Downloaded from www.Manualslib.com manuals search engine 6-24 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Engine has no power
Engine overheating Refer to “Overheating” of this table.
Faulty ignition coil Ignition coil assembly in Section 6F.
Faulty knock sensor Knock sensor malfunction in this sec-
tion.
Fuel pressure out of specification Diagnostic Flow Table B-3
Faulty injector Diagnostic Flow Table B-1
Faulty TP sensor, ECT sensor or MAP
sensorTP sensor, ECT sensor or MAP sen-
sor in Section 6E.
Faulty ECM Inspection of ECM and its circuit in
this section.
Malfunctioning EGR valve (if equipped) EGR system in Section 6E.
Maladjusted accelerator cable play Accelerator cable adjustment in Sec-
tion 6E.
Low compression Previously outlined.
Dragging brakes Diagnosis table in Section 5.
Slipping clutch Diagnosis table in Section 7C.
Improper engine idling
or engine fails to idleFaulty ignition coil Ignition coil assembly in Section 6F.
Engine overheating Refer to “Overheating” of this table.
Fuel pressure out of specification Diagnostic Flow Table B-3
Faulty idle air control system Diagnostic Flow Table B-4
Faulty evaporative emission control sys-
temEVAP control system in Section 6E.
Faulty injector Diagnostic Flow Table B-1
Faulty ECT sensor, TP sensor or MAP
sensorECT sensor, TP sensor or MAP sen-
sor in Section 6E.
Malfunctioning PCV system PCV system in Section 6F.
Faulty ECM Inspection of ECM and its circuit in
this section.
Faulty EGR system (if equipped) EGR system in Section 6E.
Low compression Previously outlined.
Engine hesitates
(Momentary lack of
response as the accel-
erator is depressed.
Can occur at all vehicle
speeds.
Usually most severe
when first trying to
make the vehicle move,
as from a stop sign.)Faulty ignition coil Ignition coil assembly in Section 6F.
Engine overheating Refer to “Overheating” of this table.
Fuel pressure out of specification Diagnostic Flow Table B-3
Faulty injector Diagnostic Flow Table B-1
Faulty TP sensor, ECT sensor or MAP
sensorTP sensor, ECT sensor or MAP sen-
sor in Section 6E.
Faulty ECM Inspection of ECM and its circuit in
this section.
Malfunctioning EGR valve (if equipped) EGR system in Section 6E.
Low compression Previously outlined.
Surges
(Engine power variation
under steady throttle or
cruise.
Feels like the vehicle
speeds up and down
with no change in the
accelerator pedal.)Faulty ignition coil or high-tension cord Ignition coil assembly or high-tension
cords in Section 6F.
Variable fuel pressure Diagnostic Flow Table B-3
Faulty MAP sensor MAP sensor in Section 6E.
Faulty injector Diagnostic Flow Table B-1
Faulty ECM Inspection of ECM and its circuit in
this section.
Malfunctioning EGR valve (if equipped) EGR system in Section 6E. Condition Possible Cause Reference Item
Downloaded from www.Manualslib.com manuals search engine ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-25
Excessive detonation
(The engine makes
sharp metallic knocks
that change with throt-
tle opening.
Sounds like pop corn
popping.)Engine overheating Refer to “Overheating” of this table.
Faulty spark plug Spark plugs in Section 6F.
Clogged fuel filter and fuel lines Diagnostic Flow Table B-3
Malfunctioning EGR valve (if equipped) EGR system in Section 6E.
Poor performance of knock sensor, ECT
sensor or MAP sensorKnock sensor in this section, ECT
sensor or MAP sensor in Section 6E.
Faulty injector Diagnostic Flow Table B-1
Faulty ECM Inspection of ECM and its circuit in
this section.
Excessive combustion chamber deposits Piston and cylinder head in Section
6A1.
Overheating
Inoperative thermostat Thermostat in Section 6B.
