voltage fluctuates between 0 - 0.3V and 0.6 - 1.0V more than 5 times during 10 seconds at 2,000 rpm.
1 time: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V
2 times: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V®0.6 - 1.0V®0 - 0.3V
OK or NG
OK©GO TO 12.
NG©GO TO 16.
16 DETECT MALFUNCTIONING PART
1. Connect heated oxygen sensor 1 harness connector to heated oxygen sensor 1.
2. Check fuel pressure regulator. Refer to EC-3034.
3. Check mass air flow sensor and its circuit.
Refer to EC-3143, EC-3151.
4. Check injector and its circuit.
Refer to EC-3369.
Clean or replace if necessary.
5. Check engine coolant temperature sensor and its circuit. Refer to EC-3165.
6. Check ECM function by substituting another known-good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
©GO TO 12.
+If a vehicle contains a part which is operating outside of design specifications with no MI
illumination, the part shall not be replaced prior to emission testing unless it is determined that
the part has been tampered with or abused in such a way that the diagnostic system cannot rea-
sonably be expected to detect the resulting malfunction.
BASIC SERVICE PROCEDUREKA24DE (EURO OBD)
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment
EC-3048

IntroductionNEEC0029The ECM has an on board diagnostic system which detects malfunctions related to engine sensors or actua-
tors. The ECM also records various emission-related diagnostic information including:
Diagnostic Trouble Code (DTC) Mode 3 of ISO 15031-5
Freeze Frame data Mode 2 of ISO 15031-5
System Readiness Test (SRT) code Mode 1 of ISO 15031-5
1st Trip Diagnostic Trouble Code (1st Trip DTC) Mode 7 of ISO 15031-5
1st Trip Freeze Frame data
Test values and Test limits Mode 6 of ISO 15031-5
Calibration ID Mode 9 of ISO 15031-6
The above information can be checked using procedures listed in the table below.
X: Applicable Ð: Not applicable
DTC 1st trip DTCFreeze Frame
data1st trip Freeze
Frame dataSRT code Test value
CONSULT-IIXXXXXÐ
GST X X*1 X Ð X X
*1: 1st trip DTCs for self-diagnoses concerning SRT items cannot be shown on the GST display.
The malfunction indicator (MI) on the instrument panel lights up when the same malfunction is detected in two
consecutive trips (Two trip detection logic), or when the ECM enters fail-safe mode. (Refer to EC-3101.)
Two Trip Detection LogicNEEC0030When a malfunction is detected for the first time, 1st trip DTC and 1st trip Freeze Frame data are stored in
the ECM memory. The MI will not light up 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 MI lights up. The MI lights up at the same time when the DTC is stored. <2nd
trip> The ªtripº in the ªTwo Trip Detection Logicº means a driving mode in which self-diagnosis is performed
during vehicle operation. Specific on board diagnostic items will cause the ECM to light up or blink the MI,
and store DTC and Freeze Frame data, even in the 1st trip, as shown below.
X: Applicable Ð: Not applicable
ItemsMI DTC 1st trip DTC
1st trip 2nd trip
1st trip
displaying2nd trip
displaying1st trip
displaying2nd trip
displaying
Blinking Lighting up Blinking Lighting up
Misfire (Possible three way cata-
lyst damage) Ð DTC: P0300 -
P0304 is being detectedX ÐÐÐÐÐXÐ
Misfire (Possible three way cata-
lyst damage) Ð DTC: P0300 -
P0304 is being detectedÐÐ X ÐÐXÐÐ
Fail-safe items (Refer to
EC-3101.)Ð X Ð Ð X*1 Ð X*1 Ð
Except above Ð Ð Ð X Ð X X Ð
*1: Except ªECMº
Emission-related Diagnostic InformationNEEC0031DTC AND 1ST TRIP DTCNEEC0031S01The 1st trip DTC (whose number is the same as the DTC number) is displayed for the latest self-diagnostic
result obtained. If the ECM memory was cleared previously, and the 1st trip DTC did not reoccur, the 1st trip
DTC will not be displayed. If a malfunction is detected during the 1st trip, the 1st trip DTC is stored in the ECM
memory. The MI will not light up (two trip detection logic). If the same malfunction is not detected in the 2nd
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION
KA24DE (EURO OBD)
Introduction
EC-3049

