2001 NISSAN X-TRAIL sensor

EC-134
[QR25(WITH EURO-OBD)]
DTC P0037, P0038 HO2S2 HEATER
On Board Diagnosis Logic
EBS00M22
DTC Confirmation ProcedureEBS00M23
NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch “OFF” and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is between 10.5V and 16V at
idle.
WITH CONSULT-II
1. Turn ignition switch “ON” and select “DATA MONITOR” mode with CONSULT-II.
2. Start engine and warm it up to the normal operating temperature.
3. Turn ignition switch ″OFF″ and wait at least 10 seconds.
4. Start engine and keep the engine speed between 3,500 and
4,000 rpm for at least one minute under no load.
5. Let engine idle for one minute.
6. If 1st trip DTC is detected, go to EC-136, "
Diagnostic Procedure"
.
WITH GST
1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch “OFF”and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least one minute under no
load.
4. Let engine idle for one minute.
5. Turn ignition switch “OFF”and wait at least 10 seconds.
6. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least one minute under no
load.
7. Let engine idle for one minute.
8. Select “MODE 3” with GST.
9. If DTC is detected, go to EC-136, "
Diagnostic Procedure" .
●When using GST, “DTC Confirmation Procedure” should be performed twice as much as when
using CONSULT-II because GST cannot display MODE 7 (1st trip DTC) concerning this diagnosis.
Therefore, using CONSULT-II is recommended.
DTC No.Trouble diagnosis
nameDTC detecting condition Possible cause
P0037
0037Heated oxygen
sensor 2 heater
control circuit lowThe current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the heated oxygen sensor 1 heater.)
●Harness or connectors
(The heated oxygen sensor 1 heater circuit is
open or shorted.)
●Heater oxygen sensor 1 heater
P0038
0038Heated oxygen
sensor 2 heater
control circuit highThe current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to
ECM through the heated oxygen sensor 1
heater.)
●Harness or connectors
(The heated oxygen sensor 1 heater circuit is
shorted.)
●Heater oxygen sensor 1 heater
SEF174Y

EC-136
[QR25(WITH EURO-OBD)]
DTC P0037, P0038 HO2S2 HEATER
Diagnostic Procedure
EBS00M25
1. CHECK HO2S2 POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”.
2. Disconnect heated oxygen sensor 2 harness connector.
3. Turn ignition switch “ON”.
4. Check voltage between HO2S2 terminal 4 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. DETECT MALFUNCTIONING PART
Check the following.
●Harness connectors E60, F36
●Fuse block (J/B) connector E103
●10A fuse
●Harness for open or short between heated oxygen sensor 2 and fuse
>> Repair harness or connectors.
3. CHECK HO2S2 OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch “OFF”.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 4 and HO2S2 terminal 1.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connectors.
PBIB0500E
Voltage: Battery voltage
PBIB0541E
Continuity should exist.

DTC P0037, P0038 HO2S2 HEATER
EC-137
[QR25(WITH EURO-OBD)]
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4.CHECK HEATED OXYGEN SENSOR 2 HEATER
Refer to EC-137, "
Component Inspection" .
OK or NG
OK >> GO TO 5.
NG >> Replace malfunctioning heated oxygen sensor 2.
5.CHECK INTERMITTENT INCIDENT
Refer to EC-115, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionEBS00M26
HEATED OXYGEN SENSOR 2 HEATER
1. Check resistance between HO2S2 terminals as follows.
2. If NG, replace heated oxygen sensor 2.
CAUTION:
●Discard any heated oxygen sensor which has been dropped
from a height of more than 0.5 m (19.7 in) onto a hard sur-
face such as a concrete floor; use a new one.
●Before installing new oxygen sensor, clean exhaust system
threads using Oxygen Sensor Thread Cleaner tool J-43897-
18 or J-43897-12 and approved anti-seize lubricant.
Removal and InstallationEBS00M27
HEATED OXYGEN SENSOR 2
Refer to EX-2, "EXHAUST SYSTEM" .
Terminal No. Resistance
1 and 4 2.3 - 4.3 Ω at 25°C (77°F)
2 and 1, 3, 4
∞Ω
(Continuity should not exist)
3 and 1, 2, 4
PBIB0542E

