2003 NISSAN ALMERA N16 ecm

3 CHECK MAFS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch “OFF”.
2. Loosen and retighten engine ground screws.
SEF380Y
3. Check harness continuity between mass air flow sensor terminal 3 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK GO TO 5.
NG GO TO 4.
4 DETECT MALFUNCTIONING PART
Check harness for open or short between mass air flow sensor and ECM.
Repair open circuit or short to ground or short to power in harness or connectors.
5 CHECK MAFS INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between mass air flow sensor terminal 1 and ECMterminal 224. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OK GO TO 6.
NG Repair open circuit or short to ground or short to power in harness or connectors.
DTC P0100 MASS AIR FLOW SENYD
Diagnostic Procedure (Cont’d)
EC-82

6 CHECK 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 224 (Mass air flow sensor signal) andground.
SEF441Z
4. If the voltage is out of specification, disconnect MAFS harness connector and connect it again.
Then repeat above check.
OK or NG
OK GO TO 7.
NG Replace mass air flow sensor.
7 CHECK INTERMITTENT INCIDENT
Refer to “TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT”, EC-71.
INSPECTION END
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DTC P0100 MASS AIR FLOW SENYD
Diagnostic Procedure (Cont’d)
EC-83

SEF594K
DescriptionNJEC0649The engine coolant temperature sensor is used to detect the
engine coolant temperature. The sensor modifies a voltage signal
from the ECM. The modified signal returns to the ECM as the
engine coolant temperature input. The sensor uses a thermistor
which is sensitive to the change in temperature. The electrical
resistance of the thermistor decreases as temperature increases.
SEF012P

Engine coolant tempera-
ture °C (°F)Voltage* (V) Resistance (kΩ)
−10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.1 - 2.9
50 (122) 2.3 0.68 - 1.00
90 (194) 1.0 0.236 - 0.260
*: These data are reference values and measured between ECM terminal 347
(Engine coolant 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 terminals, such as
the ground.
On Board Diagnosis LogicNJEC0650This self-diagnosis has the one trip detection logic.
DTC Malfunction is detected when ... Check Items (Possible Cause)
P0115
0103An excessively high or low voltage from the sen-
sor is entered to ECM.Harness or connectors (The sensor circuit is
open or shorted.)
Engine coolant temperature sensor
SEF817Y
DTC Confirmation ProcedureNJEC0651WITH CONSULT-IINJEC0651S011) 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 “Diagnostic Procedure”, EC-87.
WITHOUT CONSULT-IINJEC0651S021) Turn ignition switch “ON” and wait at least 5 seconds.
2) Turn ignition switch “OFF”, wait at least 5 seconds and then
turn “ON”.
DTC P0115 COOLANT TEMP SENYD
Description
EC-84

3) Perform “Diagnostic Test Mode II (Self-diagnostic results)” with
ECM.
4) If DTC is detected, go to “Diagnostic Procedure”, EC-87.
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DTC P0115 COOLANT TEMP SENYD
DTC Confirmation Procedure (Cont’d)
EC-85

Diagnostic ProcedureNJEC0653
1 CHECK ECTS POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”.
2. Disconnect engine coolant temperature sensor harness connector.
SEF382Y
3. Turn ignition switch “ON”.
4. Check voltage between ECTS terminal 2 and ground with CONSULT-II or tester.
SEF401Y
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 ECTS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch “OFF”.
2. Check harness continuity between ECTS terminal 1 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OK GO TO 4.
NG GO TO 3.
3 DETECT MALFUNCTIONING PART
Check the following harness for open or short between ECM and engine coolant temperature sensor.
Repair open circuit or short to ground or short to power in harness or connectors.
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DTC P0115 COOLANT TEMP SENYD
Diagnostic Procedure
EC-87

DescriptionNJEC0679The accelerator work unit is installed on the upper end of the accelerator pedal assembly. The accelerator
position sensor and accelerator position switch are built into the accelerator work unit. The sensor detects the
accelerator position and sends a signal to the ECM. The ECM uses the signal to determine the amount of fuel
to be injected.
The accelerator position switch detects Off-accelerator switch signal and send these signals to the ECM. The
ECM will then determine engine idle conditions. These signals are also used for diagnosing the accelerator
position sensor.
SEF885Y
CONSULT-II Reference Value in Data Monitor
Mode
NJEC0680Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
ACCEL POS SENIgnition switch: ON
(Engine stopped)Accelerator pedal: released 0.30 - 0.50V
Accelerator pedal: depressed 3.0 - 4.3V
OFF ACCEL SWIgnition switch: ON
(Engine stopped)Accelerator pedal: fully released ON
Accelerator pedal: slightly open OFF
ECM Terminals and Reference ValueNJEC0681Specification 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.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA(DC Voltage)
425 P/BAccelerator position sensor
ground[Engine is running]
Warm-up condition
Idle speedApproximately 0V
426 BR/RAccelerator position switch
(Idle) ground[Ignition switch “ON”]Approximately 0V
433 G/YAccelerator position sensor
power supply[Ignition switch “ON”]Approximately 5V
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DTC P0120 ACCEL POS SENSORYD
Description
EC-89

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA(DC Voltage)
434 W Accelerator position sensor[Ignition switch “ON”]
Accelerator pedal fully released0.30 - 0.50V
[Ignition switch “ON”]
Accelerator pedal fully depressed3.0 - 4.3V
435 W/GAccelerator position switch
(Idle)[Ignition switch “ON”]
Accelerator pedal fully releasedApproximately 0V
[Ignition switch “ON”]
Accelerator pedal depressedBATTERY VOLTAGE
(11 - 14V)
On Board Diagnosis LogicNJEC0682This self-diagnosis has the one trip detection logic.
DTC Malfunction is detected when ... Check Items (Possible Cause)
P0120
0403The relation between sensor and switch signals
is not in the nomal range during the specified
accelerator positions.Harness or connectors
(The sensor circuit is open or shorted.)
Accelerator position sensor
Accelerator position switch
SEF817Y
DTC Confirmation ProcedureNJEC0683WITH CONSULT-IINJEC0683S011) Turn ignition switch “ON”.
2) Select “DATA MONITOR” mode with CONSULT-II.
3) Depress and release fully accelerator pedal slowly.
4) If DTC is detected, go to “Diagnostic Procedure”, EC-92.
WITHOUT CONSULT-IINJEC0683S021) Turn ignition switch “ON”.
2) Depress and release fully accelerator pedal slowly.
3) Turn ignition switch “OFF”, wait at least 5 seconds and then
turn “ON”.
4) Perform “Diagnostic Test Mode II (Self-diagnostic results)” with
ECM.
5) If DTC is detected, go to “Diagnostic Procedure”, EC-92.
DTC P0120 ACCEL POS SENSORYD
ECM Terminals and Reference Value (Cont’d)
EC-90

Diagnostic ProcedureNJEC0685
1 CHECK ACCELERATOR POSITION SENSOR FUNCTION
With CONSULT-II
1. Turn ignition switch “ON”.
2. Select “ACCEL POS SEN” in “DATA MONITOR” mode with CONSULT-II.
3. Check “ACCEL POS SEN” signal under the following conditions.
SEF436Z
Without CONSULT-II
1. Turn ignition switch “ON”.
2. Check voltage between ECM terminal 434 and ground under the following conditions.
SEF437Z
OK or NG
OK GO TO 2.
NG GO TO 3.
DTC P0120 ACCEL POS SENSORYD
Diagnostic Procedure
EC-92