1998 NISSAN PATROL heat

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CHECK OUTPUT SIGNAL CIRCUIT.
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM
terminal
V14and terminalV1.
Continuity should exist.
If OK, check harness for short to ground
and short to power.
OK
cNG
Check the following.
+Harness connectors
E127,M21
+Harness connectors
M52,F7
+Harness for open or short
between cooling fan
relay-1 and ECM
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
CHECK COMPONENT
(Cooling fan relay-1).
Refer to ``COMPONENT INSPECTION'',
EC-121.
OK
cNG
Replace cooling fan relay.
CHECK COMPONENT
(Cooling fan motor-1).
Refer to ``COMPONENT INSPECTION'',
EC-121.
OK
cNG
Replace cooling fan motor.
Disconnect and reconnect harness connec-
tors in the circuit. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage and
check the connection of ECM harness con-
nector. Reconnect ECM harness connector
and retest.
INSPECTION END
SEF760V
SEF761V
SEF762V
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``OVER HEAT'' (DTC 28)
Cooling Fan (Overheat) (Cont'd)
EC-118

CHECK COOLING SYSTEM FOR LEAK.
Apply pressure to the cooling system with
a tester, and check if the pressure drops.
Testing pressure:
157 kPa (1.57 bar, 1.6 kg/cm
2, 23 psi)
Pressure should not drop.
CAUTION:
Higher than the speci®ed pressure may
cause radiator damage.
OK
cNG
Check the following for
leak.
+Hose
+Radiator
+Water pump
Refer to LC section (``Water
Pump'').
CHECK RADIATOR CAP.
Apply pressure to cap with a tester.
Radiator cap relief pressure:
78 - 98 kPa (0.78 - 0.98 bar, 0.8 - 1.0
kg/cm
2, 11 - 14 psi)
OK
cNG
Replace radiator cap.
CHECK THERMOSTAT.
1. Check valve seating condition at normal
room temperatures.
It should seat tightly.
2. Check valve opening temperature and
valve lift.
Valve opening temperature:
82ÉC (180ÉF) [standard]
Maximum valve lift:
More than 10 mm/95ÉC
(0.39 in/203ÉF)
3. Check if valve is closed at 5ÉC (9ÉF)
below valve opening temperature.
For details, refer to LC section (``Thermo-
stat'').
OK
cNG
Replace thermostat.
Check engine coolant temperature sensor.
Refer to ``COMPONENT INSPECTION'',
EC-82.
OK
cNG
Replace engine coolant
temperature sensor.
If the cause cannot be isolated, go to
``MAIN 12 CAUSES OF OVERHEATING''
on next page.
INSPECTION END
Perform FINAL CHECK by the following procedure after repair
is completed.
1. Warm up engine. Run the vehicle for at least 20 minutes. Pay
attention to engine coolant temperature gauge on the instrument
panel. If the reading shows an abnormally high temperature,
another part may be malfunctioning.
2. Stop vehicle and let engine idle. Check the intake and exhaust
systems for leaks by listening for noise or visually inspecting the
components.
3. Allow engine to cool and visually check for oil and coolant leaks.
Then, perform ``OVERALL FUNCTION CHECK''.
SLC754AA
SLC755AB
SLC343
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``OVER HEAT'' (DTC 28)
Cooling Fan (Overheat) (Cont'd)
EC-119

MAIN 12 CAUSES OF OVERHEATING
Engine Step Inspection item Equipment Condition Reference page
OFF 1+Blocked radiator
+Blocked radiator grille
+Blocked bumper+Visual No blocking Ð
2+Coolant mixture+Coolant tester 50 - 50% coolant mixture See ``RECOMMENDED
FLUIDS AND LUBRI-
CANTS'' in MA section.
3+Coolant level+Visual Coolant up to MAX level
in reservoir tank and
radiator ®ller neckSee ``Changing Engine
Coolant'', ``ENGINE
MAINTENANCE'' in MA
section.
4+Radiator cap+Pressure tester 78 - 98 kPa
(0.78 - 0.98 bar, 0.8 - 1.0
kg/cm
2, 11 - 14 psi)See ``System Check''
``ENGINE COOLING
SYSTEM'' in LC section.
ON*
25+Coolant leaks+Visual No leaks See ``System Check''
``ENGINE COOLING
SYSTEM'' in LC section.
ON*
26+Thermostat+Touch the upper and
lower radiator hosesBoth hoses should be hot See ``Thermostat'' and
``Radiator'', ``ENGINE
COOLING SYSTEM'' in
LC section.
ON*
17+Cooling fan+CONSULT Operating See ``TROUBLE DIAG-
NOSIS FOR DTC 28'',
EC-113.
OFF 8+Combustion gas leak+Color checker chemical
tester 4 Gas analyzerNegative Ð
ON*
39+Coolant temperature
gauge+Visual Gauge less than 3/4
when drivingÐ
+Coolant over¯ow to res-
ervoir tank+Visual No over¯ow during driving
and idlingSee ``Changing Engine
Coolant'', ``ENGINE
MAINTENANCE'' in MA
section.
OFF*
410+Coolant return from res-
ervoir tank to radiator+Visual Should be initial level in
reservoir tankSee ``ENGINE MAINTE-
NANCE'' in MA section.
OFF 11+Cylinder head+Straight gauge feeler
gauge0.1mm (0.004 in) Maxi-
mum distortion (warping)See ``Inspection'', ``CYL-
INDER HEAD'' in EM
section.
12+Cylinder block and pis-
tons+Visual No scuffing on cylinder
walls or pistonSee ``Inspection'', ``CYL-
INDER BLOCK'' in EM
section.
*1: Turn the ignition switch ON.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
For more information, refer to ``OVERHEATING CAUSE ANALYSIS'' in LC section.
TROUBLE DIAGNOSIS FOR ``OVER HEAT'' (DTC 28)
Cooling Fan (Overheat) (Cont'd)
EC-120

