engine NISSAN PATROL 2000 Electronic Repair Manual

Main Power Supply and Ground Circuit
ECM TERMINALS AND REFERENCE VALUE
Remarks: 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 damage the
ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
4 B/Y ECM relay (Self-shutoff)Ignition switch ªONº
Ignition switch ªOFFº
For a few seconds after turning ignition switch
ªOFFºApproximately 0.25V
Ignition switch ªOFFº
A few seconds passed after turning ignition
switch ªOFFºBATTERY VOLTAGE
(11 - 14V)
38 B/Y Ignition switchIgnition switch ªOFFº
0V
Ignition switch ªONº
BATTERY VOLTAGE
(11 - 14V)
39
43B
BECM groundEngine is running.
Idle speedApproximately 0V
56
61
116W
W
WPower supply for ECM Ignition switch ªONº
BATTERY VOLTAGE
(11 - 14V)
102 G/R Current returnEngine is running.
Idle speedBATTERY VOLTAGE
(11 - 14V)
106
112
118B
B
BECM groundEngine is running.
Idle speedApproximately 0V
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
EC-1077

DIAGNOSTIC PROCEDURE
1 INSPECTION START
Start engine.
Is engine running?
Yes or No
YescGO TO 14.
NocGO TO 2.
2 CHECK ECM POWER SUPPLY CIRCUIT-I
1. Turn ignition switch ªONº.
2. Check voltage between ECM terminal 38 and ground with CONSULT-II or tester.
SEF397Y
OK or NG
OKcGO TO 4.
NGcGO TO 3.
3 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors M51, F6
+Fuse block (J/B) connector M2
+10A fuse
+Harness for open or short between ECM and fuse
cRepair open circuit or short to ground or short to power in harness or connectors.
4 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals 39, 43, 106, 112, 118 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
OKcGO TO 6.
NGcGO TO 5.
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)
EC-1080

5 DETECT MALFUNCTIONING PART
Check the following.
+Joint connector-3
+Harness for open or short between ECM and engine ground
cRepair open circuit or short to ground or short to power in harness or connectors.
6 CHECK ECM POWER SUPPLY CIRCUIT-II
1. Reconnect ECM harness connector.
2. Turn ignition switch ªONº and then ªOFFº.
3. Check voltage between ECM terminals 56, 61, 116 and ground with CONSULT-II or tester.
SEF288Z
OK or NG
OKcCheck electronic control fuel injection pump power supply circuit. Refer to ªDiagnostic
Procedureº, EC-1169.
NG (Battery voltage does not
exist.)cGO TO 7.
NG (Battery voltage exists for
more than a few seconds.)cGO TO 13.
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)
EC-1081

17 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors M50, F5
+Harness for open or short between ECM and ECM relay
cRepair open circuit or short to ground or short to power in harness or connectors.
18 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminals 39, 43, 106, 112, 118 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
2. Also check harness for short to ground and short to power.
OK or NG
OKcGO TO 20.
NGcGO TO 19.
19 DETECT MALFUNCTIONING PART
Check the following.
+Joint connector-3
+Harness for open or short between ECM and engine ground
cRepair open circuit or short to ground or short to power in harness or connectors.
20 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-1076.
cINSPECTION END
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)
EC-1085

Component Description
The mass air flow sensor (MAFS) is placed in the stream of
intake air. It measures the intake air flow rate by measuring a
part of the entire intake air flow. It consists of a hot wire that is
supplied with electric current from the ECM. The temperature of
the hot wire is controlled by the ECM a certain amount. The heat
generated by the hot wire 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 main-
tain the temperature of the hot wire as air flow increases. The
ECM detects the air flow by means of this current change.
CONSULT-II Reference Value in Data Monitor
Mode
Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
MAS AIR/FL SE+Engine: After warming up
+Air conditioner switch: ªOFFº
+Shift lever: Neutral position
+No-loadIdle 1.6 - 2.0V
ECM Terminals and Reference Value
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 damage the
ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
35 R Mass air flow sensorEngine is running.
Warm-up condition
Idle speed1.6 - 2.0V
49 W Sensor's power supply Ignition switch ªONº
Approximately 5V
50 B Sensor's groundEngine is running.
Warm-up condition
Idle speedApproximately 0V
On Board Diagnosis Logic
Malfunction is detected when ... Check Items (Possible Cause)
+An excessively high or low voltage from the sensor is sent to
ECM.+Harness or connectors
(The sensor circuit is open or shorted.)
+Mass air flow sensor
SEF987W
DTC 0102 MASS AIR FLOW SENZD30DDTi
EC-1086

