NISSAN X-TRAIL 2001 Service Repair Manual

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-791
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EC
MI Flashing without DTC
If the ECM is in Diagnostic Test Mode II, MI may flash when engine is running. In this case, check ECM diag-
nostic test mode. EC-791, "
HOW TO SWITCH DIAGNOSTIC TEST MODE" .
How to switch the diagnostic test (function) modes, and details of the above functions are described later, EC-
791 .
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. System readiness test (SRT) codes
6. Test values
7. Others
HOW TO SWITCH DIAGNOSTIC TEST MODE
NOTE:
●It is better to count the time accurately with a clock.
●It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit
has a malfunction.
●Always ECM returns to Diagnostic Test Mode I after ignition switch is turned “OFF”.
How to Set Diagnostic Test Mode II (Self-diagnostic Results)
1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
2. Repeat the following procedure quickly five times within 5 seconds.
a. Fully depress the accelerator pedal.
b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the MI starts
blinking.
4. Fully release the accelerator pedal.
Mode II Ignition switch in
“ON” position
Engine stoppedSELF-DIAGNOSTIC
RESULTSThis function allows DTCs and 1st trip DTCs to be read.
Engine running HEATED OXYGEN SENSOR 1
MONITORThis function allows the fuel mixture condition (lean or
rich), monitored by heated oxygen sensor 1, to be read. Diagnostic Test
ModeKEY and ENG.
StatusFunction Explanation of Function

EC-792
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
ECM has entered to Diagnostic Test Mode II (Self-diagnostic results).
How to Set Diagnostic Test Mode II (Heated Oxygen Sensor 1 Monitor)
1. Set the ECM in Diagnostic Test Mode II (Self-diagnostic results). Refer to EC-791, "How to Set Diagnostic
Test Mode II (Self-diagnostic Results)" .
2. Start Engine.
ECM has entered to Diagnostic Test Mode II (Heated oxygen sensor 1 monitor).
How to Erase Diagnostic Test Mode II (Self-diagnostic Results)
1. Set ECM in Diagnostic Test Mode II (Self-diagnostic results). Refer to EC-791, "How to Set Diagnostic
Test Mode II (Self-diagnostic Results)" .
2. Fully depress the accelerator pedal and keep it for more than 10 seconds.
The emission-related diagnostic information has been erased from the backup memory in the ECM.
3. Fully release the accelerator pedal, and confirm the DTC 0000 is displayed.
DIAGNOSTIC TEST MODE I — BULB CHECK
In this mode, the MI on the instrument panel should stay ON. If it remains OFF, check the bulb. Refer to DI-43,
"WARNING LAMPS" or see EC-991 .
DIAGNOSTIC TEST MODE I — MALFUNCTION WARNING
●These DTC numbers are clarified in Diagnostic Test Mode II (SELF-DIAGNOSTIC RESULTS)
DIAGNOSTIC TEST MODE II — SELF-DIAGNOSTIC RESULTS
In this mode, the DTC and 1st trip DTC are indicated by the number of blinks of the MI as shown below.
The DTC and 1st trip DTC are displayed at the same time. If the MI does not illuminate in diagnostic test mode
I (Malfunction warning), all displayed items are 1st trip DTCs. If only one code is displayed when the MI illumi-
nates in diagnostic test mode II (SELF-DIAGNOSTIC RESULTS), it is a DTC; if two or more codes are dis-
played, they may be either DTCs or 1st trip DTCs. DTC No. is same as that of 1st trip DTC. These unidentified
PBIB0092E
MI Condition
ON When the malfunction is detected or the ECM's CPU is malfunctioning.
OFF No malfunction.