COMPONENT INSPECTION
Cooling fan relay-1
Check continuity between terminalsV3andV5.
Conditions Continuity
12V direct current supply between
terminals
V1andV2Ye s
No current supply No
If NG, replace relay.
Cooling fan motor-1
1. Disconnect cooling fan motor harness connector.
2. Supply cooling fan motor terminals with battery voltage and
check operation.
Terminals
(Å)(@)
Cooling fan motor
V1,V3V2,V4
Cooling fan motor should operate.
If NG, replace cooling fan motor.
SEF511P
SEF763V
TROUBLE DIAGNOSIS FOR ``OVER HEAT'' (DTC 28)
Cooling Fan (Overheat) (Cont'd)
EC-121

Glow Control System
SYSTEM DESCRIPTION
Crankshaft position sensor (TDC)cEngine speed
ECMcGlow relaycGlow plugs
Engine coolant temperature sensorcEngine coolant temperaturecGlow lamp
When engine coolant temperature is more than 90ÉC (194ÉF), the glow relay turns off, inactivating the quick-
glow control until coolant temperature drops below 70ÉC (158ÉF).
When coolant temperature is lower than 90ÉC (194ÉF):
+Ignition switch ON
After ignition switch has turned to ON, the glow relay turns ON for a certain period of time in relation to
engine coolant temperature, allowing current to ¯ow through glow plug.
+Cranking
The glow relay turns ON, allowing current to ¯ow through glow plug.
+Starting
After engine has started, current continues to ¯ow through glow plug (after-glow mode) for a certain period
in relation to engine coolant temperature.
When engine speed exceeds 2,400 rpm, current ¯ow through glow plug is interrupted.
The glow lamp turns ON for a certain period of time in relation to engine coolant temperature at the time glow
relay is turned ON.
COMPONENT DESCRIPTION
Glow plug
The glow plug is provided with a ceramic heating element to obtain
a high-temperature resistance. It glows in response to a signal sent
from the ECM, allowing current to ¯ow through the glow plug via the
glow relay.
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)
16 L/W Glow lampIgnition switch ``ON''
Glow lamp is ``ON''.0 - 1.5V
Ignition switch ``ON''
Glow lamp is ``OFF''.BATTERY VOLTAGE
(11 - 14V)
111 LG/B Glow relay Refer to ``SYSTEM DESCRIPTION''.
SEF857S
TROUBLE DIAGNOSES FOR NON-DETECTABLE ITEMS
EC-151

3. After-glow system
a. Connect ``S'' terminal to starter motor.
b. Start engine and read voltage.
Voltage:
Battery voltage for 5* minutes
* Engine coolant temperature is lower than 50ÉC
(122ÉF).
COMPONENT INSPECTION
Glow relay
1. Check relay for coil continuity.
Continuity should exist.
2. Check relay for proper operation.
Coil voltage Continuity Contact point
0V No OFF
12V Yes ON
Glow plug
1. Remove glow plug connecting plate.
2. Check each glow plug for continuity.
Continuity should exist:
Approximately 0.8W[at 25ÉC (77ÉF)]
+If NG, replace glow plug.
3. Install glow plug connecting plate securely.
+Do not bump glow plug heating element. If it is bumped,
replace glow plug with new one. (If glow plug is dropped
from a height of 10 cm (3.94 in), replace with new one.)
+If glow plug installation hole is contaminated with carbon,
remove using a reamer or suitable tool.
+Hand-tighten glow plug by turning it two to three times,
then tighten using a tool to speci®ed torque.
:15-20Nzm (1.5 - 2.0 kg-m, 11 - 14 ft-lb)
SEF781V
SEC564B
SEF701V
SEC565B
TROUBLE DIAGNOSES FOR NON-DETECTABLE ITEMS
Glow Control System (Cont'd)
EC-155

Heat Up Switch
The heat up switch is located on the lower side of the instrument
panel. This switch is used to speed up the heater's operation when
the engine is cold.
When the ECM received the heat up switch ``ON'' signal, the ECM
increases the engine idle speed to 1,100 - 1,200 rpm to warm up
engine quickly.
This system works when all conditions listed below are met.
Heat up switch ON
Engine coolant temperature Below 70ÉC (158ÉF)
Shift lever ``P'' or ``N''
Accelerator pedal Fully released
Vehicle speed Below 4 km/h (2 MPH)
CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Speci®cation data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
WARM UP SW+Ignition switch: ONHeat up switch: ON ON
Heat up switch: OFF OFF
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)
59 BR/W Heat up switchIgnition switch ``ON''
Heat up switch is ``OFF''.0V
Ignition switch ``ON''
Heat up switch is ``ON''.BATTERY VOLTAGE
(11 - 14V)
SEF803V
TROUBLE DIAGNOSES FOR NON-DETECTABLE ITEMS
EC-183

TEC447
TROUBLE DIAGNOSES FOR NON-DETECTABLE ITEMS
Heat Up Switch (Cont'd)
EC-184