coolant temperature NISSAN TEANA 2003 Owner's Manual

EC-22
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ENGINE CONTROL SYSTEM

MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better reduce CO, HC and NOx emissions. This system uses
heated oxygen sensor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The
ECM adjusts the injection pulse width according to the sensor voltage signal. For more information about
heated oxygen sensor 1, refer to EC-143
. This maintains the mixture ratio within the range of stoichiometric
(ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the three way catalyst (manifold). Even if the switching
characteristics of heated oxygen sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal
from heated oxygen sensor 2.
Open Loop Control
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.

Deceleration and acceleration

High-load, high-speed operation

Malfunction of heated oxygen sensor 1 or its circuit

Insufficient activation of heated oxygen sensor 1 at low engine coolant temperature

High engine coolant temperature

During warm-up

After shifting from N to D

When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from heated oxygen
sensor 1. This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to
the theoretical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as orig-
inally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during operation (i.e., fuel injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is
then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from heated oxygen sensor 1 indicates whether the mixture ratio is RICH or LEAN compared
to the theoretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich, and an
increase in fuel volume if it is lean.
“Long term fuel trim” is overall fuel compensation carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
PBIB2953E

ENGINE CONTROL SYSTEM
EC-23
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FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycle according to the firing order. This system is used
when the engine is running.
Simultaneous Multiport Fuel Injection System
Fuel is injected simultaneously into all four cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The four fuel injectors will then receive the signals two times for each engine cycle.
This system is used when the engine is being started and/or if the fail-safe system (CPU) is operating.
FUEL SHUT-OFF
Fuel to each cylinder is cut off during deceleration or operation of the engine at excessively high speeds.
Electronic Ignition (EI) SystemBBS005BG
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
Firing order: 1-3-4-2
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the
engine. The ignition timing data is stored in the ECM.
The ECM receives information such as the injection pulse width and camshaft position sensor signal. Comput-
ing this information, ignition signals are transmitted to the power transistor.
During the following conditions, the ignition timing is revised by the ECM according to the other data stored in
the ECM.

At starting

During warm-up

At idle

At low battery voltage

During acceleration
SEF337W
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
2
Piston position
Ignition timing
controlPower transistor Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Knock sensor Engine knocking
Park/neutral position (PNP) switch Gear position
Battery
Battery voltage*
2
Wheel sensor
Vehicle speed*1

EC-24
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ENGINE CONTROL SYSTEM

The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
Fuel Cut Control (At No Load and High Engine Speed)BBS005BH
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
If the engine speed is above 1,800 rpm under no load (for example, the shift position is neutral and engine
speed is over 1,800 rpm) fuel will be cut off after some time. The exact time when the fuel is cut off varies
based on engine speed.
Fuel cut will be operated until the engine speed reaches 1,500 rpm, then fuel cut will be cancelled.
NOTE:
This function is different from deceleration control listed under Multiport Fuel Injection (MFI) System, EC-21
.
Sensor Input Signal to ECM ECM function Actuator
Park/neutral position (PNP) switch Neutral position
Fuel cut control Fuel injector Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed
Wheel sensor Vehicle speed*

AIR CONDITIONING CUT CONTROL
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AIR CONDITIONING CUT CONTROLPFP:23710
Input/Output Signal ChartBBS005BI
*1: This signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signal of engine speed and battery voltage.
SYSTEM DESCRIPTION
This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned OFF.

When the accelerator pedal is fully depressed.

When cranking the engine.

At high engine speeds.

When the engine coolant temperature becomes excessively high.

When operating power steering during low engine speed or low vehicle speed.

When engine speed is excessively low.

When refrigerant pressure is excessively low or high.
Sensor Input Signal to ECM ECM function Actuator
Air conditioner switch Air conditioner ON signal
Air conditioner
cut controlAir conditioner relay Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed*
2
Engine coolant temperature sensor Engine coolant temperature
Refrigerant pressure sensor Refrigerant pressure
Power steering pressure sensor Power steering operation
Wheel sensor
Vehicle speed*
1
Battery
Battery voltage*2

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-35
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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 EC-35, "
HOW
TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION" .
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-53, "
WORK FLOW" . Then perform DTC Confir-
mation Procedure or Overall Function Check to try to duplicate the malfunction. If the malfunction is dupli-
cated, the item requires repair.
How to Read DTC and 1st Trip DTC
DTC and 1st trip DTC can be read by the following methods.
With CONSULT-II
CONSULT-II displays the DTC in “SELF-DIAG RESULTS” mode. Examples: P0117, P0340, P1217, etc.
(CONSULT-II also displays the malfunctioning component or system.)
Without CONSULT-II
The number of blinks of the MI in the Diagnostic Test Mode II (Self-Diagnostic Results) indicates the DTC.
Example: 0117, 0340, 1217, etc.

