
Downloaded from www.Manualslib.com manuals search engine 6-2 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Diagnostic trouble code (DTC) table ......... 6-16
Fail-safe table............................................ 6-19
Visual inspection ....................................... 6-20
Engine basic inspection ............................ 6-21
Engine diagnosis table .............................. 6-23
Scan Tool Data ............................................. 6-28
Scan tool data definitions .......................... 6-30
Inspection of ECM and Its Circuits ................ 6-33
Component Location ..................................... 6-42
Table A-1 Malfunction Indicator Lamp Circuit
Check - Lamp Does Not Come “ON” at Ignition
Switch ON (But Engine at Stop).................... 6-43
Table A-2 Malfunction Indicator Lamp Circuit
Check - Lamp Remains “ON” after Engine
Starts............................................................. 6-44
Table A-3 Malfunction Indicator Lamp Circuit
Check - Mil Flashes at Ignition Switch ON .... 6-45
Table A-4 Malfunction Indicator Lamp Circuit
Check - MIL Does Not Flash, Just Remains
ON or Just Remains OFF Even with Grounding
Diagnosis Switch Terminal............................ 6-45
Table A-5 ECM Power and Ground Circuit
Check - MIL Doesn’t Light at Ignition Switch
ON and Engine Doesn’t Start Though It Is
Cranked Up ................................................... 6-46
DTC P0105 (DTC No.11) Manifold Absolute
Pressure (MAP) Circuit Malfunction .............. 6-48
DTC P0110 (DTC No.18) Intake Air Temp.
(IAT) Circuit Malfunction ............................... 6-51
DTC P0115 (DTC No.19) Engine Coolant
Temperature (ECT) Circuit Malfunction ........ 6-53
DTC P0120 (DTC No.13) Throttle Position
Circuit Malfunction ........................................ 6-55
DTC P0121 Throttle Position Circuit Range /
Performance Problem ................................... 6-57
DTC P0130 (DTC No.14) Heated Oxygen
Sensor (HO2S) Circuit Malfunction
(Sensor-1) ..................................................... 6-59
DTC P0133 Heated Oxygen Sensor (HO2S)
Circuit Slow Response (Sensor-1) ................ 6-61
DTC P0135 (DTC No.14) Heated Oxygen
Sensor (HO2S) Heater Circuit Malfunction
(Sensor-1) ..................................................... 6-62
DTC P0136 Heated Oxygen Sensor (HO2S)
Circuit Malfunction (Sensor-2) ...................... 6-64
DTC P0141 Heated Oxygen Sensor (HO2S)
Heater Circuit Malfunction (Sensor-2)........... 6-66
DTC P0171 Fuel System Too Lean .............. 6-68
DTC P0172 Fuel System Too Rich ............... 6-68
DTC P0300 Random Misfire Detected
(Misfire Detected at 2 or More Cylinders) ..... 6-72DTC P0301 Cylinder 1 Misfire Detected ........ 6-72
DTC P0302 Cylinder 2 Misfire Detected ........ 6-72
DTC P0303 Cylinder 3 Misfire Detected ........ 6-72
DTC P0304 Cylinder 4 Misfire Detected ........ 6-72
DTC P0325 (DTC No.17) Knock Sensor Circuit
Malfunction .................................................... 6-77
DTC P0335 (DTC No.23) Crankshaft Position
(CKP) Sensor Circuit Malfunction .................. 6-79
DTC P0340 (DTC No.15) Camshaft Position
(CMP) Sensor Circuit Malfunction ................. 6-82
DTC P0400 Exhaust Gas Recirculation Flow
Malfunction .................................................... 6-85
DTC P0420 Catalyst System Efficiency below
Threshold ....................................................... 6-88
DTC P0443 Purge Control Valve Circuit
Malfunction .................................................... 6-91
DTC P0481 A/C Condenser Fan Control
Circuit Malfunction ......................................... 6-92
DTC P0500 (DTC No.16) Vehicle Speed
Sensor (VSS) Malfunction ............................. 6-94
DTC P0505 Idle Control System
Malfunction .................................................... 6-96
DTC P0601 Internal Control Module Memory
Check Sum Error (DTC No.71) ...................... 6-98
DTC P1450 Barometric Pressure Sensor
Low / High Input ............................................. 6-99
DTC P1451 Barometric Pressure Sensor
Performance Problem .................................... 6-99
DTC P1500 Engine Starter Signal Circuit
Malfunction .................................................. 6-101
DTC P1510 ECM Back-up Power Supply
Malfunction .................................................. 6-103
DTC P1570 (DTC No.21) ABS Signal Circuit
Malfunction .................................................. 6-104
DTC P1600 Serial Communication Problem
Between ECM and TCM .............................. 6-105
DTC P1717 A/T Drive Range (Park / Neutral
Position) Signal Circuit Malfunction ............. 6-107
Table B-1 Fuel Injector Circuit Check ..........6-109
Table B-2 Fuel Pump and Its Circuit
Check........................................................... 6-110
Table B-3 Fuel Pressure Check................... 6-112
Table B-4 Idle Air Control System Check ....6-114
Table B-5 A/C Signal Circuits Check
(Vehicle with A/C) ........................................ 6-117
Table B-6 Electric Load Signal Circuit
Check........................................................... 6-119
TAble B-7 A/C Condenser Fan Control
System Check.............................................. 6-121
Special Tool ................................................... 6-123