DTC Confirmation Procedure
WITH CONSULT-II
1) Turn ignition switch ªONº, and wait at least 6 seconds.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and wait at least 3 seconds.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-1089.
WITHOUT CONSULT-II
1) Turn ignition switch ªONº, and wait at least 6 seconds.
2) Start engine and wait at least 3 seconds.
3) Turn ignition switch ªOFFº, wait at least 5 seconds and then
turn ªONº.
4) Perform ªDiagnostic Test Mode II (Self-diagnostic results)º
with ECM.
5) If DTC is detected, go to ªDiagnostic Procedureº, EC-1089.
SEF817Y
DTC 0102 MASS AIR FLOW SENZD30DDTi
EC-1087

3 CHECK MAFS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
SEF227Z
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
OKcGO TO 5.
NGcGO TO 4.
4 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E230, F12
+Harness connectors M51, F6
+Harness connectors E106, M88
+Harness for open or short between mass air flow sensor and ECM
+Harness for open or short between mass air flow sensor and TCM (Transmission control module)
cRepair 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 ECM terminal 35. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OKcGO TO 7.
NGcGO TO 6.
6 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E230, F12
+Harness for open or short between mass air flow sensor and ECM
cRepair open circuit or short to ground or short to power in harness or connectors.
DTC 0102 MASS AIR FLOW SENZD30DDTi
Diagnostic Procedure (Cont'd)
EC-1090

7 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 35 (Mass air flow sensor signal) and ground.
SEF400Y
4. If the voltage is out of specification, disconnect MAFS harness connector and connect it again.
Then repeat above check.
OK or NG
OKcGO TO 8.
NGcReplace mass air flow sensor.
8 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-1076.
cINSPECTION END
DTC 0102 MASS AIR FLOW SENZD30DDTi
Diagnostic Procedure (Cont'd)
EC-1091

Description
The engine coolant temperature sensor is used to detect the
engine coolant temperature. The sensor modifies a voltage sig-
nal 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.

Engine coolant tempera-
ture ÉC (ÉF)Voltage* (V) Resistance (kW)
þ10 (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 19
(Engine coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/
output voltage. Doing so may damage the ECM's transistor.
Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis Logic
Malfunction is detected when ... Check Items (Possible Cause)
+An excessively high or low voltage from the sensor is entered
to ECM.+Harness or connectors (The sensor circuit is open or shorted.)
+Engine coolant temperature sensor
DTC Confirmation Procedure
WITH CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 5 seconds.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-1094.
WITHOUT CONSULT-II
1) Turn ignition switch ªONº and wait at least 5 seconds.
2) Turn ignition switch ªOFFº, wait at least 5 seconds and then
turn ªONº.
3) Perform ªDiagnostic Test Mode II (Self-diagnostic results)º
with ECM.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-1094.
SEF594K
SEF012P
SEF817Y
DTC 0103 COOLANT TEMP SENZD30DDTi
EC-1092

Diagnostic Procedure
1 CHECK ECTS POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect engine coolant temperature sensor harness connector.
SEF228Z
3. Turn ignition switch ªONº.
4. Check voltage between ECTS terminal 2 and ground with CONSULT-II or tester.
SEF401Y
OK or NG
OKcGO TO 3.
NGcGO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E230, F12
+Harness for open or short between engine control temperature sensor and ECM
cRepair open circuit or short to ground or short to power in harness or connectors.
3 CHECK ECTS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
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
OKcGO TO 5.
NGcGO TO 4.
DTC 0103 COOLANT TEMP SENZD30DDTi
EC-1094