Faulty A/C condenser fan motor or its cir-
cuitA/C condenser fan control system
check in Section 6E.
Loose or slip water pump belt ITEM1-1 Drive belt inspection and
change in Section 0B.
Poor water pump performance Water pump in Section 6B.
Clogged or leaky radiator Radiator in Section 6B.
Improper engine oil grade ITEM1-3 Engine oil and oil filter
change in Section 0B.
Clogged oil filter or oil strainer Oil pressure check in Section 6A1.
Poor oil pump performance Oil pressure check in Section 6A1.
Dragging brakes Diagnosis Table in Section 5.
Slipping clutch Diagnosis Table in Section 7C.
Blown cylinder head gasket Valves and cylinder head in Section
6A1.
Poor gasoline mileage
Faulty ignition coil Ignition coil assembly in Section 6F.
Fuel pressure out of specification Diagnostic Flow Table B-3
Faulty TP sensor, ECT sensor or MAP
sensorTP sensor, ECT sensor or MAP sen-
sor in Section 6E.
Faulty injector Diagnostic Flow Table B-1
Faulty ECM Inspection of ECM and its circuit in
this section.
Malfunctioning EGR valve (if equipped) EGR system in Section 6E.
High idle speed Refer to item “Improper Engine Idle
Speed” previously outlined.
Low compression Previously outlined.
Poor valve seating Valves and cylinder head in Section
6A1.
Dragging brakes Diagnosis Table in Section 5.
Slipping clutch Diagnosis Table in Section 7C.
Thermostat out of order Thermostat in Section 6B.
Improper tire pressure Refer to Section 3F. Condition Possible Cause Reference Item
Downloaded from www.Manualslib.com manuals search engine 6-26 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Excessive engine oil
consumptionSticky piston ring Pistons, piston rings, connecting rods
and cylinders in Section 6A1.
Worn piston and cylinder Pistons, piston rings, connecting rods
and cylinders in Section 6A1.
Worn piston ring groove and ring Pistons, piston rings, connecting rods
and cylinders in Section 6A1.
Improper location of piston ring gap Pistons, piston rings, connecting rods
and cylinders in Section 6A1.
Worn or damaged valve stem seal Valves and cylinder head in Section
6A1.
Worn valve stem Valves and cylinder head in Section
6A1.
Low oil pressure
Improper oil viscosity ITEM1-3 Engine oil and oil filter
change in Section 0B.
Malfunctioning oil pressure switch Oil pressure switch in Section 8.
Clogged oil strainer Oil pan and oil pump strainer in Sec-
tion 6A1.
Functional deterioration of oil pump Oil pump in Section 6A1.
Worn oil pump relief valve Oil pump in Section 6A1.
Excessive clearance in various sliding
partsRefer to Section 6A1.
Engine noise
See NOTE below.Improper valve lash Valve lash in Section 6A1.
Worn valve stem and guide Valves and cylinder head in Section
6A1.
Weak or broken valve spring Valve springs in Section 6A1.
Warped or bent valve Valves and cylinder head in Section
6A1.
Loose camshaft housing bolts Camshaft in Section 6A1.
Worn piston, ring and cylinder bore Pistons and cylinders in Section 6A1.
Worn crankpin bearing Crankpin and connecting rod bearing
in Section 6A1.
Worn crankpin Crankpin and connecting rod bearing
in Section 6A1.
Loose connecting rod nuts Connecting rod in Section 6A1.
Low oil pressure Previously outlined.
Worn crankshaft journal bearing Main bearings, Crankshaft and cylin-
der block in Section 6A1.
Worn crankshaft journal Main bearings, Crankshaft and cylin-
der block in Section 6A1.
Loose lower crankcase (bearing cap) bolts Main bearings, Crankshaft and cylin-
der block in Section 6A1.
Excessive crankshaft thrust play Main bearings, Crankshaft and cylin-
der block in Section 6A1. Condition Possible Cause Reference Item
NOTE:
Before checking the mechanical noise, make sure that :
Ignition timing is properly adjusted.
