
DIAGNOSTIC PROCEDURE
INSPECTION START
1) Turn ignition switch ``ON''.
2) Select ``SELF DIAG RESULTS''
mode with CONSULT.
3) Touch ``ERASE''.
--------------------------------------------------------------------------------------------------------------------------------------OR--------------------------------------------------------------------------------------------------------------------------------------
1) Turn ignition switch ``ON''.
2) Erase the Diagnostic Test Mode
II (Self-diagnostic results)
memory.
PERFORM SELF-DIAGNOSIS.
Select ``SELF DIAG RESULTS''
mode with CONSULT.
--------------------------------------------------------------------------------------------------------------------------------------OR--------------------------------------------------------------------------------------------------------------------------------------
PERFORM ``Diagnostic Test Mode
II'' (SELF-DIAGNOSTIC
RESULTS).
Is the DTC 27, 31 displayed again?
No
cYe s
Replace ECM.
INSPECTION END
.
.
.
.
TROUBLE DIAGNOSIS FOR ``ECM 1'' (DTC 27), ``ECM 2'' (DTC 31)
Engine Control Module (ECM)-ECCS-D Control
Module (Cont'd)
EC-112

OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the cooling fan.
During this check, a DTC might not be con®rmed.
WARNING:
Never remove the radiator cap when the engine is hot. Serious
burns could be caused by high pressure ¯uid 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 ``DIAG-
NOSTIC PROCEDURE'', EC-117.
2) Con®rm whether customer ®lled the coolant or not. If customer
®lled the coolant, skip the following steps and go to ``DIAGNOS-
TIC PROCEDURE'', EC-117.
3) Turn ignition switch ``ON''.
4) Perform ``COOLING FAN'' in ``ACTIVE TEST'' mode with
CONSULT and make sure that cooling fan operates
when touching ``ON''.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
3) Disconnect engine coolant temperature sensor harness
connector.
4) Connect 150Wresistor to engine coolant temperature
sensor harness connector.
5) Start engine and make sure that cooling fan operates.
Be careful not to overheat engine.
AEC640
SEF758V
SEF979S
TROUBLE DIAGNOSIS FOR ``OVER HEAT'' (DTC 28)
Cooling Fan (Overheat) (Cont'd)
EC-115

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK COOLING FAN OPERATION.
1. Turn ignition switch ``OFF''.
2. Turn ignition switch ``ON''.
3. Perform ``COOLING FAN'' in
``ACTIVE TEST'' mode with
CONSULT and make sure that
cooling fan operates when touch-
ing ``ON''.
--------------------------------------------------------------------------------------------------------------------------------------OR--------------------------------------------------------------------------------------------------------------------------------------
2. Disconnect engine coolant tem-
perature sensor harness connec-
tor.
3. Connect 150Wresistor to engine
coolant temperature sensor har-
ness connector.
4. Start engine and make sure that
cooling fan operates.
NG
cOK
Go to``CHECK COOL-
ING SYSTEM FOR LEAK'',
EC-119.
CHECK POWER SUPPLY.
1. Turn ignition switch ``OFF''.
2. Disconnect cooling fan relay-1.
3. Turn ignition switch ``ON''.
4. Check voltage between terminals
V2,
V5and ground with CONSULT or tester.
Voltage: Battery voltage
OK
cNG
Check the following.
+10A fuse
+30A fusible link
+Harness for open or short
between cooling fan
relay-1 and fuse
+Harness for open or short
between cooling fan
relay-1 and battery
If NG, repair harness or
connectors.
CHECK GROUND CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect cooling fan motor harness
connector.
3. Check harness continuity between
relay terminal
V3and motor termi-
nals
V1,V3.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
4. Check harness continuity between
motor terminals
V2,V4and body
ground.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
jA
SEF758V
SEF979S
SEF690V
SEF759V
SEF691V
.
.
.
.
TROUBLE DIAGNOSIS FOR ``OVER HEAT'' (DTC 28)
Cooling Fan (Overheat) (Cont'd)
EC-117