trip (meeting the required driving pattern), the 1st trip DTC is cleared from the ECM memory. If the same mal-
function is detected in the 2nd trip, both the 1st trip DTC and DTC are stored in the ECM memory and the MI
lights up. In other words, the DTC is stored in the ECM memory and the MI lights up when the same malfunc-
tion occurs in two consecutive 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. For malfunctions that blink or
light up the MI during the 1st trip, the DTC and 1st trip DTC are stored in the ECM memory.
Procedures for clearing the DTC and the 1st trip DTC from the ECM memory are described in ªHOW TO
ERASE EMISSION-RELATED DIAGNOSTIC INFORMATIONº. Refer to EC-3060.
For malfunctions in which 1st trip DTCs are displayed, refer to EC-3058. These items are required by legal
regulations to continuously monitor the system/component. In addition, the items monitored non-continuously
are also displayed on CONSULT-II.
1st trip DTC is specified in Mode 7 of ISO 15031-5. 1st trip DTC detection occurs without lighting up the MI
and therefore does not warn the driver of a problem. However, 1st trip DTC detection will not prevent the
vehicle from being tested, for example during Inspection/Maintenance (I/M) tests.
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 ªWork Flowº procedure Step II, refer to page EC-3084. Then perform ªDTC Confirmation
Procedureº or ªOverall Function Checkº to try to duplicate the problem. If the malfunction is duplicated, the
item requires repair.
How to read DTC and 1st Trip DTCNEEC0031S0101DTC and 1st trip DTC can be read by the following methods.
With CONSULT-II
With GST
CONSULT-II or GST (Generic Scan Tool) Examples: P0340 etc.
These DTCs are prescribed by ISO 15031-5.
(CONSULT-II also displays the malfunctioning component or system.)
+1st trip DTC No. is the same as DTC No.
+Output of a DTC indicates a malfunction. However, GST does not indicate whether the malfunction
is still occurring or has occurred in the past and has returned to normal.
CONSULT-II can identify malfunction status as shown below. Therefore, using CONSULT-II (if avail-
able) is recommended.
A sample of CONSULT-II display for DTC is shown below. DTC or 1st trip DTC of a malfunction is displayed
in SELF-DIAGNOSTIC RESULTS mode of CONSULT-II. Time data indicates how many times the vehicle was
driven after the last detection of a DTC.
If the DTC is being detected currently, the time data will be ª0º.
If a 1st trip DTC is stored in the ECM, the time data will be ª[1t]º.
LEC028A
FREEZE FRAME DATA AND 1ST TRIP FREEZE FRAME DATANEEC0031S02The ECM records the driving conditions such as fuel system status, calculated load value, engine coolant
temperature, short term fuel trim, long term fuel trim, engine speed, vehicle speed, throttle valve opening, 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-II or
GST. The 1st trip freeze frame data can only be displayed on the CONSULT-II screen, not on the GST. For
details, see EC-3073.
Only one set of freeze frame data (either 1st trip freeze frame data or freeze frame data) can be stored in the
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION
KA24DE (EURO OBD)
Emission-related Diagnostic Information
EC-3050

