NISSAN PICK-UP 1998 Repair Manual

ENGINE COOLANT TEMPERATURE SENSOR
Disconnect engine coolant temperature harness connector and
measure resistance.
Coolant temp. ÉC (ÉF) Resistance kW
þ25 (þ13) 19
0 (32) 5.6
20 (68) 2.5
40 (104) 1.2
DEF020
QUICK-GLOW SYSTEMTD
Component Inspection (Cont'd)
EC-209

Component Parts Location
DEC024
EGR SYSTEMTD
EC-210

Description
The EGR system is designed to control the formation of NOx emission by recirculating the exhaust gas into
the intake manifold passage through the EGR valve.
For electrical circuit of the EGR system, refer to ``Circuit Diagram'' in ``QUICK-GLOW SYSTEM'', EC-195.
DEC025
EGR SYSTEMTD
EC-211

Operation
Coolant
temperature
ÉC (ÉF)Engine load
(EGR area)EGRC-solenoid valve
EGR valveThrottle chamber
control valveAmount of EGR
gas
AB
Below 60 (140) All OFF (Closed) OFF (Closed) Closed Open Ð
Above 60 (140)Low load
(Area
V1)ON (Open) ON (Open) Open Nearly closed High
Middle load
(Area
V2)OFF (Closed) ON (Open) Open Open Low
High load*1
(Area
V3)OFF (Closed) OFF (Closed) Closed Open Ð
*1: Also includes conditions, in which the engine is stopped with the ignition switch ON or the atmospheric pressure is below 90.0
kPa (900 mbar, 675 mmHg, 26.57 inHg).
DEC026
EGR SYSTEMTD
EC-212

Wiring Diagram
TD25 ENGINE (LHD)
HEC579
EGR SYSTEMTD
EC-213

TD25 ENGINE (LHD)
HEC580
EGR SYSTEMTD
Wiring Diagram (Cont'd)
EC-214

TD25 ENGINE (RHD)
HEC581
EGR SYSTEMTD
Wiring Diagram (Cont'd)
EC-215

TD25 ENGINE (RHD)
HEC582
EGR SYSTEMTD
Wiring Diagram (Cont'd)
EC-216

System Inspection
OVERALL FUNCTION
1. Start engine and warm it up sufficiently.
2. Make sure that EGR valve diaphragm and throttle chamber
control valve rod movement (Use your finger to confirm EGR
valve diaphragm movement) under the following conditions.
At idle:
Diaphragm and rod do not move.
Revving engine from idle to between 1,000 and 2,800
rpm:
Diaphragm and rod move.
Keeping engine speed between 2,900 and 3,200 rpm:
Diaphragm and rod stay in open position.
POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect EGRC-solenoid valve A and B harness connec-
tor.
3. Turn ignition switch ON.
4. Check voltage between terminal
V2and ground.
Voltage: Battery voltage
OUTPUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between terminals.
Continuity should exist.
If OK, check harness for short.
EGRC-solenoid valve A:
ECM terminal
V36and terminalV1orV11
EGRC-solenoid valve B:
ECM terminal
V34and terminalV1orV11
DEC027
DEC028
DEC029
SEF674P
DEC041
EGR SYSTEMTD
EC-217

INPUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between terminals.
Continuity should exist.
If OK, check harness for short.
Potentiometer:
ECM terminal
V31and terminalV19orV20.
ECM terminal
V23and terminalV19orV20.
Engine revolution sensor:
ECM terminal
V9and terminalV19orV20.
Engine coolant temperature sensor:
Refer to ``Glow Control Unit Inspection'' in ``QUICK-GLOW
SYSTEM'', EC-206.
Component Inspection
EGR valve
Apply vacuum to EGR vacuum port with a hand vacuum pump.
EGR valve diaphragm should lift.
If NG, replace EGR valve.
Throttle chamber control valve
Apply vacuum to throttle chamber control valve vacuum port with
a hand vacuum pump.
Throttle chamber control valve should close.
If NG, replace throttle chamber control valve.
EGRC-solenoid valve A and B
Check air passage continuity.
ConditionAir passage continuity
betweenVAandVB
Air passage continuity
between
VAandVC
12V direct current supply
between terminals
V1
andV2
Yes No
No supply No Yes
If NG, replace solenoid valve(s).
DEC042
MEF137D
DEC030
MEC488B
EGR SYSTEMTD
System Inspection (Cont'd)
EC-218