
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.
MODELS WITHOUT EURO-OBD SYSTEMNJEC0031S07DTC and 1st Trip DTCNJEC0031S0701The 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. If the same mal-
function 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 stored
in the ECM memory. In other words, the DTC is stored in the ECM memory when the same malfunction 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 fail-safe items, the DTC is stored in the
ECM memory even in the 1st trip.
Procedures for clearing the DTC and the 1st trip DTC from the ECM memory are described in ªHow to Erase
Emission-related Diagnostic Informationº, EC-73.
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 EC-98. Then perform ªDTC Confirmation Proce-
dureº 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 DTC
DTC and 1st trip DTC can be read by the following methods.
Without CONSULT-II
ECM displays the DTC by a set of four digit numbers with MI illumination in the diagnostic test mode II (Self-
diagnostic results). Example: 0100, 0115, 0340, 1335, etc.
With CONSULT-II
CONSULT-II displays the DTC in ªSELF-DIAG RESULTSº mode. Examples: P0100, P0115, P0340, P1335,
etc.
(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, ECM in the diagnostic test mode II (Self-diag-
nostic results) (If so equipped) 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, the use of CONSULT-II (if available) is recommended.
A sample CONSULT-II display for DTC and 1st trip DTC is shown below. DTC or 1st trip DTC of a malfunc-
tion is displayed in the 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.
SEF992X
Freeze Frame Data and 1st Trip Freeze Frame DataNJEC0031S0702The 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. For
details, see EC-86.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONQG
Emission-related Diagnostic Information (Cont'd)
EC-72

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 Chart (With Euro-OBD
Models Only)
NJEC0033RELATIONSHIP BETWEEN MI, 1ST TRIP DTC, DTC, AND DETECTABLE ITEMSNJEC0033S01+When 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.
+When 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-59.
+The 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.
+The 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.
+The 1st trip DTC is not displayed when the self-diagnosis results in ªOKº for the 2nd trip.
SUMMARY CHARTNJEC0033S02
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-80.
For details about patterns ªAº and ªBº under ªOtherº, see EC-82.
*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 DESCRIPTIONQG
Malfunction Indicator (MI) (Cont'd)
EC-78

EXPLANATION FOR DRIVING PATTERNS FOR ªMISFIRE
NJEC0033S04Driving Pattern BNJEC0033S0401Driving pattern B means the vehicle operation as follows:
All components and systems should be monitored at least once by the OBD system.
+The B counter will be cleared when the malfunction is detected once regardless of the driving pattern.
+The B counter will be counted up when driving pattern B is satisfied without any malfunction.
+The MI will go off when the B counter reaches 3. (*2 in EC-79)
Driving Pattern CNJEC0033S0402Driving pattern C means the vehicle operation as follows:
1) The following conditions should be satisfied at the same time:
Engine speed: (Engine speed in the freeze frame data)±375 rpm
Calculated load value: (Calculated load value in the freeze frame data)´(1±0.1) [%]
Engine coolant temperature (T) condition:
+When the freeze frame data shows lower than 70ÉC (158ÉF), ªTº should be lower than 70ÉC (158ÉF).
+When the freeze frame data shows higher than or equal to 70ÉC (158ÉF), ªTº should be higher than or
equal to 70ÉC (158ÉF).
Example:
If the stored freeze frame data is as follows:
Engine speed: 850 rpm, Calculated load value: 30%, Engine coolant temperature: 80ÉC (176ÉF)
To be satisfied with driving pattern C, the vehicle should run under the following conditions:
Engine speed: 475 - 1,225 rpm, Calculated load value: 27 - 33%, Engine coolant temperature: more than 70ÉC
(158ÉF)
+The C counter will be cleared when the malfunction is detected regardless of driving pattern C.
+The C counter will be counted up when driving pattern C is satisfied without the same malfunction.
+The DTC will not be displayed after C counter reaches 80.