+The time required for each diagnosis varies with road surface conditions, weather, altitude, individual driv-
ing habits, etc.
Zone A refers to the range where the time required, for the diagnosis under normal conditions*, is the
shortest.
Zone B refers to the range where the diagnosis can still be performed if the diagnosis is not completed
within zone A.
*: Normal conditions refer to the following:
þ Sea level
þ Flat road
þ Ambient air temperature: 20 - 30ÉC (68 - 86ÉF)
þ Diagnosis is performed as quickly as possible under normal conditions.
Under different conditions [For example: ambient air temperature other than 20 - 30ÉC (68 - 86ÉF)], diag-
nosis may also be performed.
Pattern 1:
+The engine is started at the engine coolant temperature of þ10 to 35ÉC (14 to 95ÉF)
(where the voltage between the ECM terminal 59 and ground is 3.0 - 4.3V).
+The engine must be operated at idle speed until the engine coolant temperature is greater than 70ÉC
(158ÉF) (where the voltage between the ECM terminal 59 and ground is lower than 1.4V).
Pattern 2:
+When steady-state driving is performed again even after it is interrupted, each diagnosis can be conducted.
In this case, the time required for diagnosis may be extended.
*1: Depress the accelerator pedal until vehicle speed is 90 km/h (56 MPH), then release the accelerator pedal
and keep it released for more than 10 seconds. Depress the accelerator pedal until vehicle speed is 90 km/h
(56 MPH) again.
*2: Checking the vehicle speed with CONSULT-II or GST is advised.
Suggested upshift speeds for M/T models
Shown below are suggested vehicle speeds for shifting into a higher gear. These suggestions relate to fuel
economy and vehicle performance. Actual upshift speeds will vary according to road conditions, the weather
and individual driving habits.
For normal acceleration in low altitude areas
[less than 1,219 m (4,000 ft)]:For quick acceleration in low altitude
areas and high altitude areas
[over 1,219 m (4,000 ft)]:
Gear changeACCEL shift point
km/h (MPH)CRUISE shift point
km/h (MPH)km/h (MPH)
1st to 2nd 24 (15) 24 (15) 24 (15)
2nd to 3rd 40 (25) 29 (18) 40 (25)
3rd to 4th 58 (36) 48 (30) 64 (40)
4th to 5th 64 (40) 63 (39) 72 (45)
Suggested Maximum Speed in Each Gear
Downshift to a lower gear if the engine is not running smoothly, or if you need to accelerate.
Do not exceed the maximum suggested speed (shown below) in any gear. For level road driving, use the
highest gear suggested for that speed. Always observe posted speed limits and drive according to the road
conditions to ensure safe operation. Do not over-rev the engine when shifting to a lower gear as it may cause
engine damage or loss of vehicle control.
Gearkm/h (MPH)
2WD (AUTO mode)
1st 50 (30)
2nd 95 (60)
TEST VALUE AND TEST LIMIT (GST ONLY Ð NOT APPLICABLE TO CONSULT-II)NEEC0031S04The following is the information specified in Mode 6 of ISO 15031-5.
The test value is a parameter used to determine whether a system/circuit diagnostic test is ªOKº or ªNGº while
being monitored by the ECM during self-diagnosis. The test limit is a reference value which is specified as the
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION
KA24DE (EURO OBD)
Emission-related Diagnostic Information
EC-3057

HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATIONNEEC0031S06How to Erase DTC (With CONSULT-II)NEEC0031S06011. If the ignition switch stays ON after repair work, be sure to turn ignition switch OFF once. Wait at least 5
seconds and then turn it ON (engine stopped) again.
2. Turn CONSULT-II ªONº and touch ªENGINEº.
3. Touch ªSELF-DIAG RESULTSº.
4. Touch ªERASEº. (The DTC in the ECM will be erased.)
SEC312D
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)NEEC0031S06021. If the ignition switch stays ON after repair work, be sure to turn ignition switch OFF once. Wait at least 5
seconds and then turn it ON (engine stopped) again.
2. Select Mode 4 with GST (Generic Scan Tool).
The emission-related diagnostic information in the ECM can be erased by selecting Mode 4 with GST (Generic
Scan Tool).
NOTE:
+If the battery is disconnected, the emission-related diagnostic information will be lost after approx.
24 hours.
+The 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) Others
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION
KA24DE (EURO OBD)
Emission-related Diagnostic Information
EC-3060

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.
NVIS (Nissan Vehicle Immobilizer System Ð
NATS)
NEEC1601
SEF515Y
+If 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 ªNVIS (Nissan Vehicle Immobilizer System Ð
NATS)º in EL section.
+Confirm no self-diagnostic results of NVIS (NATS) is displayed before touching ªERASEº in ªSELF-
DIAG RESULTSº mode with CONSULT-II.
+When replacing ECM, initialization of NVIS (NATS) system and registration of all NVIS (NATS) igni-
tion 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 procedures of NVIS (NATS)
initialization and NVIS (NATS) ignition key ID registration, refer to CONSULT-II operation manual,
IVIS/NVIS.
Malfunction Indicator (MI)
DESCRIPTIONNEEC0032
SAT652J
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.
+If the MI does not light up, refer to EL section, ªWARNING LAMPSº or see EC-3396.
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 FunctionNEEC0032S07The on board diagnostic system has the following four functions.
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION
KA24DE (EURO OBD)
Emission-related Diagnostic Information
EC-3061

