Page 377 of 2267
YEC804
BATTERY
Refer to EL-POWER.
: Detectable line for DTC
: Non-detectable line for DTC
ENGINE
CONTROL
MODULE
RELAYINJECTION PUMP (INJEC-
TION TIMING CONTROL
VA LV E )
ECM
TROUBLE DIAGNOSIS 6CD20T
Injection Timing Control Valve (Cont'd)
EC-83
Page 378 of 2267

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK FOR AIR IN FUEL FILTER.
1. Move priming pump up and down to
purge air from fuel filter.
2. Perform ªDIAGNOSTIC TROUBLE
CODE CONFIRMATION PROCE-
DUREº.
CHECK POWER SUPPLY.
1. Turn ignition switch to ªLOCKº posi-
tion.
2. Disconnect injection timing control
valve harness connector.
3. Turn ignition switch to ªONº position.
4. Check voltage between injection tim-
ing control valve connector terminal
p3and ground with CONSULT-II or
tester.
Voltage: Battery voltage
OK
ENG
Check the following:
lHarness connectors
E89,F96
lElectronic injection
pump harness connec-
tor
F49
l15A fuse
lHarness for open or
short-circuit between
injection timing control
valve harness connec-
tor and ECM relay.
If NG, repair harness or
connectors.
CHECK OUTPUT SIGNAL CIRCUIT.
1. Turn ignition switch to ªLOCKº posi-
tion.
2. Disconnect ECM harness connector.
3. Check harness continuity between
injection timing control valve connec-
tor terminal
p2and ECM terminals
202.
Continuity should exist.
If OK, check harness for short-cir-
cuit.
OK
ENG
Check the following:
lElectronic injection
pump harness connec-
tor
F49
lHarness for open or
short-circuit between
injection timing control
valve and ECM.
If NG, repair harness or
connectors.
pA
SEF671S
Priming pump
NEF804
Fuel injection timing
control valve harness
connector
NEF201A
Injection timing control
valve harness connector
NEF202A
Injection timing control
valve harness connector
H
H
H
H
TROUBLE DIAGNOSIS 6CD20T
Injection Timing Control Valve (Cont'd)
EC-84
Page 379 of 2267
pA
CHECK COMPONENT
(Injection timing control valve).
Refer to ªCOMPONENT INSPECTIONº
below.
OK
ENG
Replace injection timing
control valve.
Disconnect and reconnect harness con-
nectors in the circuit. Then retest.
Trouble is not fixed.
Check ECM pin terminals for damage
and check the connection of ECM har-
ness connector. Reconnect ECM har-
ness connector and retest.
INSPECTION END
COMPONENT INSPECTION
Injection timing control valve
1. Disconnect injection timing control valve harness connector.
2. Check resistance between terminals
p2andp3.
Resistance: Approximately 15W[at 25ÉC (77ÉF)]
If NG, replace injection timing control valve.
YEC364 Injection timing
control valve
H
H
H
H
TROUBLE DIAGNOSIS 6CD20T
Injection Timing Control Valve (Cont'd)
EC-85
Page 380 of 2267
Engine Control Module (ECM)
The ECM consists of a microcomputer and connectors for signal
input and output and for power supply. The module monitors and
controls the engine operation.
Malfunction is detected when ....Check Item
(Possible Cause)
lECM calculation function is malfunctioning.lECM *
lAn excessively high or low voltage from the atmospheric
pressure sensor is detected by the ECM.lECM *
lECM reference voltage (2.5V) is excessively high or low.lECM *
lECM version number or switching function is not plausible.lECM *
lIgnition switch ªONº signal evaluation circuit in ECM is
malfunctioning.lECM *
* Actually inspecting the ECM inside circuit is impossible. Then, ECM may be replaced.
DIAGNOSTIC TROUBLE CONFIRMATION
PROCEDURE
1) Turn ignition switch to ªONº position.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 2 seconds.
SEC220B
TROUBLE DIAGNOSIS 7CD20T
EC-86
Page 381 of 2267

Cooling Fan (Overheat)
SYSTEM DESCRIPTION
Vehicle speed sensorEVehicle speed
ECM
ECooling
fan
relay(s)Engine coolant temperature sensorEEngine coolant temperature
Air conditioner switch
EAir conditioner ªONº signal
The ECM controls the cooling fan corresponding to the vehicle speed, engine coolant temperature, air con-
ditioner system pressure and air conditioner ON signal. The control system has 3-step control [HIGH/LOW/
OFF]. This system indirectly relates to diagnostic trouble code 28 (Overheat).
Operation
ON-BOARD DIAGNOSIS LOGIC
This diagnosis continuously monitors the engine coolant temperature.
If the cooling fan or another component in the cooling system malfunctions, engine coolant temperature will
rise.
When the engine coolant temperature reaches an abnormally high temperature condition, a malfunction is
indicated.
Malfunction is detected when ...Check Items
(Possible Cause)
lAn excessive high engine coolant temperature sensor sig-
nal is detected by the ECM. (Overheat)lHarness or connectors
(The cooling fan circuit is open or shorted.)
lCooling fan
lRadiator hose
lRadiator
lRadiator cap
lWater pump
lThermostat
lFan belt
lEngine coolant temperature sensor
For more information, refer to ª12 MAIN CAUSES OF
OVERHEATINGº, EC-CD-95.
CAUTION:
When a malfunction is indicated, be sure to replace the coolant following the procedure in the MA
section (ªChanging Engine Coolantº, ªENGINE MAINTENANCEº). Also, replace the engine oil.
a. Fill radiator with coolant up to specified level with a filling speed of 2 liters per minute. Be sure
to use coolant with the proper mixture ratio. Refer to MA section (ªAnti-freeze Coolant Mixture
Ratioº, ªRECOMMENDED FLUIDS AND LUBRICANTSº).
b. After refilling coolant, run engine to ensure that no water-flow noise is emitted.
NEF772
Engine coolant
temperature ÉC (ÉF)
Air conditioner is OFF
.102 (216)
.96 (205)
.20
(12).80
(50)
Vehicle speed km/h (mph)
Cooling fans do not operateCooling fans operate at high speed
Engine coolant
temperature ÉC (ÉF)
Vehicle speed km/h (mph)
.20
(12).80
(50)
.102 (216)
.96 (205)Air conditioner is ON
Cooling fans operate at low speed
TROUBLE DIAGNOSIS 8CD20T
EC-87
Page 382 of 2267

OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the cooling
fan. During this check, a DTC might not be confirmed.
WARNING:
Never remove the radiator cap when the engine is hot. Seri-
ous burns could be caused by high pressure fluid escaping
from the radiator.
Wrap a thick cloth around the cap. Carefully remove the cap
by turning it a quarter turn to allow built-up pressure to
escape. Then turn the cap all the way off.
1) Check the coolant level in the reservoir tank and radiator.
Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is
below the proper range, skip the following steps and go to
ªDIAGNOSTIC PROCEDUREº, EC-CD-90.
2) Confirm whether customer filled the coolant or not. If cus-
tomer filled the coolant, skip the following steps and go to
ªDIAGNOSTIC PROCEDUREº, EC-CD-90.
3) Turn ignition switch to ªONº position.
4) Perform ªCOOLING FANº in ªACTIVE TESTº mode
with CONSULT-II (LOW speed and HI speed).
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
3) Start engine.
Be careful not to overheat engine.
4) Set temperature control switch to full cold position.
5) Push Air Conditioner switch to ªONº position.
6) Turn blower fan switch to ªONº position.
7) Run engine at idle for a few minutes with Air Con-
ditioner operating.
Be careful not to overheat engine.
8) Make sure that both cooling fans operate at low
speed.
9) Turn ignition switch to ªLOCKº position.
10) Push Air Conditioner switch and blower fan switch
to ªOFFº position.
11) Disconnect engine coolant temperature sensor
harness connector.
12) Connect 150Wresistor to engine coolant tempera-
ture sensor harness connector.
13) Restart engine and make sure that both cooling
fans operate at higher speed than low speed.
Be careful not to overheat engine.
AEC640 MAX.
MIN.OK
SEF111X
SEC163BA
MEC475B Cooling fan
Engine coolant
temperature sensor
harness connector
150Wresistor
TROUBLE DIAGNOSIS 8CD20T
Cooling Fan (Overheat) (Cont'd)
EC-88
Page 383 of 2267
YEC805
BATTERYIGNITION SWITCH
ON or START
FUSE
BLOCK
(J/B)Refer to EL-POWER.
: Detectable line for DTC
: Non-detectable line for DTC
COOLING
FA N
RELAY-3COOLING
FA N
RELAY-2COOLING
FA N
RELAY-1
COOLING
FA N
MOTOR-1
LOWHIGHTRIPLE-
PRESSURE
SWITCHCOOLING
FA N
MOTOR-2
ECM
REFER TO THE FOLLOWING
FUSE BLOCK - Junction Box (J/B)
TROUBLE DIAGNOSIS 8CD20T
Cooling Fan (Overheat) (Cont'd)
EC-89
Page 384 of 2267

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK COOLING FAN LOW
SPEED OPERATION.
1. Disconnect cooling fan relay-3.
2. Turn ignition switch to ªONº
position.
3. Perform ªCOOLING FANº
in ªACTIVE TESTº mode
with CONSULT-II.
-------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------
2. Start engine.
3. Set temperature switch at
full cold position.
4. Turn Air Conditioner switch
to ªONº position.
5. Turn blower fan switch to
ªONº position.
6. Run engine at idle speed
for a few minutes with Air
Conditioner operating.
7. Make sure that both cool-
ing fans operate at low
speed.
OK
ENG
Check cooling fan low
speed control circuit.
(Go to
PROCEDURE A
.)
CHECK COOLING FAN HIGH
SPEED OPERATION.
1. Turn ignition switch to ªLOCKº
position.
2. Reconnect cooling fan relay-3.
3. Disconnect cooling fan relay-1.
4. Turn ignition switch to ªONº
position.
5. Perform ªCOOLING FANº
in ªACTIVE TESTº mode
with CONSULT-II.
-------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------
4. Turn Air Conditioner switch
and blower fan switch to
ªOFFº position.
5. Disconnect engine coolant
temperature sensor har-
ness connector.
6. Connect 150Wresistor to
engine coolant temperature
sensor harness connector.
7. Restart engine and make
sure that both cooling fans
operate at higher speed
than low speed.
OK
ENG
Check cooling fan high
speed control circuit.
(Go to
PROCEDURE B
.)
pB
(Go to EC-CD-94.)
.Cooling fan relay 2
Cooling fan relay-1Cooling fan relay-3
YEC383
SEF111X
NEF809
Cooling fan
SEF111X
YEC384
Cooling fan
Engine coolant
temperature sensor
harness connector
resistor
H
H
H
TROUBLE DIAGNOSIS 8CD20T
Cooling Fan (Overheat) (Cont'd)
EC-90