+The 1st trip DTC will be cleared when C counter is counted once without the same malfunction after DTC
is stored in ECM.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONQG
OBD System Operation Chart (With Euro-OBD Models Only) (Cont'd)
EC-80

ENGINE CONTROL COMPONENT PARTS/CONTROL
SYSTEMS APPLICATION
NJEC0034S02
ItemDIAGNOSTIC TEST MODE
WORK
SUP-
PORTSELF-DIAGNOSTIC
RESULTS
D ATA
MONI-
TORD ATA
MONI-
TOR
(SPEC)ACTIVE
TESTDTC & SRT
CONFIRMATION
DTC*1FREEZE
FRAME
DATA*2SRT
STA-
TUSDTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUTCamshaft position sensor
(PHASE)XEngine
speed
XEngine
speed
XEngine
speed
X
Crankshaft position sensor
(POS)X*3
Mass air flow sensor X X X
Engine coolant temperature
sensorXXXXX
Heated oxygen sensor 1
(front)X X X X*3 X*3
Heated oxygen sensor 2
(rear)X*3 X X X*3 X*3
Vehicle speed sensorXXXX
Throttle position sensor X X X
Fuel tank temperature sensor X X
EGR temperature sensor*4 X*3 X X
Intake air temperature sensor X*3 X X X
Knock sensor X
Ignition switch (start signal) X X
Closed throttle position
switch*4X*3 X X
Closed throttle position switch
(throttle position sensor sig-
nal)XX
Air conditioner switch X X
Refrigerant pressure sensor X X
Park/Neutral position (PNP)
switchX*3 X X
Power steering oil pressure
switchXX
Electrical load X X
Heater fan switch X X
Battery voltage X X
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONQG
CONSULT-II (Cont'd)
EC-84

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
WORK SUPPORT MODENJEC0034S04
WORK ITEM CONDITION USAGE
TP SW/TP SEN IDLE POSI ADJ+FOLLOW THE BASIC INSPECTION INSTRUCTION IN
THE SERVICE MANUAL.When adjusting the idle throttle
position
FUEL PRESSURE RELEASE+FUEL PUMP WILL STOP BY TOUCHING ªSTARTº
DURING IDLING.
CRANK A FEW TIMES AFTER ENGINE STALLS.When releasing fuel pressure
from fuel line
IDLE AIR VOL LEARN+THE IDLE AIR VOLUME THAT KEEPS THE ENGINE
WITHIN THE SPECIFIED RANGE IS MEMORIZED IN
ECM.When learning the idle air volume
SELF-LEARNING CONT+THE COEFFICIENT OF SELF-LEARNING CONTROL
MIXTURE RATIO RETURNS TO THE ORIGINAL
COEFFICIENT.When clear the coefficient of self-
learnign control value
TARGET IDLE RPM ADJ*+IDLE CONDITION When setting target idle speed
TARGET IGNITION TIMING ADJ*+IDLE CONDITION When adjusting target ignition tim-
ing
After adjustment, confirm target
ignition timing with a timing light.
+If once the ªTARGET IDLE
RPM ADJº has been done, the
Idle Air Volume Learning proce-
dure will not be completed.
*: This function is not necessary in the usual service procedure.
SELF DIAGNOSTIC MODENJEC0034S05DTC and 1st Trip DTCNJEC0034S0501Regarding items of ªDTC and 1st trip DTCº, refer to
ªTROUBLE DIAGNOSIS Ð INDEXº, EC-10.
Freeze Frame Data and 1st Trip Freeze Frame DataNJEC0034S0502
Freeze frame data
item*Description
DIAG TROUBLE
CODE
[PXXXX]+Engine Control component part/control system has a trouble code, it is displayed as ªPXXXXº. (Refer to
ªAlphabetical & P No. Index for DTCº, EC-10.)
FUEL SYS-B1+ªFuel injection system statusº at the moment a malfunction is detected is displayed.
+One mode in the following is displayed.
ªMODE 2º: Open loop due to detected system malfunction
ªMODE 3º: Open loop due to driving conditions (power enrichment, deceleration enrichment)
ªMODE 4º: Closed loop - using oxygen sensor(s) as feedback for fuel control
ªMODE 5º: Open loop - has not yet satisfied condition to go to closed loop
CAL/LD VALUE [%]+The calculated load value at the moment a malfunction is detected is displayed.
COOLANT TEMP [ÉC]
or [ÉF]+The engine coolant temperature at the moment a malfunction is detected is displayed.
