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ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-519
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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.
Page 898 of 4179
![NISSAN X-TRAIL 2003 Service Repair Manual EC-520
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TROUBLE DIAGNOSIS
TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionEBS010X4
INTRODUCTION
The engine has an ECM to control major systems such as fuel con-
trol, NISSAN X-TRAIL 2003 Service Repair Manual EC-520
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TROUBLE DIAGNOSIS
TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionEBS010X4
INTRODUCTION
The engine has an ECM to control major systems such as fuel con-
trol,](/manual-img/5/57404/w960_57404-897.png)
EC-520
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TROUBLE DIAGNOSIS
TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionEBS010X4
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 malfunctions such as vac-
uum leaks, fouled spark plugs, or other malfunctions with the engine.
It is much more difficult to diagnose a incident that occurs intermit-
tently rather than continuously. Most intermittent incidents 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 incidents. A road
test with CONSULT-II or a circuit tester connected should be per-
formed. Follow the Work Flow on EC-521
.
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 incidents, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A Diagnostic Worksheet like the example
on EC-523
should be used.
Start your diagnosis by looking for conventional malfunctions first.
This will help troubleshoot driveability malfunctions on an electroni-
cally controlled engine vehicle.
MEF036D
SEF233G
SEF234G
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TROUBLE DIAGNOSIS
EC-521
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WORK FLOW
Flow Chart
*1 If time data of “SELF-DIAG
RESULTS” is other than [0] or [1t],
perform EC-570, "
TROUBLE DIAG-
NOSIS FOR INTERMITTENT INCI-
DENT" .*2 If the incident cannot be verified, per-
form EC-570, "
TROUBLE DIAGNO-
SIS FOR INTERMITTENT
INCIDENT" .*3 If the on board diagnostic system
cannot be performed, check main
power supply and ground circuit.
Refer to EC-571, "POWER SUPPLY
AND GROUND CIRCUIT" .
*4 If malfunctioning part cannot be
detected, perform EC-570, "
TROU-
BLE DIAGNOSIS FOR INTERMIT-
TENT INCIDENT" .*5EC-566
MBIB0178E
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![NISSAN X-TRAIL 2003 Service Repair Manual EC-522
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TROUBLE DIAGNOSIS
Description for Work Flow
DIAGNOSTIC WORKSHEET
Description
There are many operating conditions that lead to the malfunction of
engine components. A g NISSAN X-TRAIL 2003 Service Repair Manual EC-522
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TROUBLE DIAGNOSIS
Description for Work Flow
DIAGNOSTIC WORKSHEET
Description
There are many operating conditions that lead to the malfunction of
engine components. A g](/manual-img/5/57404/w960_57404-899.png)
EC-522
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TROUBLE DIAGNOSIS
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 incident. 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:
Vehicle 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-522
.
STEP IIBefore confirming the concern, check and write down (print out using CONSULT-II) the (1st trip) DTC and the (1st
trip) freeze frame data, then erase the DTC and the data. (Refer to EC-514
.) 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, perform EC-570, "
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. See EC-532
.)
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, perform EC-570, "
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.
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, perform EC-570, "
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 to EC-526
.) Then perform inspections
according to the Symptom Matrix Chart. (Refer to EC-532
.)
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 to EC-543
, EC-561 .
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-23, "
How to Perform Efficient Diagnosis for an Electrical Incident" .
Repair or replace the malfunction parts.
If malfunctioning part cannot be detected, perform EC-570, "
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 to EC-514, "
HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION" .)
SEF907L
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TROUBLE DIAGNOSIS
EC-523
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Fuel filler cap was left off or incorrectly screwed on, allowing fuel to evaporate into the atmosphere.
Worksheet Sample
DTC Inspection Priority ChartEBS010X5
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-579
.
MTBL0017
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![NISSAN X-TRAIL 2003 Service Repair Manual EC-524
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TROUBLE DIAGNOSIS
Fail-safe ChartEBS010X6
When the DTC listed bellow is detected, the ECM enters fail-safe mode and the MI lights up.