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

Charge Air Temperature Sensor
The charge air temperature sensor is used to detect the charge air
temperature. The sensor modi®es a voltage signal from the ECM.
The modi®ed signal returns to the ECM as the charge air tempera-
ture input. The sensor uses a thermistor which is sensitive to the
change in temperature. The electrical resistance of the thermistor
decreases as temperature increases.
The ECM uses this signal for the charge air cooler control.
Charge air temperatureÉC (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
110 (230) 0.64 0.143 - 0.153
150 (302) 0.30 0.050 - 0.065
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
COLOR ITEM CONDITION DATA
(DC Voltage and Pulse Signal)
36 LG Charge air temperature
sensor Engine is running.
Approximatel
y 0 - 4.8V
Output voltage varies with
charge air temperature.
50 B Sensors' ground Engine is running.
(Warm-up condition)
Idle speed Approximately 0V
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code No. Malfunction is detected when ...
Check Items
(Possible Cause)
33 *1 +An excessively high or low voltage from the sensor is
entered to ECM. +
Harness or connectors
(The sensor circuit is open or shorted.)
+ Charge air temperature sensor
*1: When nothing is displayed or the meaningless symbol is displayed in the ``Self-diag result'' mode with CONSULT, perform ``Diagnostic Test Mode II
(Self-diagnostic results)'' with ECM. Refer to EC-32.
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
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
TROUBLE DIAGNOSIS FOR ``I/C INT/A TEMP SEN'' (DTC 33)
EC-122

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY.
1. Turn ignition switch ``OFF''.
2. Disconnect charge air temperature sen-
sor harness connector.
3. Turn ignition switch ``ON''.
4. Check voltage between terminal
V2
and ground with CONSULT or tester.
Voltage:
Approximately 5V
OK
cNG
Repair harness or connec-
tors.
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
F6,M51
+Harness connectors
M88,E106
+Harness for open or
short between ECM and
charge air temperature
sensor
+Harness for open or
short between TCM and
charge air temperature
sensor
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
CHECK COMPONENT
(Charge air temperature sensor).
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace charge air tem-
perature 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
SEF710V
SEF764V
SEF765V
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``I/C INT/A TEMP SEN'' (DTC 33)
Charge Air Temperature Sensor (Cont'd)
EC-124

DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
1) Turn ignition switch ``ON'' and select ``DATA MONITOR''
mode with CONSULT.
2) Start engine and run it for at least 10 seconds at idle
speed.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Start engine and run it for at least 10 seconds at idle
speed.
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.
SEF714V
TROUBLE DIAGNOSIS FOR ``NEEDLE LIFT SEN'' (DTC 34)
Needle Lift Sensor (NLS) (Cont'd)
EC-127

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK FOR AIR IN FUEL FILTER.
1. Move priming pump up and down to
purge air from fuel ®lter.
2. Perform ``DIAGNOSTIC TROUBLE
CODE CONFIRMATION PROCEDURE''.
NG
cOK
INSPECTION END
Loosen and retighten engine ground
screws.
CHECK INPUT SIGNAL CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect ECM harness connector and
needle lift sensor harness connector.
3. Check harness continuity between termi-
nal
V1and ECM terminalV34.
Continuity should exist.
If OK, check harness for short to ground
and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK GROUND CIRCUIT.
Check resistance between terminal
V2and
engine ground.
Continuity should exist.
If OK, check harness for short to ground
and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK NO. 1 INJECTION NOZZLE FOR
CLOGGING.
Refer to ``SPRAY PATTERN TEST'', ``Test
and Adjustment'', ``INJECTION NOZZLE'',
EC-26.
OK
cNG
Replace No. 1 injection
nozzle.
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
SEF670V
SEF676V
SEF692V
SEF766V
SEF767V
.
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``NEEDLE LIFT SEN'' (DTC 34)
Needle Lift Sensor (NLS) (Cont'd)
EC-129