Specified spark plug is used.
Specified fuel is used.
Downloaded from www.Manualslib.com manuals search engine ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-27
Condition Possible Cause Reference Item
Excessive hydrocar-
bon (HC) emission or
Excessive carbon mon-
oxide (CO) emissionFaulty ignition coil Ignition coil assembly in Section 6F.
Fuel pressure out of specification Diagnostic Flow Table B-3
Lead contamination of three way catalytic
converterMaintenance in Section 6K.
Malfunctioning PCV system PCV system in Section 6E.
Faulty EVAP control system EVAP control system in Section 6E.
Closed loop system (A/F feed back com-
pensation) fails
–Faulty TP sensor
–Faulty ECT sensor or MAP sensor
–Faulty oxygen sensorCheck oxygen sensor output voltage.
Refer to DTC P0130 (No.14) Table in
this section.
Faulty injector Diagnostic Flow Table B-1
Faulty ECM Inspection of ECM and its circuit in
this section.
Low compression Previously outlined.
Excessive nitrogen
oxides (NOx) emissionFuel pressure out of specification Diagnostic Flow Table B-3
Lead contamination of three way catalytic
converterMaintenance in Section 6K.
Closed loop system (A/F feed back com-
pensation) fails
–Faulty TP sensor
–Faulty ECT sensor or MAP sensor
–Faulty oxygen sensorCheck oxygen sensor output voltage
Refer to DTC P0130 (No.14) Table in
this section.
Faulty injector Diagnostic Flow Table B-1
Faulty ECM Inspection of ECM and its circuit in
this section.
Faulty EGR system (if equipped) EGR system in Section 6E.
Downloaded from www.Manualslib.com manuals search engine 6-34 ENGINE GENERAL INFORMATION AND DIAGNOSIS
ECM TERMINAL VOLTAGE VALUES TABLE
For TYPE A (See NOTE)
NOTE:
Type A is other than follows.
Type B is left hand steering vehicle equipped with fasten seat belt light and EGR valve or right hand
steering vehicle equipped with fasten seat belt light and immobilizer control system.
TERMINAL
NO.CIRCUIT NORMAL
VOLTAGECONDITION
E191Ground––
2Ground––
3Ground––
4 EVAP canister purge valve 10 – 14 V Ignition switch ON
5Power steering pressure switch
(if equipped)0 – 1.3 VWhile engine running at idle speed, turn
steering wheel to right or left as far as it
stops
10 – 14 V Ignition switch ON
6 Idle air control valve 0 – 13 VAt specified idle speed after engine
warmed up
7 Heater of HO2S-1 10 – 14 V Ignition switch ON
8 Fuel injector NO.4 10 – 14 V Ignition switch ON
9 Fuel injector NO.1 10 – 14 V Ignition switch ON
10 Sensor ground––
11 Camshaft position sensor0 – 0.8 V and
4 – 6 VIgnition switch ON
12–– –
13Heater oxygen sensor-1 Refer to DTC P0130 diag. flow table
CO adjusting resistor (w/o HO2S) 0 – 5 V Ignition switch ON position
14
Engine coolant temp. sensor 0.55 - 0.95 VIgnition switch ON
Engine coolant temp. : 80 °C (176 °F)
15
Intake air temp. sensor 2.0 – 2.7 VIgnition switch ON
Intake air temp. : 20 °C (68 °F)
16 Throttle opening signal0.2 – 1.0 VIgnition switch ON position and throttle
valve at idle position
2.8 – 4.8 VIgnition switch ON position and throttle
valve fully open
17EGR valve (stepper motor coil 3, if
equipped)10 – 14 VIgnition switch ON position leaving engine
OFF
18EGR valve (stepper motor coil 1, if
equipped)10 – 14 VIgnition switch ON position leaving engine
OFF
19 Ignition coil #2––
20 Ignition coil #1––
21 Fuel injector NO.2 10 – 14 V Ignition switch ON
22 Power source for sensors 4.75 – 5.25 V Ignition switch ON
23 Crankshaft position sensor0 – 0.8 or
4 – 5 VIgnition switch ON position
24–– –
25 Knock sensor About 2.5 VAt specified idle speed after engine
warmed up
Downloaded from www.Manualslib.com manuals search engine ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-35
For TYPE B (See NOTE)
E1926 Manifold absolute pressure sensor 3.3 – 4.0 VIgnition switch ON
Barometric pressure : 100 kPa
(760 mmHg)
