NISSAN X-TRAIL 2003 Electronic Repair Manual

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

EC-408
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TROUBLE DIAGNOSIS
WORK FLOW
Flow Chart
*1EC-411*2 If time data of “SELF-DIAG
RESULTS” is other than “0” or “[1t]”,
performEC-453, "
TROUBLE DIAG-
NOSIS FOR INTERMITTENT INCI-
DENT".*3 If the incident cannot be verified, per-
formEC-453, "
TROUBLE DIAGNO-
SIS FOR INTERMITTENT INCIDENT"
.
*4 If the on board diagnostic system can-
not be performed, check main power
supply and ground circuit. Refer to
EC-454, "
POWER SUPPLY CIRCUIT
FOR ECM".*5 If malfunctioning part cannot be
detected, performEC-453, "
TROU-
BLE DIAGNOSIS FOR INTERMIT-
TENT INCIDENT".*6EC-449
PBIB0680E

TROUBLE DIAGNOSIS
EC-409
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EC
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-410
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TROUBLE DIAGNOSIS
lFuel filler cap was left off or incorrectly screwed on, allowing fuel to evaporate into the atmosphere.
Worksheet Sample
DTC Inspection Priority ChartEBS00BMV
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:
If DTC U1000 is displayed with other DTC, first perform the trouble diagnosis for DTC U1000. Refer to
EC-460
.
MTBL0017

TROUBLE DIAGNOSIS
EC-411
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EC
Fail-safe ChartEBS00BMW
The ECM enters fail-safe mode, if any of the following malfunctions is detected due to the open or short circuit.
When the ECM enters the fail-safe mode, the MI illuminates.
Priority Detected items (DTC)
1
lU1000 CAN communication line
lP0102 P0103 Mass air flow sensor
lP0117 P0118 Engine coolant temperature sensor
lP0120 Throttle position sensor
lP0121 Accelerator pedal position sensor
lP0327 P0328 Knock sensor
lP0335 Crankshaft position sensor (POS)
lP0340 Camshaft position sensor (PHASE)
lP0500 Vehicle speed sensor
lP0605 ECM
2
lP0134 Heated oxygen sensor 1
lP0550 Power steering pressure sensor
lP0650 MI
lP1065 ECM power supply
lP1122 Electric throttle control function
lP1123 Throttle control motor relay
lP1212 ESP/TCS/ABS communication line
lP1805 Brake switch
3
lP1121 Electric throttle control actuator
lP1217 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 Start40°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 cool-
ing fan operates while engine is running.
P0120 Throttle position sensor cir-
cuitECM controls the electric throttle control actuator by regulating the throttle opening to
small range.
Therefore, acceleration will be poor.
Condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration

EC-412
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TROUBLE DIAGNOSIS
Basic Inspection
EBS00BMX
1.INSPECTION START
1. Check service records for any recent repairs that may indicate a related problem, 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 or GST.
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

TROUBLE DIAGNOSIS
EC-413
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3.CHECK TARGET IDLE SPEED
With CONSULT-II
1. Run engine at about 2,000 rpm for about 2 minutes under no-load.
2. Rev engine (2,000 to 3,000 rpm) two or three times under no-
load, then run engine at idle speed for about 1 minute.
3. Read idle speed in “DATA MONITOR” mode with CONSULT-II.
Wi t h ou t C O N S U LT-I I
1. Run engine at about 2,000 rpm for about 2 minutes under no-load.
2. Rev engine (2,000 to 3,000 rpm) two or three times under no-load, then run engine at idle speed for about
1 minute.
3. Check idle speed.
OK or NG
OK >> GO TO 10.
NG >> GO TO 4.
4.PERFORM ACCELERATOR PEDAL RELEASED POSITION LEARNING
1. Stop engine.
2. PerformEC-396, "
Accelerator Pedal Released Position Learning".
>> GO TO 5.
5.PERFORM THROTTLE VALVE CLOSED POSITION LEARNING
1. Stop engine.
2. PerformEC-396, "
Throttle Valve Closed Position Learning".
>> GO TO 6.
SEF978U
M/T: 650±50 rpm
A/T: 700±50 rpm (in "P" or "N" position)
SEF058Y
M/T: 650±50 rpm
A/T: 700±50 rpm (in "P" or "N" position)

