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 6-20 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Visual inspection
Visually check following parts and systems.
INSPECTION ITEM REFERRING SECTION
Engine oil – level, leakage Section 0B
Engine coolant – level, leakage Section 0B
Fuel – level, leakage Section 0B
A/T fluid – level, leakage Section 0B
Air cleaner element – dirt, clogging Section 0B
Battery – fluid level, corrosion of terminal
Water pump belt – tension, damage Section 0B
Throttle cable – play, installation
Section 6E Vacuum hoses of air intake system – disconnection, looseness,
deterioration, bend
Connectors of electric wire harness – disconnection, friction
Fuses – burning Section 8
Parts – installation, bolt – looseness
Parts – deformation
Other parts that can be checked visually
Also check following items at engine start, if possible
Malfunction indicator lamp – operation Section 6
Charge warning lamp – operation Section 6H
Engine oil pressure warning lamp – operation Section 8 (Section 6 for pressure check)
Engine coolant temp. meter – operation Section 8
Fuel level meter – operation Section 8
Tachometer, if equipped – operation
Abnormal air being inhaled from air intake system
Exhaust system – leakage of exhaust gas, noise
Other parts that can be checked visually
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
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THROTTLE POS (ABSOLUTE THROTTLE POSITION, %)
When throttle position sensor is fully closed position, throttle opening is indicated as 0% and 100% full open
position.
OXYGEN SENSOR B1 S1 (HEATED OXYGEN SENSOR-1, V)
It indicates output voltage of HO2S-1 installed on exhaust manifold (pre-catalyst).
OXYGEN SENSOR B1 S2 (HEATED OXYGEN SENSOR-2, V)
It indicates output voltage of HO2S-2 installed on exhaust pipe (post-catalyst). It is used to detect catalyst dete-
rioration.
DESIRED IDLE (DESIRED IDLE SPEED, rpm)
The Desired Idle Speed is an ECM internal parameter which indicates the ECM requested idle. If the engine is
not running, this number is not valid.
TP SENSOR VOLT (THROTTLE POSITION SENSOR OUTPUT VOLTAGE, V)
The Throttle Position Sensor reading provides throttle valve opening information in the form of voltage.
INJ PULSE WIDTH (FUEL INJECTION PULSE WIDTH, msec.)
This parameter indicates time of the injector drive (valve opening) pulse which is output from ECM (but injector
drive time of NO.1 cylinder for multiport fuel injection).
IAC FLOW DUTY (IDLE AIR (SPEED) CONTROL DUTY, %)
This parameter indicates current flow time rate within a certain set cycle of IAC valve (valve opening rate) which
controls the amount of bypass air (idle speed).
TOTAL FUEL TRIM (%)
The value of Total Fuel Trim is obtained by putting values of short Term Fuel Trim and Long Term Fuel Trim
together. This value indicates how much correction is necessary to keep the air / fuel mixture stoichiometrical.
BATTERY VOLTAGE (V)
This parameter indicates battery positive voltage inputted from main relay to ECM.
CANIST PURGE DUTY (EVAP CANISTER PURGE FLOW DUTY, %)
This parameter indicates valve ON (valve open) time rate within a certain set cycle of EVAP purge solenoid
valve which controls the amount of EVAP purge.
0% means that the purge valve is completely closed while 100% is a fully open valve.
CLOSED THROTTLE POSITION (ON / OFF)
This parameter will read ON when throttle valve is fully closed, or OFF when the throttle is not fully closed.
FUEL CUT (ON / OFF)
ON : Fuel being cut (output signal to injector is stopped)
OFF : Fuel not being cut
A/C CONDENSER FAN (A/C CONDENSER FAN RELAY, ON / OFF)
ON : Command for condenser fan relay operation being output.
OFF : Command for relay operation not being output.
ELECTRIC LOAD (ON / OFF)
ON : Headlight, small light, heater fan or rear window defogger ON signal inputted.
OFF : Above electric loads all turned OFF.
A/C SWITCH (ON / OFF)
ON : Command for A/C operation being output from ECM to A/C amplifier.
OFF : Command for A/C operation not being output.