27 A/C evaporator temp. sensor 2.0 – 2.3 VIgnition switch ON A/C evaporation temp.
sensor at 25 °C (77 °F)
28EGR valve (stepper motor coil 4, if
equipped)10 – 14 VIgnition switch ON position leaving engine
OFF
29EGR valve (stepper motor coil 2, if
equipped)10 – 14 VIgnition switch ON position leaving engine
OFF
30–– –
31 Fuel injector NO.3 10 – 14 V Ignition switch ON TERMINAL
NO.CIRCUIT NORMAL
VOLTAGECONDITION
NOTE:
See NOTE in “ECM TERMINAL VOLTAGE VALUES TABLE” for applicable model.
TERMINAL
NO.CIRCUIT NORMAL
VOLTAGECONDITION
E191 Ground––
2 Ground––
3 Ground––
4 EVAP canister purge valve 10 – 14 V Ignition switch ON
5Power steering pressure switch
(if equipped)0 – 1.3 VWhile engine running at idle speed, turn
steering wheel to right or left as far as it
stops
10 – 14 V Ignition switch ON
6 Idle air control valve 0 – 13 VAt specified idle speed after engine
warmed up
7 Heater of HO2S-1 10 – 14 V Ignition switch ON
8 Fuel injector NO.4 10 – 14 V Ignition switch ON
9 Fuel injector NO.1 10 – 14 V Ignition switch ON
10 Sensor ground––
11 Camshaft position sensor0 – 0.8 V and
4 – 6 VIgnition switch ON
12–– –
13Heater oxygen sensor-1 Refer to DTC P0130 diag. flow table
CO adjusting resistor (w/o HO2S) 0 – 5 V Ignition switch ON position
14 Engine coolant temp. sensor 0.55 - 0.95 VIgnition switch ON
Engine coolant temp. : 80 °C (176 °F)
15 Intake air temp. sensor 2.0 – 2.7 VIgnition switch ON
Intake air temp. : 20 °C (68 °F)
16 Throttle opening signal0.2 – 1.0 VIgnition switch ON position and throttle
valve at idle position
2.8 – 4.8 VIgnition switch ON position and throttle
valve fully open
17EGR valve (stepper motor coil 3, if
equipped)10 – 14 VIgnition switch ON position leaving engine
OFF
Downloaded from www.Manualslib.com manuals search engine 6-36 ENGINE GENERAL INFORMATION AND DIAGNOSIS
For TYPE A (See NOTE)
E1918EGR valve (stepper motor coil 1, if
equipped)10 – 14 VIgnition switch ON position leaving engine
OFF
19 Ignition coil #2––
20 Ignition coil #1––
21 Fuel injector NO.2 10 – 14 V Ignition switch ON
22 Power source for sensors 4.75 – 5.25 V Ignition switch ON
23 Crankshaft position sensor0 – 0.8 or
4 – 5 VIgnition switch ON position
24–– –
25 Knock sensor About 2.5 VAt specified idle speed after engine
warmed up
26 Manifold absolute pressure sensor 3.3 – 4.0 VIgnition switch ON
Barometric pressure : 100 kPa
(760 mmHg)
27–– –
28EGR valve (stepper motor coil 4, if
equipped)10 – 14 VIgnition switch ON position leaving engine
OFF
29EGR valve (stepper motor coil 2, if
equipped)10 – 14 VIgnition switch ON position leaving engine
OFF
30–– –
31 Fuel injector NO.3 10 – 14 V Ignition switch ON TERMINAL
NO.CIRCUIT NORMAL
VOLTAGECONDITION
NOTE:
See NOTE in “ECM TERMINAL VOLTAGE VALUES TABLE” for applicable model.
