ENGINE CONTROL SYSTEM
EC-393
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EC
lWhen the accelerator pedal is fully depressed.
lWhen cranking the engine.
lAt high engine speeds.
lWhen the engine coolant temperature becomes excessively high.
lWhen operating power steering during low engine speed or low vehicle speed.
lWhen engine speed is excessively low.
lWhen refrigerant pressure is excessively low or high.
Fuel Cut Control (at No Load and High Engine Speed)EBS00BEX
INPUT/OUTPUT SIGNAL CHART
SYSTEM DESCRIPTION
If the engine speed is above 1,800 rpm with no load (for example, in neutral and engine speed 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 operate until the engine speed reaches 1,500 rpm, then fuel cut is cancelled.
NOTE:
This function is different from deceleration control listed under “Multiport Fuel Injection (MFI) System”,EC-389
.
CAN communicationEBS00BEY
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
FOR A/T MODELS
System Diagram
Input/Output Signal Chart
T: Transmit R: Receive Sensor Input Signal to ECMECM
functionActuator
Park/neutral position (PNP) switch Neutral position
Fuel cut
controlFuel injectors Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS) Engine speed
Wheel sensor Vehicle speed
SKIA0884E
Signals ECM TCM
Engine speed signal T R
Engine coolant temperature signal T R
BASIC SERVICE PROCEDURE
EC-397
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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.
lBattery voltage: More than 12.9V (At idle)
lEngine coolant temperature: 70 - 100°C (158 - 212°F)
lPNP switch: ON
lElectric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, set lighting switch to the 1st position to light
only small lamps.
lSteering wheel: Neutral (Straight-ahead position)
lVehicle speed: Stopped
lTransmission: Warmed-up
For A/T models with CONSULT-II, drive vehicle until “FLUID TEMP SE” in “DATA MONITOR” mode of “A/
T” system indicates less than 0.9V.
For A/T models without CONSULT-II and M/T models, drive vehicle for 10 minutes.
OPERATION PROCEDURE
With CONSULT-II
1. PerformEC-396, "Accelerator Pedal Released Position Learning".
2. PerformEC-396, "
Throttle Valve Closed Position Learning".
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic “PRE-CONDITIONING” (previously mentioned) are in good
order.
5. Select “IDLE AIR VOL LEARN” in “WORK SUPPORT” mode.
6. Touch “START” and wait 20 seconds.
SEF452Y
SEF454Y
BASIC SERVICE PROCEDURE
EC-399
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DIAGNOSTIC PROCEDURE
If idle air volume learning cannot be performed successfully, proceed as follows:
1.Check that throttle valve is fully closed.
2.Check PCV valve operation.
3.Check that downstream of throttle valve is free from air leakage.
4.When the above three items check out OK, engine component parts and their installation condi-
tion are questionable. Check and eliminate the cause of the problem.
It is useful to performEC-449, "
TROUBLE DIAGNOSIS - SPECIFICATION VALUE".
5.If any of the following conditions occur after the engine has started, eliminate the cause of the
problem and perform “Idle air volume learning” all over again:
–Engine stalls.
–Erroneous idle.
Fuel Pressure CheckEBS00BF2
FUEL PRESSURE RELEASE
Before disconnecting fuel line, release fuel pressure from fuel line to eliminate danger.
With CONSULT-II
1. Turn ignition switch “ON”.
2. Perform “FUEL PRESSURE RELEASE” in “WORK SUPPORT”
mode with CONSULT-II.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel
pressure.
5. Turn ignition switch “OFF”.
Without CONSULT-II
1. Remove fuel pump fuse located in fuse box.
2. Start engine.
3. After engine stalls, crank it two or three times to release all fuel
pressure.
4. Turn ignition switch “OFF”.
5. Reinstall fuel pump fuse after servicing fuel system.
FUEL PRESSURE CHECK
CAUTION:
lThe fuel hose connection method used when taking fuel pressure check must not be used for
other purposes.
lTake care for not to scratch and not to put debris around connection area when servicing, so that
the quick connector keeps sealability with O-rings inside.
1. Release fuel pressure to zero. Refer toEC-399, "
FUEL PRESSURE RELEASE".
2. Prepare fuel hose for fuel pressure check, and connect fuel pressure gauge.
lUse suitable fuel hose for fuel pressure check (genuine NISSAN fuel hose without quick connector).
lTo avoid unnecessary force or tension to hose, use moderately long fuel hose for fuel pressure check.
lDo not use the fuel hose for checking fuel pressure with damage or cracks on it.
lUse Pressure Gauge to check fuel pressure.