L-FUEL TRIM-B1 [%]+ªLong-term fuel trimº at the moment a malfunction is detected is displayed.
+The long-term fuel trim indicates much more gradual feedback compensation to the base fuel schedule
than short-term fuel trim.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONQG
CONSULT-II (Cont'd)
EC-86
![NISSAN ALMERA 2001 Service Manual Freeze frame data
item*Description
S-FUEL TRIM-B1 [%]+ªShort-term fuel trimº at the moment a malfunction is detected is displayed.
+The short-term fuel trim indicates dynamic or instantaneous feedba NISSAN ALMERA 2001 Service Manual Freeze frame data
item*Description
S-FUEL TRIM-B1 [%]+ªShort-term fuel trimº at the moment a malfunction is detected is displayed.
+The short-term fuel trim indicates dynamic or instantaneous feedba](/manual-img/5/57348/w960_57348-810.png)
Freeze frame data
item*Description
S-FUEL TRIM-B1 [%]+ªShort-term fuel trimº at the moment a malfunction is detected is displayed.
+The short-term fuel trim indicates dynamic or instantaneous feedback compensation to the base fuel
schedule.
ENGINE SPEED
[rpm]+The engine speed at the moment a malfunction is detected is displayed.
VEHICL SPEED
[km/h] or [mph]+The vehicle speed at the moment a malfunction is detected is displayed.
ABSOL TH´P/S [%]+The throttle valve opening angle at the moment a malfunction is detected is displayed.
B/FUEL SCHDL
[msec]+The base fuel schedule at the moment a malfunction is detected is displayed.
INT/A TEMP SE [ÉC]
or [ÉF]+The intake air temperature at the moment a malfunction is detected is displayed.
*: The items are the same as those of 1st trip freeze frame data.
DATA MONITOR MODENJEC0034S06
Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
ENG SPEED [rpm]jj+Indicates the engine speed computed from
the POS signal of the crankshaft position
sensor.+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]jj+The signal voltage of the mass air flow sen-
sor is displayed.+When the engine is stopped, a cer-
tain value is indicated.
B/FUEL SCHDL
[msec]+ªBase fuel scheduleº indicates the fuel
injection pulse width programmed into
ECM, prior to any learned on board correc-
tion.
A/F ALPHA-B1 [%]j+Indicates the mean value of the air-fuel
ratio feedback correction factor per cycle.+When the engine is stopped, a cer-
tain value is indicated.
+This data also includes the data for
the air-fuel ratio learning control.
COOLAN TEMP/S
[ÉC] or [ÉF]jj+The engine coolant temperature (deter-
mined by the signal voltage of the engine
coolant temperature sensor) is displayed.+When the engine coolant tempera-
ture sensor is open or short-
circuited, ECM enters fail-safe
mode. The engine coolant tempera-
ture determined by the ECM is dis-
played.
HO2S1 (B1) [V]jj+The signal voltage of the heated oxygen
sensor 1 (front) is displayed.
HO2S2 (B1) [V]j+The signal voltage of the heated oxygen
sensor 2 (rear) is displayed.
HO2S1 MNTR (B1)
[RICH/LEAN]j+Display of heated oxygen sensor 1 (front)
signal during air-fuel ratio feedback control:
RICH ... means the mixture became ªrichº,
and control is being affected toward a
leaner mixture.
LEAN ... means the mixture became ªleanº,
and control is being affected toward a rich
mixture.+After turning ON the ignition switch,
ªRICHº is displayed until air-fuel
mixture ratio feedback control
begins.
+When the air-fuel ratio feedback is
clamped, the value just before the
clamping is displayed continuously.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONQG
CONSULT-II (Cont'd)
EC-87

TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
IACV-AAC/V
OPENING+Engine: After warming up, idle
the engine.
+Change the IACV-AAC valve
opening steps using CONSULT-
II.Engine speed changes according
to the opening steps.+Harness and connector
+IACV-AAC valve
POWER BAL-
ANCE+Engine: After warming up, idle
the engine.
