2003 NISSAN ALMERA N16 flow

EC-128
[QG (WITH EURO-OBD)]
DTC P0037, P0038 HO2S2 HEATER
DTC P0037, P0038 HO2S2 HEATER
PFP:226A0
DescriptionEBS00K4P
SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the heated oxygen sensor 2 heater corresponding to the engine speed,
amount of intake air and engine coolant temperature.
OPERATION
CONSULT-II Reference Value in Data Monitor ModeEBS00K4Q
Specification data are reference values.
On Board Diagnosis LogicEBS00K4R
DTC Confirmation ProcedureEBS00K4S
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.
Sensor Input Signal to ECM ECM Function Actuator
Camshaft position sensor (PHASE)
Engine speed
Heated oxygen sensor 2
heater controlHeated oxygen sensor 2 heater Crankshaft position sensor (POS)
Engine coolant temperature sensorEngine coolant tempera-
ture
Mass air flow sensor Amount of intake air
Engine speed rpm Heated oxygen sensor 2 heater
Above 3,800 OFF
●Below 3,800 rpm after the following conditions are met.
●Engine: After warming up
●Keeping the engine speed between 3,500 and 4,000 rpm for
one minute and at idle for one minute under no loadON
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 HTR (B1)
●Engine speed: Below 3,800 rpm after the following conditions are met.
●Engine: After warming up
●Keeping the engine speed between 3,500 and 4,000 rpm for one minute
and at idle for one minute under no loadON
●Engine speed: Above 3,800 rpm OFF
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0037
0037Heated oxygen sensor 2
heater control circuit lowThe current amperage in the heated oxygen sensor
2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)
●Harness or connectors
(The heated oxygen sensor 2 heater
circuit is open or shorted.)
●Heater oxygen sensor 2 heater
P0038
0038Heated oxygen sensor 2
heater control circuit highThe current amperage in the heated oxygen sensor
2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)
●Harness or connectors
(The heated oxygen sensor 2 heater
circuit is shorted.)
●Heater oxygen sensor 2 heater

EC-134
[QG (WITH EURO-OBD)]
DTC P0102, P0103 MAF SENSOR
DTC P0102, P0103 MAF SENSOR
PFP:22680
Component DescriptionEBS00K4X
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 ModeEBS00K4Y
Specification data are reference values.
On Board Diagnosis LogicEBS00K4Z
These self-diagnoses have the one trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, the ECM enters fail-safe mode and the MI lights up.
SEC266C
MONITOR ITEM CONDITION SPECIFICATION
MAS A/F SE-B1
●Engine: After warming up
●Air conditioner switch: OFF
●Shift lever:
N (A/T models)
Neutral (M/T models)
●No-loadIdle Approx. 1.0 - 1.7V
2,500 rpm Approx. 1.5 - 2.1V
CAL/LD VALUE
●Engine: After warming up
●Shift lever:
N (A/T models)
Neutral (M/T models)
●Air conditioner switch: OFF
●No-loadIdle 10% - 35%
2,500 rpm 10% - 35%
MASS AIRFLOW
●Engine: After warming up
●Shift lever:
N (A/T models)
Neutral (M/T models)
●Air conditioner switch: OFF
●No-loadIdle 1.0 - 4.0 g·m/s
2,500 rpm 5.0 - 10.0 g·m/s
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0102
0102Mass air flow sensor circuit
low inputAn excessively low voltage from the sensor
is sent to ECM when engine is running.
●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.

DTC P0102, P0103 MAF SENSOR
EC-137
[QG (WITH EURO-OBD)]
C
D
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H
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K
L
MA
EC
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.
Diagnostic ProcedureEBS00K52
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 to 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.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
45 RSensor power supply
(Mass air flow sensor)[Ignition switch “ON”]Approximately 5V
50 Y Mass air flow sensor[Engine is running]
●Warm-up condition
●Idle speed1.0 - 1.7V
[Engine is running]
●Warm-up condition
●Engine speed is 2,500 rpm.1.5 - 2.1V
67 BSensor ground
(Mass air flow sensor)[Engine is running]
●Warm-up condition
●Idle speedApproximately 0V
MBIB0095E

EC-138
[QG (WITH EURO-OBD)]
DTC P0102, P0103 MAF SENSOR
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.
5. DETECT MALFUNCTIONING PART
Check the following.
●Harness connectors E225, F43
●Harness for open or short between mass air flow sensor and ECM
●Harness for open or short between mass air flow sensor and ECM relay
>> Repair open circuit or short to ground or short to power in 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 67.
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.
MBIB0096E
Terminal Voltage
2 Approximately 5V
4 Battery voltage
PBIB0076E
Continuity should exist.

