ENGINE CONTROL SYSTEM EC-723
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Revision: 2005 July 2005 FX
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-935
. 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., 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.
PBIB0121E
ON BOARD DIAGNOSTIC (OBD) SYSTEM EC-749
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Revision: 2005 July 2005 FX
*1: 1st trip DTC No. is the same as DTC No.
*2: This number is prescribed by SAE J2012.
*3: In Diagnostic Test Mode II (Self-diagnostic results), this number is controlled by NISSAN.
*4: The trouble shooting for this DTC needs CONSULT-II.
*5: SRT code will not be set it the self-diagnostic result is NG.
*6: When the fail-safe operations for both self-diagnoses occur at the same time, the MIL illuminates.
*7: When engine is running, MIL may flash. For the details, refer to EC-761, "
MIL Flashing Without DTC" .
*8: When the ECM is in the mode of displaying SRT status, MIL may flash. For the details, refer to EC-754, "
How to Display SRT Status"
.
*9: Models with ICC. ACC COMMAND VALUE*
9P1568 1568 — — 1 —
EC-1261
ASCD BRAKE SW P1572 1572 — — 1 — EC-1262
(Models
with ICC) EC-1271
(Models
with ASCD)
ASCD VHL SPD SEN P1574 1574 — — 1 — EC-1279
(Models
with ICC) EC-1281
(Models
with ASCD)
NATS MALFUNCTION P1610 -
P1615 1610 - 1615 — — 2 —
EC-744
P-N POS SW/CIRCUIT P1706 1706 — — 2 ×EC-1283
TURBINE REV S/CIRC P1716 1716 — — 2 ×AT- 1 4 1
V/SP SEN(A/T OUT) P1720 1720 — — 2 — EC-1288
A/T INTERLOCK P1730 1730 — — 1×AT- 1 4 5
I/C SOLENOID/CIRC P1752 1752 — — 1 ×AT- 1 5 0
I/C SOLENOID FNCTN P1754 1754 — — 1 ×AT- 1 5 2
FR/B SOLENOID/CIRC P1757 1757 — — 1 ×AT- 1 5 4
FR/B SOLENOID FNCT P1759 1759 — — 1 ×AT- 1 5 6
D/C SOLENOID/CIRC P1762 1762 — — 1 ×AT- 1 5 8
D/C SOLENOID FNCTN P1764 1764 — — 1 ×AT- 1 6 0
HLR/C SOL/CIRC P1767 1767 — — 1 ×AT- 1 6 2
HLR/C SOL FNCTN P1769 1769 — — 1 ×AT- 1 6 4
LC/B SOLENOID/CIRC P1772 1772 — — 1 ×AT- 1 6 6
LC/B SOLENOID FNCT P1774 1774 — — 1 ×AT- 1 6 8
SHIFT SIG FNCTN P1780 1780 — — 2 — EC-1290
VIAS S/V CIRC P1800 1800 — — 2 —EC-1292
BRAKE SW/CIRCUIT P1805 1805 — — 2 —EC-1297
APP SEN 1/CIRC P2122 2122 — — 1×EC-1302
APP SEN 1/CIRC P2123 2123 — — 1 ×EC-1302
APP SEN 2/CIRC P2127 2127 — — 1 ×EC-1309
APP SEN 2/CIRC P2128 2128 — — 1 ×EC-1309
TP SENSOR P2135 2135 — — 1 ×EC-1316
APP SENSOR P2138 2138 — — 1 ×EC-1323
Items
(CONSULT-II screen terms) DTC*
1
SRT code
Test value/
Te s t l i m i t
(GST only) Trip MIL
Reference
page
CONSULT-II
GST*
2ECM*3
EC-798
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TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
2P0031P0032 P0051 P0052 Heated oxygen sensor 1 heater
P0037 P0038 P0057 P0058 Heated oxygen sensor 2 heater
P0132 P0133 P0134 P0152 P0153 P0154 P1143 P1144 P1163 P1164 Heated oxygen sensor 1
P0138 P0139 P0158 P0159 P1146 P1147 P1166 P1167 Heated oxygen sensor 2
P0441 EVAP control system purge flow monitoring
P0444 P0445 P1444 EVAP canister purge volume control solenoid valve
P0447 P1446 EVAP canister vent control valve
P0451 P0452 P0453 EVAP control system pressure sensor
P0550 Power steering pressure sensor
P0710 P0720 P0740 P0744 P0745 P1716 P1720 P1730 P1752 P1754 P1757 P1759 P1762 P1764 P1767 P1769
P1772 P1774 A/T related sensors, solenoid valves and switches
P1065 ECM power supply
P 1111 P 11 3 6 I n ta k e v a l v e t i m i n g c o n t r o l s o l e n o i d v a l v e
P1122 Electric throttle control function
P1124 P1126 P1128 Electric throttle control actuator
P1140 P1145 Intake valve timing control position sensor
P1217 Engine over temperature (OVERHEAT)
P1805 Brake switch
3
P0011 P0021 Intake valve timing control
P0171 P0172 P0174 P0175 Fuel injection system function
P0300 - P0308 Misfire
P0420 P0430 Three way catalyst function
P0442 P0456 EVAP control system (SMALL LEAK, VERY SMALL LEAK)
P0455 EVAP control system (GROSS LEAK)
P0506 P0507 Idle speed control system
P1121 Electric throttle control actuator
P1148 P1168 Closed loop control
P1211 TCS control unit
P1212 TCS communication line
P1564 ICC steering switch/ASCD steering switch
P1568 ICC command value
P1572 ICC brake switch/ASCD brake switch
P1574 ICC vehicle speed sensor/ASCD vehicle speed sensor
P1780 Shift change signal
P1800 VIAS control solenoid valve
Priority Detected items (DTC)
EC-822
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TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
CONSULT-II Function (ENGINE)ABS007I7
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
Te s t v a l u e s Diagnostic test mode Function
Work support This mode enables a technician to adjust some devices faster and more accurately by following the
indications on the CONSULT-II 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.
