1998 NISSAN PATROL Engine Control Workshop Manual

Engine Coolant Temperature (ECT) Sensor
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modi®es a voltage signal from the
ECM. The modi®ed signal returns to the ECM as the engine cool-
ant temperature input. The sensor uses a thermistor which is sen-
sitive 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
V19(Engine coolant temperature sensor) and ECM terminalV43(ECCS ground).
Diagnostic
Trouble Code
No.Malfunction is detected when ...Check Items
(Possible Cause)
13+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
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
1) Turn ignition switch ``ON''.
2) Select ``DATA MONITOR'' mode with CONSULT.
3) Wait at least 5 seconds.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Turn ignition switch ``ON'' and wait at least 5 seconds.
2) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
3) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
SEF594K
SEF012P
SEF741V
TROUBLE DIAGNOSIS FOR ``COOLANT TEMP SEN'' (DTC 13)
EC-79

TEC425
TROUBLE DIAGNOSIS FOR ``COOLANT TEMP SEN'' (DTC 13)
Engine Coolant Temperature (ECT) Sensor
(Cont'd)
EC-80

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY.
1. Turn ignition switch ``OFF''.
2. Disconnect engine coolant temperature
sensor harness connector.
3. Turn ignition switch ``ON''.
4. Check voltage between terminal
V2and ground with CONSULT or tester.
Voltage:
Approximately 5V
OK
cNG
Check the following.
+Harness connectors
E202,E69+Harness connectorsE127,M21+Harness connectorsM51,F6+Harness for open or
short between ECM and
engine coolant tempera-
ture sensor
If NG, repair harness or
connectors.
CHECK GROUND CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Check harness continuity between ter-
minal
V1and engine ground.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
+Harness connectors
E202,E69+Harness connectorsE127,M21+Harness connectorsM50,F5+Harness connectorsF6,M51+Harness connectorsM88,E106+Harness for open or
short between ECM and
engine coolant tempera-
ture sensor
+Harness for open or
short between TCM and
engine coolant tempera-
ture sensor
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
CHECK COMPONENT
(Engine coolant temperature sensor).
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace engine coolant
temperature sensor.
Disconnect and reconnect harness con-
nectors in the circuit. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage and
check the connection of ECM harness
connector. Reconnect ECM harness con-
nector and retest.
INSPECTION END
SEF678V
SEF541P
SEF542P
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``COOLANT TEMP SEN'' (DTC 13)
Engine Coolant Temperature (ECT) Sensor
(Cont'd)
EC-81

COMPONENT INSPECTION
Engine coolant temperature sensor
Check resistance as shown in the ®gure.
Temperature ÉC (ÉF) Resistance kW
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.0
90 (194) 0.236 - 0.260
If NG, replace engine coolant temperature sensor.
SEF152P
SEF012P
TROUBLE DIAGNOSIS FOR ``COOLANT TEMP SEN'' (DTC 13)
Engine Coolant Temperature (ECT) Sensor
(Cont'd)
EC-82

Vehicle Speed Sensor (VSS)
The vehicle speed sensor is installed in the transaxle. It contains a
pulse generator which provides a vehicle speed signal to the
speedometer. The speedometer then sends a signal to the ECM.
ECM TERMINALS AND REFERENCE VALUE
Remarks: Speci®cation data are reference values and are measured between each terminal andV43(ECCS
ground) with a voltmeter.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC Voltage and Pulse
Signal)
26 L/OR Vehicle speed sensorEngine is running.
Lift up the vehicle.In 1st gear positionVehicle speed is 40 km/h (25 MPH).0 - BATTERY VOLTAGE
(11 - 14V)
SEF717V
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.Malfunction is detected when ....Check Items
(Possible Cause)
14+The almost 0 km/h (0 MPH) signal from vehicle speed
sensor is sent to ECM even when vehicle is being
driven.+Harness or connector
(The vehicle speed sensor circuit is open or shorted.)
+Vehicle speed sensor
AEC110
TROUBLE DIAGNOSIS FOR ``VEHICLE SPEED SEN'' (DTC 14)
EC-83

OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the vehicle
speed sensor circuit. During this check, a DTC might not be con-
®rmed.
1) Jack up drive wheels.
2) Start engine.
3) Read vehicle speed sensor signal in ``DATA MONITOR''
mode with CONSULT.
The vehicle speed on CONSULT should be able to
exceed 10 km/h (6 MPH) when rotating wheels with suit-
able gear position.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Jack up drive wheels.
2) Start engine.
3) Rotate drive wheel by hand.
4) Check voltage between ECM terminal
V26and ground
with tester.
Voltage should vary between 0V - battery voltage.
SEF941N
SEF811R
TROUBLE DIAGNOSIS FOR ``VEHICLE SPEED SEN'' (DTC 14)
Vehicle Speed Sensor (VSS) (Cont'd)
EC-84

TEC426
TROUBLE DIAGNOSIS FOR ``VEHICLE SPEED SEN'' (DTC 14)
Vehicle Speed Sensor (VSS) (Cont'd)
EC-85

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK INPUT SIGNAL CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect ECM harness connector
and combination meter harness con-
nector.
3. Check harness continuity between ECM
terminal
V26and meter terminalV26.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
+Harness connectors
M52,F7
+Joint connectorM79
+Harness for open or
short between ECM and
combination meter
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
CHECK SPEEDOMETER FUNCTION.
Make sure that speedometer functions
properly.
OK
cNG
Check the following.
+Harness connectors
M86,E104(LHD mod-
els)
+Harness connectors
M21,E127(RHD mod-
els)
+Harness connectors
E70,E201
+Harness for open or
short between combina-
tion meter and vehicle
speed sensor
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
Check vehicle speed sen-
sor and its circuit.
Refer to EL section.
Disconnect and reconnect harness con-
nectors in the circuit. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage and
check the connection of ECM harness
connector. Reconnect ECM harness con-
nector and retest.
INSPECTION END
SEF742V
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``VEHICLE SPEED SEN'' (DTC 14)
Vehicle Speed Sensor (VSS) (Cont'd)
EC-86