EC-138
[QR25(WITH EURO-OBD)]
DTC P0102, P0103 MAF SENSOR
DTC P0102, P0103 MAF SENSOR
PFP:22680
Component DescriptionEBS00M28
The mass air flow sensor is placed in the stream of intake air. It mea-
sures the intake flow rate by measuring a part of the entire intake
flow. It consists of a hot film that is supplied with electric current from
the ECM. The temperature of the hot film is controlled by the ECM a
certain amount. The heat generated by the hot film is reduced as the
intake air flows around it. The more air, the greater the heat loss.
Therefore, the ECM must supply more electric current to maintain
the temperature of the hot film as air flow increases. The ECM
detects the air flow by means of this current change.
CONSULT-II Reference Value in Data Monitor ModeEBS00M29
Specification data are reference values.
ECM Terminals and Reference ValueEBS00M2A
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis LogicEBS00M2B
These self-diagnoses have the one trip detection logic.
SEC266C
MONITOR ITEM CONDITION SPECIFICATION
MAS A/F SE-B1
●Engine: After warming up
●Air conditioner switch: OFF
●Shift lever: N
●No-loadIdle Approx. 1.0 - 1.5V
2,500 rpm Approx. 1.6 - 2.0V
CAL/LD VALUE
●Engine: After warming up
●Shift lever: N
●Air conditioner switch: OFF
●No-loadIdle 10% - 35%
2,500 rpm 10% - 35%
MASS AIRFLOW
●Engine: After warming up
●Shift lever: N
●Air conditioner switch: OFF
●No-loadIdle 1.0 - 4.0 g·m/s
2,500 rpm 4.0 - 10.0 g·m/s
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
72 OR Mass air flow sensor[Engine is running]
●Warm-up condition
●Idle speed1.1 - 1.5V
[Engine is running]
●Warm-up condition
●Engine speed is 2,500 rpm.1.6 - 2.0V
80 B/PMass air flow sensor
ground[Engine is running]
●Warm-up condition
●Idle speedApproximately 0V

DTC P0102, P0103 MAF SENSOR
EC-139
[QR25(WITH EURO-OBD)]
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EC
FAIL-SAFE MODE
When the malfunction is detected, the ECM enters fail-safe mode and the MI lights up.
DTC Confirmation ProcedureEBS00M2C
NOTE:
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 DTC P0102
With CONSULT-II
1. Turn ignition switch “ON”.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and wait at least 5 seconds.
4. If DTC is detected, go to EC-141, "
Diagnostic Procedure" .
With GST
Follow the procedure “With CONSULT-II” above.
PROCEDURE FOR DTC P0103
With CONSULT-II
1. Turn ignition switch “ON”.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Wait at least 5 seconds.
4. If DTC is detected, go to EC-141, "
Diagnostic Procedure" .
If DTC is not detected, go to next step.
5. Start engine and wait at least 5 seconds.
6. If DTC is detected, go to EC-141, "
Diagnostic Procedure" .
With GST
Follow the procedure “With CONSULT-II” above.
DTC No.Trouble diagnosis
nameDTC detecting condition Possible cause
P0102
0102Mass air flow sensor
circuit low inputAn excessively low voltage from the sensor is
sent to ECM.
●Harness or connectors
(The sensor circuit is open or shorted.)
●Intake air leaks
●Mass air flow sensor
P0103
0103Mass air flow sensor
circuit high inputAn excessively high voltage from the sensor is
sent to ECM.
●Harness or connectors
(The sensor circuit is open or shorted.)
●Mass air flow sensor
Detected items Engine operating condition in fail-safe mode
Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
SEF058Y
SEF058Y

EC-140
[QR25(WITH EURO-OBD)]
DTC P0102, P0103 MAF SENSOR
Wiring Diagram
EBS00M2D
TBWA0055E

DTC P0102, P0103 MAF SENSOR
EC-141
[QR25(WITH EURO-OBD)]
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Diagnostic ProcedureEBS00M2E
1.INSPECTION START
Which malfunction (P0102 or P0103) is duplicated?
P0102 or P0103
P0102 >> GO TO 2.
P0103 >> GO TO 3.
2.CHECK INTAKE SYSTEM
Check the following for connection.
●Air duct
●Vacuum hoses
●Intake air passage between air duct and intake manifold
OK or NG
OK >> GO TO 3.
NG >> Reconnect the parts.
3.RETIGHTEN GROUND SCREWS
1. Turn ignition switch “OFF”.
2. Loosen and retighten engine ground screws.
>> GO TO 4.
4.CHECK MAF SENSOR POWER SUPPLY CIRCUIT
1. Disconnect MAF sensor harness connector.
2. Turn ignition switch “ON”.
3. Check voltage between MAF sensor terminals 2, 4 and ground
with CONSULT-II or tester.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
PBIB0494E
PBIB0495E
Terminal Voltage
2 Approximately 5V
4 Battery voltage
PBIB0076E

EC-142
[QR25(WITH EURO-OBD)]
DTC P0102, P0103 MAF SENSOR
5. DETECT MALFUNCTIONING PART
Check the following.
●Harness for open or short between ECM relay and mass air flow sensor
●Harness for open or short between mass air flow sensor and ECM
>> Repair harness or connectors.
6. CHECK MAF SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch “OFF”.
2. Disconnect ECM harness connector.
3. Check harness continuity between MAF sensor terminal 3 and ECM terminal 80.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
7. CHECK MAF SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between MAF sensor terminal 1 and ECM terminal 72.
Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 8.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
8. CHECK MASS AIR FLOW SENSOR
Refer to EC-142, "
Component Inspection" .
OK or NG
OK >> GO TO 9.
NG >> Replace mass air flow sensor.
9. CHECK INTERMITTENT INCIDENT
Refer to EC-115, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionEBS00M2F
MASS AIR FLOW SENSOR
1. Reconnect harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.Continuity should exist.
Continuity should exist.