Data monitor (SPEC) Input/Output of the specification for Basic fuel schedule, AFM, A/F feedback control value and the
other data monitor items can be read.
CAN diagnostic support
monitor The results of transmit/receive diagnosis of CAN communication can be read.
Active test Diagnostic Test Mode in which CONSULT-II 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.
ECM part number ECM part number can be read.
EC-832
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TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
*: Leaving cooling fan OFF with CONSULT-II while engine is running may cause the engine to overheat.
DTC & SRT CONFIRMATION MODE
SRT STATUS Mode
For details, refer to EC-751, "SYSTEM READINESS TEST (SRT) CODE" .
SRT WORK SUPPORT Mode
This mode enables a technician to drive a vehicle to set the SRT while monitoring the SRT status.
POWER BAL-
ANCE
Engine: After warming up, idle
the engine.
A/C switch OFF
Shift lever: N
Cut off each injector signal one at
a time using CONSULT-II. Engine runs rough or dies.
Harness and connectors
Compression
Fuel injector
Power transistor
Spark plug
Ignition coil
COOLING FAN*
Ignition switch: ON
Turn the cooling fan “HI”, “MID”
and “OFF” using CONSULT-II. Cooling fan moves and stops.
Harness and connectors
Cooling fan motor
IPDM E/R
ENG COOLANT
TEMP
Engine: Return to the original
trouble condition
Change the engine coolant tem-
perature using CONSULT-II. If trouble symptom disappears, see
CHECK ITEM.
Harness and connectors
Engine coolant temperature sen-
sor
Fuel injector
FUEL PUMP
RELAY
Ignition switch: ON (Engine
stopped)
Turn the fuel pump relay ON and
OFF using CONSULT-II and lis-
ten to operating sound. Fuel pump relay makes the operat-
ing sound.Harness and connectors
Fuel pump relay
VIAS SOL VALVE
Ignition switch: ON
Turn solenoid valve ON and OFF
with CONSULT-II and listen to
operating sound. Solenoid valve makes an operating
sound.Harness and connectors
Solenoid valve
PURG VOL
CONT/V
Engine: After warming up, run
engine at 1,500 rpm.
Change the EVAP canister purge
volume control solenoid valve
opening percent using CON-
SULT-II. Engine speed changes according to
the opening percent.Harness and connectors
Solenoid valve
FUEL/T TEMP
SEN
Change the fuel tank temperature using CONSULT-II.
VENT CON-
TROL/V
Ignition switch: ON (Engine
stopped)
Turn solenoid valve ON and OFF
with the CONSULT-II and listen
to operating sound. Solenoid valve makes an operating
sound.Harness and connectors
Solenoid valve
V/T ASSIGN
ANGLE
Engine: Return to the original
trouble condition
Change intake valve timing using
CONSULT-II. If trouble symptom disappears, see
CHECK ITEM.
Harness and connectors
Intake valve timing control sole-
noid valve
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
EC-966
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DTC P0138, P0158 HO2S2
Revision: 2005 July 2005 FX
DTC P0138, P0158 HO2S2PFP:226A0
Component DescriptionABS007LM
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the heated oxygen sensor 1 are
shifted, the air-fuel ratio is controlled to stoichiometric, by the signal
from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
CONSULT-II Reference Value in Data Monitor ModeABS007LN
Specification data are reference values.