SEF214Y
PBIB0508E
TROUBLE DIAGNOSIS
EC-407
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TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionEBS00BMU
INTRODUCTION
The engine has an ECM to control major systems such as fuel con-
trol, ignition control, idle air control system, etc. The ECM accepts
input signals from sensors and instantly drives actuators. It is essen-
tial that both input and output signals are proper and stable. At the
same time, it is important that there are no problems such as vac-
uum leaks, fouled spark plugs, or other problems with the engine.
It is much more difficult to diagnose a problem that occurs intermit-
tently rather than continuously. Most intermittent problems are
caused by poor electric connections or improper wiring. In this case,
careful checking of suspected circuits may help prevent the replace-
ment of good parts.
A visual check only may not find the cause of the problems. A road
test with CONSULT-II (or GST) or a circuit tester connected should
be performed. Follow the “Work Flow” onEC-408
.
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such problems, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “Diagnostic Worksheet” like the exam-
ple onEC-410
should be used.
Start your diagnosis by looking for “conventional” problems first. This
will help troubleshoot driveability problems on an electronically con-
trolled engine vehicle.
MEF036D
SEF233G
SEF234G
TROUBLE DIAGNOSIS
EC-409
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Description for Work Flow
DIAGNOSTIC WORKSHEET
Description
There are many operating conditions that lead to the malfunction of
engine components. A good grasp of such conditions can make trou-
bleshooting faster and more accurate.
In general, each customer feels differently about a problem. It is
important to fully understand the symptoms or conditions for a cus-
tomer complaint.
Utilize a diagnostic worksheet like the one on the next page in order
to organize all the information for troubleshooting.
Some conditions may cause the MI to come on steady or blink and
DTC to be detected. Examples:
lVehicle ran out of fuel, which caused the engine to misfire.
STEP DESCRIPTION
STEP IGet detailed information about the conditions and the environment when the incident/symptom occurred using the
“DIAGNOSTIC WORK SHEET”,EC-409
.
STEP IIBefore confirming the concern, check and write down (print out using CONSULT-II or GST) the (1st trip) DTC and the
(1st trip) freeze frame data, then erase the DTC and the data. (Refer toEC-402
.) The (1st trip) DTC and the (1st trip)
freeze frame data can be used when duplicating the incident at STEP III & IV.
If the incident cannot be verified, performEC-453, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT".
Study the relationship between the cause, specified by (1st trip) DTC, and the symptom described by the customer.
(The “Symptom Matrix Chart” will be useful. SeeEC-417
.)
Also check related service bulletins for information.
STEP IIITry to confirm the symptom and under what conditions the incident occurs.
The “DIAGNOSTIC WORK SHEET” and the freeze frame data are useful to verify the incident. Connect CONSULT-II
to the vehicle in DATA MONITOR (AUTO TRIG) mode and check real time diagnosis results.
If the incident cannot be verified, performEC-453, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT".
If the malfunction code is detected, skip STEP IV and perform STEP V.
STEP IVTry to detect the (1st trip) DTC by driving in (or performing) the “DTC Confirmation Procedure”. Check and read the
(1st trip) DTC and (1st trip) freeze frame data by using CONSULT-II or GST.
During the (1st trip) DTC verification, be sure to connect CONSULT-II to the vehicle in DATA MONITOR (AUTO TRIG)
mode and check real time diagnosis results.
If the incident cannot be verified, performEC-453, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT".
In case the “DTC Confirmation Procedure” is not available, perform the “Overall Function Check” instead. The (1st
trip) DTC cannot be displayed by this check, however, this simplified “check” is an effective alternative.
The “NG” result of the “Overall Function Check” is the same as the (1st trip) DTC detection.
STEP VTake the appropriate action based on the results of STEP I through IV.
If the malfunction code is indicated, proceed to TROUBLE DIAGNOSIS FOR DTC PXXXX.
If the normal code is indicated, proceed to the BASIC INSPECTION. (Refer toEC-412
.) Then perform inspections
according to the Symptom Matrix Chart. (Refer toEC-417
.)
STEP VIIdentify where to begin diagnosis based on the relationship study between symptom and possible causes. Inspect the
system for mechanical binding, loose connectors or wiring damage using (tracing) “Harness Layouts”.
Gently shake the related connectors, components or wiring harness with CONSULT-II set in “DATA MONITOR
(AUTO TRIG)” mode.
Check the voltage of the related ECM terminals or monitor the output data from the related sensors with CONSULT-II.
Refer toEC-427
,EC-443.