Downloaded from www.Manualslib.com manuals search engine ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-17
P0335
(No.23)Crankshaft position sensor
circuit malfunctionNo signal for 2 sec. During engine crank-
ing1 driving
cycle1 driving
cycle
P0340
(No.15)Camshaft position sensor
circuit malfunctionNo signal during engine running1 driving
cycle1 driving
cycle
P0400Exhaust gas recirculation
flow malfunction detectedExcessive or insufficient EGR flow2 driving
cyclesNot
applicable
P0420Catalyst system efficiency
below thresholdOutput waveforms of HO2S-1 and HO2S-2
are similar.
(Time from output voltage change of
HO2S-1 to that of HO2S-2 is shorter than
specification.)2 driving
cyclesNot
applicable
P0443Purge control valve circuit
malfunctionPurge control valve circuit is open or
shorted to ground2 driving
cyclesNot
applicable
P0481A/C condenser fan control
circuit malfunctionA/C condenser fan relay terminal voltage is
low when fan command is not outputted2 driving
cyclesNot
applicable
P0500
(No.16)Vehicle speed sensor mal-
functionNo signal while running in “D” range or
during fuel cut at decelerating2 driving
cycles1 driving
cycle
P0505 Idle control system malfunc-
tionNo closed signal to IAC valve is detected2 driving
cyclesNot
applicable
P0601
(No.71)Internal control module
memory check sum errorData write error (or check sum error) when
written into ECM2 driving
cyclesNot
applicable
P1450 Barometric pressure sen-
sor circuit malfunctionBarometric pressure is lower or higher
than specification. (or sensor malfunction)1 driving
cycleNot
applicable
P1451Barometric pressure sen-
sor performance problemDifference between manifold absolute
pressure (MAP sensor value) and baro-
metric pressure (barometric pressure sen-
sor value) is larger than specification
during cranking.2 driving
cyclesNot
applicable
P1500Starter signal circuit mal-
functionStarter signal is not inputted from engine
cranking till its start and after or it is always
inputted2 driving
cyclesNot
applicable
P1510ECM backup power source
malfunctionNo backup power after starting engine1 driving
cycleNot
applicable
P1600Serial communication prob-
lem between ECM and
TCMNo signal or check sum error while engine
running1 driving
cycleNot
applicable
P1717AT D-range signal circuit
malfunctionNo “D” range (park / neutral position sig-
nal) is inputted while vehicle running2 driving
cyclesNot
applicable
P1570ABS signal circuit malfunc-
tionABS signal ON (low voltage) when engine
startNot
applicable1 driving
cycle DTC
NO.DETECTING ITEM DETECTING CONDITION
(DTC will set when detecting :)MIL
(vehicle
with immo-
bilizer indi-
cator lamp)MIL
(vehicle
without
immobi-
lizer indica-
tor lamp)

Downloaded from www.Manualslib.com manuals search engine ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-19
Fail-safe table
When any of the following DTCs is detected, ECM enters fail-safe mode as long as malfunction continues to
exist but that mode is canceled when ECM detects normal condition after that.
DTC NO. DETECTED ITEM FAIL-SAFE OPERATION (SYMPTOM)
P0105
(No.11)Manifold absolute pressure sensor circuit
malfunctionECM uses value determined by throttle opening and
engine speed.
P0110
(No.18)Intake air temp. sensor circuit malfunctionECM controls actuators assuming that intake air tem-
perature is 20 °C (68 °F).
P0115
(No.19)Engine coolant temp. sensor circuit mal-
functionECM controls actuators assuming that engine coolant
temperature is 80 °C (176 °F).
P0120
(No.13)Throttle position sensor circuit malfunc-
tionECM controls actuators assuming that throttle opening
is 20°. (High idle speed)
P0335
(No.23)Crankshaft position sensor circuit mal-
functionECM controls injection system sequential injection to
synchronous injection. (Cranking for a few seconds to
start engine)
P0340
(No.15)Camshaft position sensor circuit malfunc-
tionECM controls injection system sequential injection to
synchronous injection. (Cranking for a few seconds to
start engine)
P0500
(No.16)Vehicle speed sensor malfunction ECM stops idle air control.
P1450Barometric pressure sensor low / high
inputECM controls actuators assuming that barometric
pressure is 100 kPa (760 mmHg).
P1570
(No.21)ABS signal circuit malfunctionECM controls actuators assuming that ABS signal is
OFF.