1st trip DTC No. is the same as DTC No.

Output of a DTC indicates a malfunction. However, the Diagnostic Test Mode II do 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 and 1st trip DTC is shown below. DTC or 1st trip DTC of a malfunc-
tion 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 [0].
If a 1st trip DTC is stored in the ECM, the time data will be [1t].
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, 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.
Only one set of freeze frame data (either 1st trip freeze frame data or freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM memory along with the 1st trip DTC. There is no priority
for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once
freeze frame data (2nd trip detection/MI ON) is stored in the ECM memory, 1st trip freeze frame data is no
longer stored. Remember, only one set of freeze frame data can be stored in the ECM.
Both 1st trip freeze frame data and freeze frame data (along with the DTCs) are cleared when the ECM mem-
ory is erased. Procedures for clearing the ECM memory are described in EC-35, "
HOW TO ERASE EMIS-
SION-RELATED DIAGNOSTIC INFORMATION" .
HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION
How to Erase DTC
WITH CONSULT-II
The emission related diagnostic information in the ECM can be erased by selecting “ERASE” in the “SELF-
DIAG RESULTS” mode with CONSULT-II.
PBIB0911E

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-39
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played, they may be either DTCs or 1st trip DTCs. DTC No. is same as that of 1st trip DTC. These unidentified
codes can be identified by using the CONSULT-II. 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 “zero” is indicated
by the number of ten flashes. The length of time the 1,000th-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 later
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 0000 refers to no mal-
function. (See EC-10, "
INDEX FOR DTC" )
How to Erase Diagnostic Test Mode II (Self-Diagnostic Results)
The DTC can be erased from the back up memory in the ECM by depressing accelerator pedal. Refer to EC-
37, "HOW TO SWITCH DIAGNOSTIC TEST MODE" .

If the battery is disconnected, the DTC will be lost from the backup memory within 24 hours.

Be careful not to erase the stored memory before starting trouble diagnoses.
DIAGNOSTIC TEST MODE II — HEATED OXYGEN SENSOR 1 MONITOR
In this mode, the MI displays the condition of the fuel mixture (lean or rich) which is monitored by the heated
oxygen sensor 1.
*: Maintains conditions just before switching to open loop.
To check the heated oxygen sensor 1 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.
PBIA3905E
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

EC-40
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BASIC SERVICE PROCEDURE

BASIC SERVICE PROCEDUREPFP:00018
Basic InspectionBBS005BT
1. INSPECTION START
1. Check service records for any recent repairs that may indicate a related malfunction, or a current need for
scheduled maintenance.
2. Open engine hood and check the following:
–Harness connectors for improper connections
–Wiring harness for improper connections, pinches and cut
–Vacuum hoses for splits, kinks and improper connections
–Hoses and ducts for leaks
–Air cleaner clogging
–Gasket
3. Confirm that electrical or mechanical loads are not applied.
–Headlamp switch is OFF.
–Air conditioner switch is OFF.
–Rear window defogger switch is OFF.
–Steering wheel is in the straight-ahead position, etc.
4. Start engine and warm it up until engine coolant temperature
indicator points the middle of gauge.
Ensure engine stays below 1,000 rpm.
5. Run engine at about 2,000 rpm for about 2 minutes under no-
load.
6. Make sure that no DTC is displayed with CONSULT-II.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. REPAIR OR REPLACE
Repair or replace components as necessary according to corresponding Diagnostic Procedure.
>> GO TO 3
SEF983U
SEF976U
SEF977U