Priority Detected items (DTC)
1
NISSAN X-TRAIL 2003 Service Repair Manual EC-524
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TROUBLE DIAGNOSIS
Fail-safe ChartEBS010X6
When the DTC listed bellow is detected, the ECM enters fail-safe mode and the MI lights up.
Priority Detected items (DTC)
1
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EC-524
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TROUBLE DIAGNOSIS
Fail-safe ChartEBS010X6
When the DTC listed bellow is detected, the ECM enters fail-safe mode and the MI lights up.
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
P1211 TCS control unit
P1212 TCS communication line
P1720 Vehicle speed sensor
P1805 Brake switch
3
P0011 Intake valve timing control
P1121 Electric throttle control actuator
P1217 Engine over temperature (OVERHEAT)
DTC No. Detected items Engine operating condition in fail-safe mode
P0102
P0103Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0117
P0118Engine coolant tempera-
ture sensor circuitEngine coolant temperature will be determined by ECM based on the time after turning
ignition switch ON or START.
CONSULT-II displays the engine coolant temperature decided by ECM.
ConditionEngine coolant temperature decided
(CONSULT-II display)
Just as ignition switch is turned ON or START 40°C (104°F)
More than approx. 4 minutes after ignition ON
or START80°C (176°F)
Except as shown above40 - 80°C (104 - 176°F)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cooling
fan operates while engine is running.
P0122
P0123
P0221
P0222
P2135Throttle position sensor The ECM controls the electric throttle control actuator in regulating the throttle opening in
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal
condition.
So, the acceleration will be poor.
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![NISSAN X-TRAIL 2003 Service Repair Manual TROUBLE DIAGNOSIS
EC-525
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When there is an open circuit on MI circuit, the ECM can not warn the driver by lighting up MI when there is
trouble on eng NISSAN X-TRAIL 2003 Service Repair Manual TROUBLE DIAGNOSIS
EC-525
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When there is an open circuit on MI circuit, the ECM can not warn the driver by lighting up MI when there is
trouble on eng](/manual-img/5/57404/w960_57404-902.png)
TROUBLE DIAGNOSIS
EC-525
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When there is an open circuit on MI circuit, the ECM can not warn the driver by lighting up MI when there is
trouble on engine control system. Therefore, when Electrical controlled throttle and part of the ECM related
diagnoses are continuously detected as NG for 5-trips, ECM warns the driver that engine control system has
trouble and MI circuit is open by means of operating fail-safe function.
The fail-safe function also operates when above diagnoses except MI circuit are detected and demands the
driver to repair the trouble.
P1121 Electric throttle control
actuator(When electric throttle control actuator does not function properly due to the return spring
malfunction:)
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.
(When throttle valve opening angle in fail-safe mode is not in specified range:)
ECM controls the electric throttle control actuator by regulating the throttle opening to 20
degrees or less.
(ECM detect the throttle valve is stuck open:)
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.
P1122 Electric throttle control
functionECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1124
P1126Throttle control motor relay ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1128 Throttle control motor ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1229 Sensor power supply ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P2122
P2123
P2127
P2128
P2138Accelerator pedal position
sensorThe ECM controls the electric throttle control actuator in regulating the throttle opening in
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal
condition.
So, the acceleration will be poor. DTC No. Detected items Engine operating condition in fail-safe mode
Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut
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![NISSAN X-TRAIL 2003 Service Repair Manual EC-526
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TROUBLE DIAGNOSIS
Basic InspectionEBS010X7
1. INSPECTION START
1. Check service records for any recent repairs that may indicate a related malfunction, or a current ne NISSAN X-TRAIL 2003 Service Repair Manual EC-526
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TROUBLE DIAGNOSIS
Basic InspectionEBS010X7
1. INSPECTION START
1. Check service records for any recent repairs that may indicate a related malfunction, or a current ne](/manual-img/5/57404/w960_57404-903.png)
EC-526
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TROUBLE DIAGNOSIS
Basic InspectionEBS010X7
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
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