DTC P0102, P0103 MAF SENSOR
EC-139
[QG (WITH EURO-OBD)]
C
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EC
7.CHECK MAF SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between MAF sensor terminal 1 and ECM terminal 50.
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-139, "
Component Inspection" .
OK or NG
OK >> GO TO 9.
NG >> Replace mass air flow sensor.
9.CHECK INTERMITTENT INCIDENT
Refer to EC-109, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionEBS00K53
MASS AIR FLOW SENSOR
1. Reconnect harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal 50 (Mass air flow sensor
signal) and ground.
*: Check for liner voltage rise in response to engine being increased to about
4,000 rpm.
4. If the voltage is out of specification, proceed the following.
a. Turn ignition switch “OFF”.
b. Disconnect mass air flow sensor harness connector and reconnect it again.
c. Perform steps 2 and 3 again.
5. If NG, remove mass air flow sensor from air duct. Check hot film for damage or dust.
6. If NG, clean or replace mass air flow sensor.
Removal and InstallationEBS00K54
MASS AIR FLOW SENSOR
Refer to EM-14, "AIR CLEANER AND AIR DUCT" . Continuity should exist.
Condition Voltage V
Ignition switch “ON” (Engine stopped.) Approx. 1.0
Idle (Engine is warmed-up to normal operating
temperature.)1.0 - 1.7
2,500 rpm (Engine is warmed-up to normal
operating temperature.)1.5 - 2.1
Idle to about 4,000 rpm* 1.0 - 1.7 to Approx. 4.0
MBIB0017E

EC-140
[QG (WITH EURO-OBD)]
DTC P0112, P0113 IAT SENSOR
DTC P0112, P0113 IAT SENSOR
PFP:22630
Component DescriptionEBS00K55
The intake air temperature sensor is built into mass air flow sensor.
The sensor detects intake air temperature and transmits a signal to
the ECM.
The temperature sensing unit uses a thermistor which is sensitive to
the change in temperature. Electrical resistance of the thermistor
decreases in response to the temperature rise.

*: These data are reference values and are measured between ECM terminal 34
(Intake air temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output
voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM termi-
nals, such as the ground.
On Board Diagnosis LogicEBS00K56
DTC Confirmation ProcedureEBS00K57
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.
WITH CONSULT-II
1. Turn ignition switch “ON”.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Wait at least 5 seconds.
4. If 1st trip DTC is detected, go to EC-142, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
SEC266C
Intake air
temperature°C (°F)Vo lta g e * V R e s i s ta n c e kΩ
−10 (14) 4.43 7.9 - 9.3
25 (77) 3.32 1.9 - 2.1
80 (176) 1.23 0.31 - 0.37
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0112
0112Intake air temperature
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 temperature sensor P0113
0113Intake air temperature
sensor circuit high inputAn excessively high voltage from the sensor is
sent to ECM.
SEF058Y

EC-142
[QG (WITH EURO-OBD)]
DTC P0112, P0113 IAT SENSOR
Diagnostic Procedure
EBS00K59
1. CHECK INTAKE AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”.
2. Disconnect mass air flow sensor (intake air temperature sensor
is built-into) harness connector.
3. Turn ignition switch “ON”.
4. Check voltage between MAF sensor terminal 5 and ground.
OK or NG
OK >> GO TO 2.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
2. CHECK INTAKE AIR TEMPERATURE 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 67.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
3. CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to EC-143, "
Component Inspection" .
OK or NG
OK >> GO TO 4.
NG >> Replace mass air flow sensor (with intake air temperature sensor).
4. CHECK INTERMITTENT INCIDENT
Refer to EC-109, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
MBIB0096E
Voltage: Approximately 5V
PBIB0066E
Continuity should exist.

DTC P0112, P0113 IAT SENSOR
EC-143
[QG (WITH EURO-OBD)]
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EC
Component InspectionEBS00K5A
INTAKE AIR TEMPERATURE SENSOR
1. Check resistance between mass air flow sensor terminals 3 and
5 under the following conditions.
2. If NG, replace mass air flow sensor (with intake air temperature
sensor).
Removal and InstallationEBS00K5B
MASS AIR FLOW SENSOR
Refer to EM-14, "AIR CLEANER AND AIR DUCT" .
Intake air temperature °C (°F) Resistance kΩ
25 (77) 1.9 - 2.1
SEC266C
SEF012P