The “Diagnostic Procedure” in EC section contains a description based on open circuit inspection. A short circuit
inspection is also required for the circuit check in the Diagnostic Procedure. For details, refer to “Circuit Inspection” in
GI-24, "
How to Perform Efficient Diagnosis for an Electrical Incident".
Repair or replace the malfunction parts.
If malfunctioning part cannot be detected, performEC-453, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCI-
DENT".
STEP VIIOnce you have repaired the circuit or replaced a component, you need to run the engine in the same conditions and
circumstances which resulted in the customer's initial complaint.
Perform the “DTC Confirmation Procedure” and confirm the normal code [DTC No. P0000] is detected. If the incident
is still detected in the final check, perform STEP VI by using a method different from the previous one.
Before returning the vehicle to the customer, be sure to erase the unnecessary (already fixed) (1st trip) DTC in ECM.
(Refer toEC-402, "
HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION".)
SEF907L
EC-434
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TROUBLE DIAGNOSIS
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
CONSULT-II FunctionEBS00BN3
FUNCTION
*1 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. Others11 5 B / YThrottle control motor
ground[Engine is running]
lIdle speedApproximately 0V
11 6 GThrottle control motor
(Close)[Ignition switch "ON"]
lGear position is "D" (A/T model)
lGear position is "1st" (M/T model)
lAccelerator pedal is releasing0 - 14V TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
PBIB0534E
Diagnostic test mode Function
Work supportThis mode enables a technician to adjust some devices faster and more accurately by following the
indications on the CONSULT-II unit.
Self-diagnostic resultsSelf-diagnostic results such as 1st trip DTC, DTCs and 1st trip freeze frame data or freeze frame data
can be read and erased quickly.*1
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.
Active testDiagnostic Test Mode in which CONSULT-II drives some actuators apart from the ECMs and also
shifts some parameters in a specified range.
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.
TROUBLE DIAGNOSIS
EC-435
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ENGINE CONTROL COMPONENT PARTS/CONTROL SYSTEMS APPLICATION
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-II screen in freeze frame data
mode only if a 1st trip DTC or DTC is detected. For details, refer toEC-402
.
CONSULT-II INSPECTION PROCEDURE
1. Turn ignition switch OFF.
ItemDIAGNOSTIC TEST MODE
WORK
SUPPORTSELF-DIAGNOSTIC
RESULTS
DATA
MONI-
TORDATA
MONI-
TOR
(SPEC)ACTIVE
TEST
DTC*1FREEZE
FRAME
DATA*2
ENGINE CONTROL COMPONENT PARTS
INPUT
Crankshaft position sensor (POS)´´´´
Camshaft position sensor (PHASE)´
Mass air flow sensor´´´
Engine coolant temperature sensor´´´´´
Heated oxygen sensor 1´´´
Heated oxygen sensor 2´´
Wheel sensor (Vehicle speed signal)´´´´
Accelerator pedal position sensor´´´
Throttlepositionsensor´´´
Intake air temperature sensor´´
Knock sensor´
Refrigerant pressure sensor´´
Ignition switch (start signal)´´
Closed throttle position switch (accelera-
tor pedal position sensor signal)´´
Air conditioner switch´´
Park/neutral position (PNP) switch´´
Stop lamp switch´´´
Power steering pressure sensor´´´
Battery voltage´´
Load signal´´
ENGINE CONTROL COMPONENT PARTS
OUTPUT
Injectors´´ ´
Power transistor (Ignition timing)´´ ´
Throttle control motor relay´´´
EVAP canister purge volume control sole-
noid valve´´ ´
Air conditioner relay´´
Fuel pump relay´´´´
Cooling fan relay´´´´
Heated oxygen sensor 1 heater´´
Heated oxygen sensor 2 heater´´
Intake valve timing control solenoid valve´´ ´
Calculated load value´´´
EC-436
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TROUBLE DIAGNOSIS
2. Connect “CONSULT-II” to data link connector, which is located
under LH dash panel near the fuse box cover.
3. Turn ignition switch ON.
4. Touch “START”.
5. Touch “ENGINE”.
6. Perform each diagnostic test mode according to each service
procedure.
For further information, see the CONSULT-II Operation Manual.
WORK SUPPORT MODE
Work Item
PBIB0376E
PBR455D
SEF995X
SEF824Y
WORK ITEM CONDITION USAGE
FUEL PRESSURE RELEASE
lFUEL 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
lTHE IDLE AIR VOLUME THAT KEEPS THE ENGINE
WITHIN THE SPECIFIED RANGE IS MEMORIZED IN
ECM.When learning the idle air volume