On Board Diagnosis LogicABS007LO
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the heated oxygen sensor 1. The oxygen
storage capacity of the three way catalyst (manifold) causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the voltage is unusually high during
the various driving condition such as fuel-cut.
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)
Engine: After warming up
After keeping engine speed
between 3,500 and 4,000 rpm for
1 minute and at idle for 1 minute
under no load Revving engine from idle up to 3,000 rpm
quickly. 0 - 0.3V
←→ Approx. 0.6 -
1.0V
HO2S2 MNTR (B1)
HO2S2 MNTR (B2) LEAN
←→ RICH
PBIB1848E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0138
0138
(Bank 1) Heated oxygen sensor
2 circuit high voltage An excessively high voltage from the sensor is
sent to ECM.
Harness or connectors
(The sensor circuit is open or shorted)
Heated oxygen sensor 2
P0158
0158
(Bank 2)
DTC P0139, P0159 HO2S2 EC-975
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Revision: 2005 July 2005 FX
DTC P0139, P0159 HO2S2PFP:226A0
Component DescriptionABS007LU
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the heated oxygen sensor 1 are
shifted, the air-fuel ratio is controlled to stoichiometric, by the signal
from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
CONSULT-II Reference Value in Data Monitor ModeABS007LV
Specification data are reference values.
On Board Diagnosis LogicABS007LW
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the heated oxygen sensor 1. The oxygen
storage capacity of the three way catalyst (manifold) causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the switching response of the sen-
sor's voltage is faster than specified during the various driving condi-
tion such as fuel-cut.
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)
Engine: After warming up
After keeping engine speed
between 3,500 and 4,000 rpm for
1 minute and at idle for 1 minute
under no load Revving engine from idle up to 3,000 rpm
quickly. 0 - 0.3V
←→ Approx. 0.6 -
1.0V
HO2S2 MNTR (B1)
HO2S2 MNTR (B2) LEAN
←→ RICH
SEF302U
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0139
0139
(Bank 1) Heated oxygen sensor
2 circuit slow response It takes more time for the sensor to respond
between rich and lean than the specified time.
Harness or connectors
(The sensor circuit is open or shorted)
Heated oxygen sensor 2
Fuel pressure
Fuel injector
Intake air leaks
P0159
0159
(Bank 2)
EC-1148
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DTC P1121 ELECTRIC THROTTLE CONTROL ACTUATOR
Revision: 2005 July 2005 FX
DTC P1121 ELECTRIC THROTTLE CONTROL ACTUATORPFP:16119
Component DescriptionABS007QS
Electric throttle control actuator consists of throttle control motor, throttle position sensor, etc.
The throttle control motor is operated by the ECM and it opens and closes the throttle valve.
The throttle position sensor detects the throttle valve position, and the opening and closing speed of the throt-
tle valve and feeds the voltage signals to the ECM. The ECM judges the current opening angle of the throttle
valve from these signals and the ECM controls the throttle control motor to make the throttle valve opening
angle properly in response to driving condition.
On Board Diagnosis LogicABS007QT
This self-diagnosis has one trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureABS007QU
NOTE:
Perform PROCEDURE FOR MALFUNCTION A AND B first. If the DTC cannot be confirmed, perform
PROCEDURE FOR MALFUNCTION C.
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait
at least 10 seconds before conducting the next test.
PROCEDURE FOR MALFUNCTION A AND B
With CONSULT-II
1. Turn ignition switch ON and wait at least 1 second.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Shift selector lever to D position and wait at least 3 seconds.
4. Shift selector lever to P position.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Turn ignition switch ON and wait at least 1 second.
7. Shift selector lever to D position and wait at least 3 seconds.
8. Shift selector lever to P position.
9. Turn ignition switch OFF, wait at least 10 seconds, and then turn ON.
10. If DTC is detected, go to EC-1149, "
Diagnostic Procedure" .
With GST
Follow the procedure “With CONSULT-II” above.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1121
1121 Electric throttle control
actuator A)
Electric throttle control actuator does not func-
tion properly due to the return spring malfunc-
tion.
Electric throttle control actuator
B) Throttle valve opening angle in fail-safe mode is
not in specified range.
C) ECM detect the throttle valve is stuck open.
Detected items Engine operating condition in fail-safe mode
Malfunction A The ECM controls the electric throttle actuator by regulating the throttle opening around the idle position.
The engine speed will not rise more than 2,000 rpm.
Malfunction B ECM controls the electric throttle control actuator by regulating the throttle opening to 20 degrees or less.
Malfunction C While the vehicle is driving, it slows down gradually by fuel cut. After the vehicle stops, the engine stalls.
The engine can restart in N or P position, and engine speed will not exceed 1,000 rpm or more.
SEF058Y