Nissan Altima L32. Manual - part 251

ON BOARD DIAGNOSTIC (OBD) SYSTEM

EC-125

< FUNCTION DIAGNOSIS >

[QR25DE FOR CALIFORNIA]

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<Driving Pattern A>

• The A counter will be cleared when the malfunction is detected regardless of (1) - (4).

• The A counter will be counted up when (1) - (4) are satisfied without the same malfunction.

• The DTC will not be displayed after the A counter reaches 40.

<Driving Pattern B>

Driving 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 malfunctions.

• The MIL will go off when the B counter reaches 3 (*2 in OBD SYSTEM OPERATION CHART).

CONSULT-III Function

INFOID:0000000004349181

FUNCTION

*: The following emission-related diagnostic information is cleared when the ECM memory is erased.
• Diagnostic trouble codes
• 1st trip diagnostic trouble codes
• Freeze frame data
• 1st trip freeze frame data
• System readiness test (SRT) codes
• Test  values

ENGINE CONTROL COMPONENT PARTS/CONTROL SYSTEMS APPLICATION

AEC574

Diagnostic test mode

Function

Work support

This mode enables a technician to adjust some devices faster and more accurately by following the in-
dications on the CONSULT-III unit.

Self-diagnostic results

Self-diagnostic results such as 1st trip DTC, DTCs and 1st trip freeze frame data or freeze frame data 
can be read and erased quickly.*

Data monitor

Input/Output data in the ECM can be read.

Active test

Diagnostic Test Mode in which CONSULT-III drives some actuators apart from the ECMs and also shifts 
some parameters in a specified range.

DTC & SRT confirmation

The status of system monitoring tests and the self-diagnosis status/result can be confirmed.

Function test

This mode is used to inform customers when their vehicle condition requires periodic maintenance.

ECU part number

ECM part number can be read.

EC-126

< FUNCTION DIAGNOSIS >

[QR25DE FOR CALIFORNIA]

ON BOARD DIAGNOSTIC (OBD) SYSTEM

Item

DIAGNOSTIC TEST MODE

WORK 

SUPPORT

SELF-DIAGNOSTIC 

RESULTS

DATA 

MONI-

TOR

ACTIVE 

TEST

DTC & SRT

CONFIRMATION

DTC*1

FREEZE 

FRAME 
DATA*2

SRT STA-

TUS

DTC 

WORK 

SUP-

PORT

E

N

GINE

 CON

T

RO

L COMPONENT 

P

ARTS

INPUT

Crankshaft position sensor (POS)

×

×

×

Camshaft position sensor (PHASE)

×

×

×

Mass air flow sensor

×

×

Engine coolant temperature sensor

×

×

×

×

Air fuel ratio (A/F) sensor 1

×

×

×

×

Heated oxygen sensor 2

×

×

×

×

Heated oxygen sensor 3

×

×

×

Vehicle speed sensor

×

×

×

Accelerator pedal position sensor

×

×

Throttle position sensor

×

×

×

Fuel tank temperature sensor

×

×

×

EVAP control system pressure sensor

×

×

Intake air temperature sensor

×

×

×

Knock sensor

×

Refrigerant pressure sensor

×

Closed throttle position switch (accel-
erator pedal position sensor signal)

×

Air conditioner switch

×

Park/neutral position (PNP) switch

×

×

Stop lamp switch

×

×

Power steering pressure sensor

×

×

Battery voltage

×

Load signal

×

Primary speed sensor

×

×

Tumble control valve position sensor

×

×

Fuel level sensor

×

×

Battery current sensor

×

×

ASCD steering switch

×

×

ASCD brake switch

×

×

ON BOARD DIAGNOSTIC (OBD) SYSTEM

EC-127

< FUNCTION DIAGNOSIS >

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X: Applicable
*1: This item includes 1st trip DTCs.
*2: This mode includes 1st trip freeze frame data or freeze frame data. The items appear on CONSULT-III screen in freeze frame data
mode only if a 1st trip DTC or DTC is detected. For details, refer to 

EC-112, "Diagnosis Description"

.

*3: Always “CMPLT” is displayed.

INSPECTION PROCEDURE

Refer to CONSULT-III Operators Manual.