Downloaded from www.Manualslib.com manuals search engine 6-30 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Scan tool data definitions
FUEL SYSTEM (FUEL SYSTEM STATUS)
Air / fuel ratio feedback loop status displayed as either open or closed loop. Open indicates that ECM ignores
feedback from the exhaust oxygen sensor.
Closed indicates final injection duration is corrected for oxygen sensor feedback.
CALC LOAD (CALCULATED LOAD VALUE, %)
Engine load displayed as a percentage of maximum possible load. Value is calculated mathematically using the
formula : actual (current) intake air volume ÷ maximum possible intake air volume x 100%.
COOLANT TEMP. (ENGINE COOLANT TEMPERATURE, °C, °F)
It is detected by engine coolant temp. sensor
SHORT FT B1 (SHORT TERM FUEL TRIM, %)
Short term fuel trim value represents short term corrections to the air / fuel mixture computation. A value of 0
indicates no correction, a value greater than 0 means an enrichment correction, and a value less than 0 implies
an enleanment correction.
LONG FT B1 (LONG TERM FUEL TRIM, %)
Long term fuel trim Value represents long term corrections to the air / fuel mixture computation. A value of 0 indi-
cates no correction, a value greater than 0 means an enrichment correction, and a value less than 0 implies an
enleanment correction.
MAP (INTAKE MANIFOLD ABSOLUTE PRESSURE, kPa, inHg)
It is detected by manifold absolute pressure sensor and used (among other things) to compute engine load.
ENGINE SPEED (rpm)
It is computed by reference pulses from crankshaft position sensor.
VEHICLE SPEED (km/h, MPH)
It is computed based on pulse signals from vehicle speed sensor.
IGNITION ADVANCE (IGNITION TIMING ADVANCE FOR NO.1 CYLINDER, °)
Ignition timing of NO.1 cylinder is commanded by ECM. The actual ignition timing should be checked by using
the timing light.
INTAKE AIR TEMP. (°C, °F)
It is detected by intake air temp. sensor and used to determine the amount of air passing into the intake manifold
as air density varies with temperature.
MAF (MASS AIR FLOW RATE, gm/s, lb/min)
It represents total mass of air entering intake manifold which is computed based on signals from MAP sensor,
IAT sensor, TP sensor, etc.BRAKE SWIgnition switch
ONBrake pedal is depressing ON
Brake pedal is releasing OFF
BLOWER FANIgnition switch
ONBlower fan switch ON ON
Blower fan switch OFF OFF
A/C MAG CLUTCHIgnition switch
ONA/C operating ON
A/C not operating OFF SCAN TOOL DATA CONDITION REFERENCE VALUES

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 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 6-72 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P0300 Random Misfire Detected (Misfire Detected at 2 or More Cylinders)
DTC P0301 Cylinder 1 Misfire Detected
DTC P0302 Cylinder 2 Misfire Detected
DTC P0303 Cylinder 3 Misfire Detected
DTC P0304 Cylinder 4 Misfire Detected
CIRCUIT DESCRIPTION
ECM monitors crankshaft revolution speed and engine speed via the crankshaft position sensor and cylinder No.
via the camshaft position sensor. Then it calculates the change in the crankshaft revolution speed and from how
many times such change occurred in every 200 or 1000 engine revolutions, it detects occurrence of misfire.
When ECM detects a misfire (misfire rate per 200 revolutions) which can cause overheat and damage to the
three way catalytic converter, it makes the malfunction indicator lamp (MIL) flash as long as misfire occurs at
that rate.
After that, however, when the misfire rate drops, MIL remains ON until it has been judged as normal 3 times
under the same driving conditions.
Also, when ECM detects a misfire (misfire rate per 1000 revolutions) which will not cause damage to three way
catalytic converter but can cause exhaust emission to be deteriorated, it makes MIL light according to the 2 driv-
ing cycle detection logic.
1. Ignition coil assembly (for No.1 and No.4 cylinder)
2. Ignition coil assembly (for No.2 and No.3 cylinder)
3. Fuel injector
4. CKP sensor
5. CMP sensor

Downloaded from www.Manualslib.com manuals search engine ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-79
DTC P0335 (DTC No.23) Crankshaft Position (CKP) Sensor Circuit Malfunction
CIRCUIT DESCRIPTION
REFERENCE
Connect oscilloscope between terminals E19-23 of ECM connector connected to ECM and body ground and
check CKP sensor signal.
DTC CONFIRMATION PROCEDURE
1) Clear DTC and crank engine for 2 sec.
2) Select “DTC” mode on scan tool and check DTC.
DTC DETECTING CONDITION POSSIBLE CAUSE
NO CKP sensor signal for 2 seconds at engine crank-
ing.CKP sensor circuit open or short.
Signal teeth damaged.
CKP sensor malfunction, foreign material being
attached or improper installation.
ECM malfunction.
1. 10° signal [A] : Oscilloscope Waveforms [C] : Waveforms at 2000 rpm
2. 30° signal [B] : Waveforms at idle speed