EC-414
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TROUBLE DIAGNOSIS
6.PERFORM IDLE AIR VOLUME LEARNING
Refer toEC-396, "
Idle Air Volume Learning".
CMPLT or INCMP
CMPLT>>GOTO7.
INCMP >> 1. Follow the construction of “Idle Air Volume Learning”.
2. GO TO 4.
7.CHECK TARGET IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Read idle speed in “DATA MONITOR” mode with CONSULT-II.
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
OK or NG
OK >> GO TO 10.
NG >> GO TO 8.
8.DETECT MALFUNCTIONING PART
Check the Following.
lCheck camshaft position sensor (PHASE) and circuit. Refer toEC-507.
lCheck crankshaft position sensor (POS) and circuit. Refer toEC-501.
OK or NG
OK >> GO TO 9.
NG >> 1. Repair or replace.
2. GO TO 4.
9.CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of a problem, but
this is the rarely the case.)
2. Perform initialization of NATS system and registration of NATS ignition key IDs. Refer toEC-403, "
NATS
(Nissan Anti-theft System)".
>> GO TO 4. Which is the result CMPLT or INCMP
M/T: 650±50 rpm
A/T: 700±50 rpm (in "P" or "N" position)
M/T: 650±50 rpm
A/T: 700±50 rpm (in "P" or "N" position)

TROUBLE DIAGNOSIS
EC-415
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10.CHECK IGNITION TIMING
1. Run engine at idle.
2. Check ignition timing with a timing light.
OK or NG
OK >>INSPECTION END
NG >> GO TO 11.
11 .ACCELERATOR PEDAL RELEASED POSITION LEARNING
1. Stop engine.
2. PerformEC-396, "
Accelerator Pedal Released Position Learning".
>> GO TO 12.
12.PERFORM THROTTLE VALVE CLOSED POSITION LEARNING
1. Stop engine.
2. PerformEC-396, "
Throttle Valve Closed Position Learning".
>> GO TO 13.
13.PERFORM IDLE AIR VOLUME LEARNING
Refer toEC-396, "
Idle Air Volume Learning".
CMPLT or INCMP
CMPLT>>GOTO14.
INCMP >> 1. Follow the construction of “Idle Air Volume Learning”.
2. GO TO 4.
14.CHECK TARGET IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Read idle speed in “DATA MONITOR” mode with CONSULT-II.
Wi t h ou t C O N S U LT-I I
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
OK or NG
OK >> GO TO 15.
NG >> GO TO 17.M/T: 14±5°BTDC
A/T: 16±5°BTDC (in "P" or "N" position)
Which is the result CMPLT or INCMP
M/T: 650±50 rpm
A/T: 700±50 rpm (in "P" or "N" position)
M/T: 650±50 rpm
A/T: 700±50 rpm (in "P" or "N" position)

EC-416
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TROUBLE DIAGNOSIS
15.CHECK IGNITION TIMING AGAIN
1. Run engine at idle.
2. Check ignition timing with a timing light.
OK or NG
OK >>INSPECTION END
NG >> GO TO 16.
16.CHECK TIMING CHAIN INSTALLATION
Check timing chain installation. Refer toEM-43, "
TIMING CHAIN".
OK or NG
OK >> GO TO 17.
NG >> 1. Repair the timing chain installation.
2. GO TO 4.
17.DETECT MALFUNCTIONING PART
Check the following.
lCheck camshaft position sensor (PHASE) and circuit. Refer toEC-507.
lCheck crankshaft position sensor (POS) and circuit. Refer toEC-501.
OK or NG
OK >> GO TO 18.
NG >> 1. Repair or replace.
2. GO TO 4.
18.CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of a problem, but
this is the rarely the case.)
2. Perform initialization of NATS system and registration of NATS ignition key IDs. Refer toEC-403, "
NATS
(Nissan Anti-theft System)".
>> GO TO 4. M/T: 14±5°BTDC
A/T: 16±5°BTDC (in "P" or "N" position)