BASIC SERVICE PROCEDURE
EC-47
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3. Check ignition timing.
Procedure After Replacing ECMBBS005KR
When replacing ECM, the following procedure must be performed.
1. Perform initialization of NATS system and registration of all NATS ignition key IDs. Refer to BL-142, "
ECM
Re-Communicating Function" .
2. Perform EC-47, "
Accelerator Pedal Released Position Learning" .
3. Perform EC-47, "
Throttle Valve Closed Position Learning" .
4. Perform EC-47, "
Idle Air Volume Learning" .
Accelerator Pedal Released Position LearningBBS005BV
DESCRIPTION
Accelerator Pedal Released Position Learning is an operation to learn the fully released position of the accel-
erator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time
harness connector of accelerator pedal position sensor or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF and wait at least 10 seconds.
Throttle Valve Closed Position LearningBBS005BW
DESCRIPTION
Throttle Valve Closed Position Learning is an operation to learn the fully closed position of the throttle valve by
monitoring the throttle position sensor output signal. It must be performed each time harness connector of
electric throttle control actuator or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.
Idle Air Volume LearningBBS005BX
DESCRIPTION
Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specific
range. It must be performed under any of the following conditions:

Each time electric throttle control actuator or ECM is replaced.

Idle speed or ignition timing is out of specification.
PREPARATION
Before performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are missed for even a moment.

Battery voltage: More than 12.9V (At idle)

Engine coolant temperature: 70 - 95°C (158 - 203°F)
PBIB2177E

EC-58
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TROUBLE DIAGNOSIS

DTC Inspection Priority ChartBBS005C0
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:
If DTC U1000 and/or U1001 is displayed with other DTC, first perform the trouble diagnosis for DTC
U1000 and U1001. Refer to EC-113, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
Priority Detected items (DTC)
1

U1000 U1001 CAN communication line

P0102 P0103 Mass air flow sensor

P0117 P0118 Engine coolant temperature sensor

P0122 P0123 P0222 P0223 P1225 P1226 P2135 Throttle position sensor

P0327 P0328 Knock sensor

P0335 Crankshaft position sensor (POS)

P0340 Camshaft position sensor (PHASE)

P0500 Vehicle speed sensor

P0605 ECM

P1229 Sensor power supply

P1610-P1615 NATS

P1706 Park/Neutral position (PNP) switch

P2122 P2123 P2127 P2128 P2138 Accelerator pedal position sensor
2

P0132 P0134 Heated oxygen sensor 1

P0550 Power steering pressure sensor

P1065 ECM power supply

P1122 Electric throttle control function

P1124 P1126 Throttle control motor relay

P1128 Throttle control motor

P1720 Vehicle speed sensor

P1805 Brake switch
3

P0011 Intake valve timing control

P1121 Electric throttle control actuator

P1217 Engine over temperature (OVERHEAT)

EC-60
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TROUBLE DIAGNOSIS

Symptom Matrix ChartBBS005C2
SYSTEM — BASIC ENGINE CONTROL SYSTEM
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel pump circuit 11232 22 3 2EC-295
Fuel pressure regulator system334444444 4EC-49
Fuel injector circuit 11232 22 2EC-289
Evaporative emission system 334444444 4EC-27
Air Positive crankcase ventilation sys-
tem334444444 41EC-30
Incorrect idle speed adjustment 33 1111 1EC-40
Electric throttle control actuator 112332222 2 2EC-197
,
EC-200
,
EC-207
,
EC-213
IgnitionIncorrect ignition timing adjustment33111 11 1EC-40
Ignition circuit 11222 22 2EC-329
Main power supply and ground circuit 22333 33 23EC-106
Mass air flow sensor circuit 11222 22 2EC-124
Engine coolant temperature sensor circuit 11222322312EC-131
Throttle position sensor circuit 12 22222 2EC-136
,
EC-157
,
EC-229
,
EC-231
,
EC-265
Accelerator pedal position sensor circuit3212 2EC-233
,
EC-251
,
EC-258
,
EC-272
Heated oxygen sensor 1 circuit 1232 22 2EC-143
,
EC-150
,
EC-301
Knock sensor circuit 2 2 3EC-164
Crankshaft position sensor (POS) circuit 2 2EC-169
Camshaft position sensor (PHASE) circuit 2 2EC-176
Vehicle speed signal circuit 2 3 3 3EC-183
Power steering pressure sensor circuit 2 3333EC-185