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-793
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EC
codes can be identified by using the CONSULT-II or GST. 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
malfunction. (See EC-753, "
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-
791, "HOW TO SWITCH DIAGNOSTIC TEST MODE" .
●If the battery is disconnected, the DTC will be lost from the backup memory after approx 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.
OBD System Operation ChartEBS00MSQ
RELATIONSHIP BETWEEN MI, 1ST TRIP DTC, DTC, AND DETECTABLE ITEMS
●When a malfunction is detected for the first time, the 1st trip DTC and the 1st trip freeze frame data are
stored in the ECM memory.
●When the same malfunction is detected in two consecutive trips, the DTC and the freeze frame data are
stored in the ECM memory, and the MI will come on. For details, refer to EC-777, "
Two Trip Detection
Logic" .
SEF952W
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-794
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
●The MI will go off after the vehicle is driven 3 times with no malfunction. The drive is counted only when
the recorded driving pattern is met (as stored in the ECM). If another malfunction occurs while counting,
the counter will reset.
●The DTC and the freeze frame data will be stored until the vehicle is driven 40 times (driving pattern A)
without the same malfunction recurring (except for Misfire and Fuel Injection System). For Misfire and
Fuel Injection System, the DTC and freeze frame data will be stored until the vehicle is driven 80 times
(driving pattern C) without the same malfunction recurring. The “TIME” in “SELF-DIAGNOSTIC
RESULTS” mode of CONSULT-II will count the number of times the vehicle is driven.
●The 1st trip DTC is not displayed when the self-diagnosis results in “OK” for the 2nd trip.
SUMMARY CHART
For details about patterns “B” and “C” under “Fuel Injection System” and “Misfire”, see EC-796 .
For details about patterns “A” and “B” under “Other”, see EC-798
.
*1: Clear timing is at the moment OK is detected.
*2: Clear timing is when the same malfunction is detected in the 2nd trip. Items Fuel Injection System Misfire Other
MI (goes off) 3 (pattern B) 3 (pattern B) 3 (pattern B)
DTC, Freeze Frame Data (no
display)80 (pattern C) 80 (pattern C) 40 (pattern A)
1st Trip DTC (clear) 1 (pattern C), *1 1 (pattern C), *1 1 (pattern B)
1st Trip Freeze Frame Data
(clear)*1, *2 *1, *2 1 (pattern B)

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-795
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RELATIONSHIP BETWEEN MI, DTC, 1ST TRIP DTC AND DRIVING PATTERNS FOR “MISFIRE”
, “FUEL INJECTION SYSTEM”
*1: When the same malfunction is
detected in two consecutive trips, MI
will light up.*2: MI will go off after vehicle is driven 3
times (pattern B) without any mal-
functions.*3: When the same malfunction is
detected in two consecutive trips, the
DTC and the freeze frame data will
be stored in ECM.
*4: The DTC and the freeze frame data
will not be displayed any longer after
vehicle is driven 80 times (pattern C)
without the same malfunction. (The
DTC and the freeze frame data still
remain in ECM.)*5: When a malfunction is detected for
the first time, the 1st trip DTC and
the 1st trip freeze frame data will be
stored in ECM.*6: The 1st trip DTC and the 1st trip
freeze frame data will be cleared at
the moment OK is detected.
*7: When the same malfunction is
detected in the 2nd trip, the 1st trip
freeze frame data will be cleared.*8: 1st trip DTC will be cleared when
vehicle is driven once (pattern C)
without the same malfunction after
DTC is stored in ECM.
SEF392SA

EC-796
[QR20(WITH EURO-OBD)]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EXPLANATION FOR DRIVING PATTERNS FOR “MISFIRE TION>”, “FUEL INJECTION SYSTEM”

Driving pattern B means the vehicle operation as follows:
All components and systems should be monitored at least once by the OBD system.
●The B counter will be cleared when the malfunction is detected once regardless of the driving pattern.
●The B counter will be counted up when driving pattern B is satisfied without any malfunction.
●The MI will go off when the B counter reaches 3. (*2 in “OBD SYSTEM OPERATION CHART”)