+Air conditioner switch ªOFFº
+Shift lever ªNº
+Cut off each injector signal one
at a time using CONSULT-II.Engine runs rough or dies.+Harness and connector
+Compression
+Injectors
+Power transistor
+Spark plugs
+Ignition coils
COOLING FAN+Ignition switch: ON
+Turn the cooling fan ªONº and
ªOFFº using CONSULT-II.Cooling fan moves and stops.+Harness and connector
+Cooling fan motor
ENG COOLANT
TEMP+Engine: Return to the original
trouble condition
+Change the engine coolant tem-
perature indication using CON-
SULT-II.If trouble symptom disappears, see
CHECK ITEM.+Harness and connector
+Engine coolant temperature sen-
sor
+Fuel injectors
FUEL PUMP
RELAY+Ignition switch: ON
(Engine stopped)
+Turn the fuel pump relay ªONº
and ªOFFº using CONSULT-II
and listen to operating sound.Fuel pump relay makes the operat-
ing sound.+Harness and connector
+Fuel pump relay
EGR VOL
CONT/V
(If so equipped)+Engine: After warming up, idle
the engine.
+Change the EGR volume control
valve opening step using CON-
SULT-II.Engine speed changes according
to the opening step.+Harness and connector
+EGR volume control valve
VALVE TIMING
SOL+Ignition switch: ON
+Turn intake valve timing control
solenoid valve ªONº and ªOFFº
using CONSULT-II and listen for
operating sound.Intake valve timing control solenoid
valve makes an operating sound.+Harness and connector
+Intake valve timing control sole-
noid valve
SWIRL CONT
S O L VA LV E
(If so equipped)+Ignition switch: ON
+Turn solenoid valve ªONº and
ªOFFº with CONSULT-II and lis-
ten for operating sound.Solenoid valve makes an operating
sound.+Harness and connector
+Solenoid valve
PURG VOL
CONT/V+Engine: After warming up, idle
the engine.
+Change the EVAP canister
purge volume control solenoid
valve opening percent using
CONSULT-II.Engine speed changes according
to the opening percent.+Harness and connector
+EVAP canister purge volume
control solenoid valve
DTC AND SRT CONFIRMATION MODENJEC0034S08This mode is not available for models without Euro-OBD system.
SRT STATUS ModeNJEC0034S0801For details, refer to ªSYSTEM READINESS TEST (SRT) CODEº,
EC-62.
SRT Work Support ModeNJEC0034S0803This mode enables a technician to drive a vehicle to set the SRT
while monitoring the SRT status.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONQG
CONSULT-II (Cont'd)
EC-91

DTC Inspection Priority ChartNJEC0039If some DTCs are displayed at the same time, perform inspections one by one based on the following prior-
ity chart.
Priority Detected items (DTC)
1+P0100 Mass air flow sensor
+P0110 Intake air temperature sensor
+P0115 Engine coolant temperature sensor
+P0120 Throttle position sensor
+P0180 Fuel tank temperature sensor*1
+P0325 Knock sensor
+P0340 Camshaft position sensor (PHASE) circuit
+P0403 EGR volume control valve*1
+P0500 Vehicle speed sensor
+P0605 ECM
+P0335 Crankshaft position sensor (POS)
+P1605 A/T diagnostic communication line
+P1706 Park/Neutral position switch
2+P0130 - P0134 Heated oxygen sensor 1 (front)
+P0135 Heated oxygen sensor 1 heater (front)
+P0137 - P0140 Heated oxygen sensor 2 (rear)
+P0141 Heated oxygen sensor 2 heater (rear)
+P0443 EVAP canister purge volume control solenoid valve
+P0510 Closed throttle position switch*1
+P0705 - P0725, P0740 - P1760 A/T related sensors, solenoid valves and switches
+P1217 Overheat (Cooling system)
+P1401 EGR temperature sensor*1
3+P0171, P0172 Fuel injection system function
+P0300 - P0304 Misfire
+P0400, P1402 EGR function*1
+P0420 Three way catalyst function
+P0505 IACV-AAC valve
+P0731 - P0734, P0744 A/T function
+P 1111Intake valve timing control
+P1131 Swirl control valve control solenoid*1
*1: If so equipped
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONQG
DTC Inspection Priority Chart
EC-153