TERMINAL
NO.CIRCUIT NORMAL
VOLTAGECONDITION
E181 A/C compressor clutch 0 V Ignition switch ON
2 Malfunction indicator lamp10 – 14 V Engine running
0 – 1.0 V Ignition switch ON leaving engine OFF
3 Data link connector 10 – 14 V Ignition switch ON
4 Heater of HO2S-2 (if equipped) 10 – 14 V Ignition switch ON
5 Power source 10 – 14 V Ignition switch ON
6 Power source 10 – 14 V Ignition switch ON
7 Power source for buck-up 10 – 14 V Ignition switch ON and OFF
8Immobilizer indicator lamp
(with immobilizer indicator lamp)10 – 14 V Engine running
0 – 1.0 V Ignition switch ON leaving engine OFF
Duty output terminal (without
immobilizer indicator lamp)0 – 1.0 V Ignition switch ON
9–– –
10 Main relay10 – 14 V Ignition switch OFF
0.4 – 1.5 V Ignition switch ON
11 Tachometer––
12 Data link connector 4 – 5 V Ignition switch ON
13 Heated oxygen sensor-2 Refer to DTC P0130 diag. flow table
Downloaded from www.Manualslib.com manuals search engine ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-41
Resistance Check
1) Disconnect ECM couplers (1) from ECM with ignition switch
OFF.
2) Check resistance between each terminal of couplers discon-
nected. CAUTION:
Never touch terminals of ECM itself or connect voltmeter
or ohmmeter (2).
CAUTION:
Be sure to connect ohmmeter probe from wire harness
side of coupler.
Be sure to turn OFF ignition switch for this check.
Resistance in table below represents that when parts
temperature is 20 °C (68 °F).
1. ECM coupler disconnected
2. Ohmmeter
TERMINALS CIRCUIT STANDARD RESISTANCE
E19-7 to E17-9
(For TYPE A) (See NOTE)HO2S-1 heater 5 – 6.4 Ω
E19-7 to E18-11
(For TYPE B) (See NOTE)
E18-4 to E17-9
(For TYPE A) (See NOTE)HO2S-2 heater 11.7 – 14.3 Ω
E19-9 to E19-2 No.1 injector 12.0 – 13.0 Ω
E19-21 to E19-2 No.2 injector 12.0 – 13.0 Ω
E19-31 to E19-2 No.3 injector 12.0 – 13.0 Ω
E19-8 to E19-2 No.4 injector 12.0 – 13.0 Ω
E19-28 to E19-2 EGR valve (stepper motor coil 4) 20 – 24 Ω
E19-17 to E19-2 EGR valve (stepper motor coil 3) 20 – 24 Ω
E19-29 to E19-2 EGR valve (stepper motor coil 2) 20 – 24 Ω
E19-18 to E19-2 EGR valve (stepper motor coil 1) 20 – 24 Ω
E19-4 to E19-2 EVAP canister purge valve 30 – 34 Ω
E18-19 to E17-9 (For
TYPE A) (See NOTE)Fuel pump relay 70 – 110 Ω
E18-19 to E18-11 (For
TYPE B) (See NOTE)
E18-1 to Body ground A/C compressor clutch 3 – 4.5 Ω
E18-18 to E19-2 A/C condenser fan control relay 70 – 110 Ω
E18-10 to E18-7 Main relay 70 – 110 Ω
E19-1 to Body ground Ground Continuity
E19-2 to Body ground Ground Continuity
E19-3 to Body ground Ground Continuity
NOTE:
For TYPE A and TYPE B, refer to the NOTE in “ECM Terminal Voltage Values Table” for applicable
model.