Driving pattern C means the vehicle operation as follows:
1. The following conditions should be satisfied at the same time:
Engine speed: (Engine speed in the freeze frame data) ±375 rpm
Calculated load value: (Calculated load value in the freeze frame data) x (1±0.1) [%]
Engine coolant temperature (T) condition:
●When the freeze frame data shows lower than 70°C (158°F), “T” should be lower than 70°C (158°F).
●When the freeze frame data shows higher than or equal to 70°C (158°F), “T” should be higher than or
equal to 70°C (158°F).
Example:
If the stored freeze frame data is as follows:
Engine speed: 850 rpm, Calculated load value: 30%, Engine coolant temperature: 80°C (176°F)
To be satisfied with driving pattern C, the vehicle should run under the following conditions:
Engine speed: 475 - 1,225 rpm, Calculated load value: 27 - 33%, Engine coolant temperature: more than 70°C
(158°F)
●The C counter will be cleared when the malfunction is detected regardless of (1).
●The C counter will be counted up when (1) is satisfied without the same malfunction.
●The DTC will not be displayed after C counter reaches 80.
●The 1st trip DTC will be cleared when C counter is counted once without the same malfunction after DTC
is stored in ECM.

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-797
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RELATIONSHIP BETWEEN MI, DTC, 1ST TRIP DTC AND DRIVING PATTERNS EXCEPT FOR
“MISFIRE ”, “FUEL INJECTION SYSTEM”
*1: When the same malfunction is
detected in two consecutive trips, MI
will light up.*2: MI will go off after vehicle is driven 3
times (pattern B) without any mal-
functions.*3: When the same malfunction is
detected in two consecutive trips, the
DTC and the freeze frame data will
be stored in ECM.
*4: The DTC and the freeze frame data
will not be displayed any longer after
vehicle is driven 40 times (pattern A)
without the same malfunction.
(The DTC and the freeze frame data
still remain in ECM.)*5: When a malfunction is detected for
the first time, the 1st trip DTC and
the 1st trip freeze frame data will be
stored in ECM.*6: 1st trip DTC will be cleared after
vehicle is driven once (pattern B)
without the same malfunction.
*7: When the same malfunction is
detected in the 2nd trip, the 1st trip
freeze frame data will be cleared.
SEF393SA

EC-798
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
EXPLANATION FOR DRIVING PATTERNS EXCEPT FOR “MISFIRE DETERIORATION>”, “FUEL INJECTION SYSTEM”

●The A counter will be cleared when the malfunction is detected regardless of (1) - (4).
●The A counter will be counted up when (1) - (4) are satisfied without the same malfunction.
●The DTC will not be displayed after the A counter reaches 40.

Driving pattern B means the vehicle operation as follows:
All components and systems should be monitored at least once by the OBD system.
●The B counter will be cleared when the malfunction is detected once regardless of the driving pattern.
●The B counter will be counted up when driving pattern B is satisfied without any malfunctions.
●The MI will go off when the B counter reaches 3 (*2 in “OBD SYSTEM OPERATION CHART”).
AEC574

TROUBLE DIAGNOSIS
EC-799
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TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionEBS00MSR
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 malfunction that occurs inter-
mittently rather than continuously. Most intermittent malfunctions 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 GST) or a circuit tester connected should
be performed. Follow the “Work Flow” on EC-800
.
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 exam-
ple on EC-802
should be used.
Start your diagnosis by looking for “conventional” incidents first. This
will help troubleshoot driveability incidents on an electronically con-
trolled engine vehicle.
MEF036D
SEF233G
SEF234G

EC-800
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TROUBLE DIAGNOSIS
WORK FLOW
Flow Chart
*1 If time data of “SELF-DIAG
RESULTS” is other than “0” or “[1t]”,
perform EC-847, "
TROUBLE DIAG-
NOSIS FOR INTERMITTENT INCI-
DENT" .*2 If the incident cannot be verified, per-
form EC-847, "
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-848, "POWER SUPPLY
CIRCUIT FOR ECM" .
*4 If malfunctioning part cannot be
detected, perform EC-847, "
TROU-
BLE DIAGNOSIS FOR INTERMIT-
TENT INCIDENT" .*5EC-786
*6EC-843
MBIB0159E