WORK SUPPORT MODE

Work Item

ENGINE COTNROL COMPONENT P

ARTS

OUTPUT

Fuel injector

×

×

Power transistor (Ignition timing)

×

×

Throttle control motor relay

×

×

Throttle control motor

×

EVAP canister purge volume control 
solenoid valve

×

×

×

×

Air conditioner relay

×

Fuel pump relay

×

×

×

Cooling fan relay

×

×

×

Air fuel ratio (A/F) sensor 1 heater

×

×

×*

3

Heated oxygen sensor 2 heater

×

×

×*

3

Heated oxygen sensor 3 heater

×

×

×*

3

EVAP canister vent control valve

×

×

×

×

Intake valve timing control solenoid 
valve

×

×

×

Alternator

×

×

Tumble control valve motor

×

×

×

Calculated load value

×

×

Item

DIAGNOSTIC TEST MODE

WORK 

SUPPORT

SELF-DIAGNOSTIC 

RESULTS

DATA 

MONI-

TOR

ACTIVE 

TEST

DTC & SRT

CONFIRMATION

DTC*1

FREEZE 

FRAME 
DATA*2

SRT STA-

TUS

DTC 

WORK 

SUP-

PORT

WORK ITEM

CONDITION

USAGE

FUEL PRESSURE RELEASE

• FUEL PUMP WILL STOP BY TOUCHING “START” DUR-

ING 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 COEF-
FICIENT.

When clearing mixture ratio self-
learning value

EC-128

< FUNCTION DIAGNOSIS >

[QR25DE FOR CALIFORNIA]

ON BOARD DIAGNOSTIC (OBD) SYSTEM

*: This function is not necessary in the usual service procedure.

SELF-DIAG RESULTS MODE

Self Diagnostic Item

Regarding items of DTC and 1st trip DTC, refer to 

EC-527, "DTC Index"

.)

Freeze Frame Data and 1st Trip Freeze Frame Data

EVAP SYSTEM CLOSE

CLOSE THE EVAP CANISTER VENT CONTROL VALVE IN 
ORDER TO MAKE EVAP SYSTEM CLOSE UNDER THE 
FOLLOWING CONDITIONS.
• IGN SW ON
• ENGINE NOT RUNNING
• AMBIENT TEMPERATURE IS ABOVE 0

°C (32°F).

• NO VACUUM AND NO HIGH PRESSURE IN EVAP SYS-

TEM

•  FUEL TANK TEMP. IS MORE THAN 0

°C (32°F).

• WITHIN 10 MINUTES AFTER STARTING “EVAP SYS-

TEM CLOSE”

• WHEN TRYING TO EXECUTE “EVAP SYSTEM CLOSE” 

UNDER THE CONDITION EXCEPT ABOVE, CONSULT-
II WILL DISCONTINUE IT AND DISPLAY APPROPRIATE 
INSTRUCTION.
NOTE:
WHEN STARTING ENGINE, CONSULT-III MAY DIS-
PLAY “BATTERY VOLTAGE IS LOW. CHARGE BAT-
TERY”, EVEN IN USING CHARGED BATTERY.

When detecting EVAP vapor leak 
point of EVAP system

VIN REGISTRATION

• IN THIS MODE, VIN IS REGISTERED IN ECM.

When registering VIN in ECM

TARGET IDLE RPM ADJ*

• IDLE CONDITION

When setting target idle speed

TARGET IGN TIM ADJ*

• IDLE CONDITION

When adjusting target ignition tim-
ing

WORK ITEM

CONDITION

USAGE

Freeze frame data 

item*

Description

DIAG TROUBLE 
CODE
[PXXXX]

• The engine control component part/control system has a trouble code, it is displayed as PXXXX. (Refer to 

EC-527, "DTC Index"

.)

FUEL SYS-B1

• “Fuel injection system status” at the moment a malfunction is detected is displayed.
• One mode in the following is displayed.

Mode2: Open loop due to detected system malfunction
Mode3: Open loop due to driving conditions (power enrichment, deceleration enleanment)
Mode4: Closed loop - using oxygen sensor(s) as feedback for fuel control
Mode5: 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 [

°C] 

or [

°F]

• The engine coolant temperature at the moment a malfunction is detected is displayed.

L-FUEL TRM-B1 [%]

• “Long-term fuel trim” 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.

S-FUEL TRM-B1 [%]

• “Short-term fuel trim” at the moment a malfunction is detected is displayed.
• The short-term fuel trim indicates dynamic or instantaneous feedback compensation to the base fuel sched-

ule.

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.