Diagnostic Test
ModeKEY and ENG.
StatusFunction Explanation of Function
Mode I Ignition switch in
ªONº position
Engine stopped
BULB CHECK This function checks the MI bulb for damage (blown,
open circuit, etc.).
If the MI does not come on, check MI circuit.
Engine running
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 mal-
functions will light up or blink the MI in the 1st trip.
+ªMisfire (Possible three way catalyst damage)º
+ªClosed loop controlº
+Fail-safe mode
Mode II Ignition switch in
ªONº position
Engine stopped
SELF-DIAGNOSTIC RESULTS This function allows DTCs and 1st trip DTCs to be read.
Engine running
HEATED OXYGEN SENSOR 1
MONITORThis function allows the fuel mixture condition (lean or
rich), monitored by heated oxygen sensor 1, to be read.
MI Flashing without DTCNEEC0032S0701If the ECM is in Diagnostic Test Mode II, MI may flash when engine is running. In this case, check ECM diag-
nostic test mode. How to Switch Diagnostic Test Mode.
How to switch the diagnostic test (function) modes, and details of the above functions are described later. How
to Switch Diagnostic Test Mode.
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
4. 1st trip freeze frame data
5. System readiness test (SRT) codes
6. Test values
7. Others
How to Switch Diagnostic Test ModeNEEC0032S08NOTE:
+It is better to count the time accurately with a clock.
+It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit
has a malfunction.
+Always ECM returns to Diagnostic Test Mode I after ignition switch is turned ªOFFº.
How to Set Diagnostic Test Mode II (Self-diagnostic Results)
NEEC0032S08011. Confirm that accelerator pedal is fully released, turn ignition switch ªONº and wait 3 seconds.
2. Repeat the following procedure quickly five times within 5 seconds.
1) Fully depress the accelerator pedal.
2) Fully release the accelerator pedal.
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION
KA24DE (EURO OBD)
Malfunction Indicator (MI)
EC-3062

3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the MI starts
blinking.
4. Fully release the accelerator pedal.
ECM has entered to Diagnostic Test Mode II (Self-diagnostic results).
PBIB0092E
How to Set Diagnostic Test Mode II (Heated Oxygen Sensor 1 Monitor)NEEC0032S08021. Set the ECM in Diagnostic Test Mode II (Self-diagnostic results). Refer to How to Set Diagnostic Test Mode
II (Self-diagnostic Results).
2. Start Engine.
ECM has entered to Diagnostic Test Mode II (Heated oxygen sensor 1 monitor).
ECM will start heated oxygen sensor 1 monitoring from the bank 1 sensor.
How to Erase Diagnostic Test Mode II (Self-diagnostic Results)
NEEC0032S08041. Set ECM in Diagnostic Test Mode II (Self-diagnostic results). Refer to How to Set Diagnostic Test Mode
II (Self-diagnostic Results).
2. Fully depress the accelerator pedal and keep it for more than 10 seconds. The emission-related diagnos-
tic information has been erased from the backup memory in the ECM.
3. Fully release the accelerator pedal, and confirm the DTC 0000 is displayed.
Diagnostic Test Mode I Ð Bulb CheckNEEC0032S09In this mode, the MI on the instrument panel should stay ON. If it remains OFF, check the bulb. Refer to
WARNING LAMPS, EC-3396.
Diagnostic Test Mode I Ð Malfunction WarningNEEC0032S10
MI Condition
ON When the malfunction is detected or the ECM's CPU is malfunctioning.
OFF No malfunction.
+These DTC numbers are clarified in Diagnostic Test Mode II (SELF-DIAGNOSTIC RESULTS)
Diagnostic Test Mode II Ð Self-Diagnostic ResultsNEEC0032S11In this mode, the DTC and 1st trip DTC are indicated by the number of blinks of the MI as shown below.
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-II or GST. A DTC will be used as an example for how
to read a code.
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION
KA24DE (EURO OBD)
Malfunction Indicator (MI)
EC-3063