Downloaded from www.Manualslib.com manuals search engine 6-64 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P0136 Heated Oxygen Sensor (HO2S) Circuit Malfunction (Sensor-2)
CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
Clear DTC with ignition switch ON, check vehicle and environmental condition for :
–Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Ambient temp. : –10 °C, 14 °F or higher
–Intake air temp. : 70 °C, 158 °F or lower
–No exhaust gas leakage and loose connection
2) Warm up engine to normal operating temperature.
3) Drive vehicle under usual driving condition for 5 min. and check HO2S-2 output voltage and “short term fuel
trim” with “Data List” mode on scan tool, and write it down.
4) Stop vehicle (don’t turn ignition switch OFF).
5) Increase vehicle speed to higher than 20 mph, 32 km/h and then stop vehicle.
1. Heated oxygen sensor-2 (HO2S-2) [A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
NOTE:
For TYPE A and TYPE B, refer to the NOTE in “ECM Terminal Voltage Values Table” for applicable
model.
DTC DETECTING CONDITION POSSIBLE CAUSE
Engine is warmed up and HO2S-2 voltage is 4.5 V or more.
(circuit open)
✱
✱✱ ✱2 driving cycle detection logic, monitoring once / 1 driving.Exhaust gas leakage
“W” or “B/Bl” circuit open or short
Heated oxygen sensor-2 malfunction
Fuel system malfunction
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester, on a level road.
Downloaded from www.Manualslib.com manuals search engine ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-65
6) Repeat above steps 5) 4 times.
7) Increase vehicle speed to about 50 mph (80 km/h) in 3rd gear or 2 range.
8) Release accelerator pedal and with engine brake applied, keep vehicle coasting (fuel cut condition) for
10sec. or more.
9) Stop vehicle (don’t turn ignition switch OFF) and run engine at idle for 2 min. After this step 9), if “Oxygen
Sensor Monitoring TEST COMPLETED” is displayed in “READINESS TESTS” mode and DTC is not dis-
played in “DTC” mode, confirmation test is completed.
If “TEST NOT COMPLTD” is still being displayed, proceed to next step 10).
10) Drive vehicle under usual driving condition for 10 min. (or vehicle is at a stop and run engine at idle for 10
min. or longer)
11) Stop vehicle (don’t turn ignition switch OFF). Confirm test results according to “Test Result Confirmation
Flow Table” in “DTC CONFIRMATION PROCEDURE” of DTC P0420.
INSPECTION
*Usual driving : Driving at 30 – 40 mph, 50 – 60 km/h including short stop according to traffic signal. (under driving condition other than high-load, high-engine
speed, rapid accelerating and decelerating)
Step Action Yes No
1Was “Engine Diag. Flow Table” performed? Go to Step 2. Go to “Engine Diag. Flow
Table”.
2 Check exhaust system for leakage, loose con-
nection and damage.
Is it good condition?Go to Step 3. Repair or replace.
3 Check HO2S-2 and Its Circuit.
Was HO2S-2 output voltage indicated on scan
tool in step 3) of DTC confirmation test less
than 1.275 V?Go to Step 4.“B/Bl” or “W” circuit open
or HO2S-2 malfunction.
4 Check Short Term Fuel Trim.
Did short term fuel trim very within –20 – + 20%
range in step 3) of DTC confirmation test?Check “W” and “B/Bl” wire
for open and short, and
connection for poor con-
nection. If wire and con-
nection are OK, replace
HO2S-2.Check fuel system. Go to
DTC P0171 / P0172 Diag.
Flow Table.
Downloaded from www.Manualslib.com manuals search engine 6-68 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P0171 Fuel System Too Lean
DTC P0172 Fuel System Too Rich
CIRCUIT DESCRIPTION
[a] : Signal to decrease amount of fuel injection [d] : A/F mixture becomes richer
(Oxygen concentration decreases)1. Injector
[b] : Signal to increase amount of fuel injection [e] : High voltage 2. Heated oxygen sensor-1 (HO2S-1)
[c] : A/F mixture becomes leaner
(Oxygen concentration increases)[f] : Low voltage
DTC DETECTING CONDITION POSSIBLE CAUSE
When following condition occurs while engine running
under closed loop condition.
–Air / fuel ratio too lean
(Total fuel trim (short and long terms added) is more
than 30%)
or
–Air / fuel ratio too rich
(Total fuel trim is less than –30%)
✱
✱✱ ✱2 driving cycle detection logic, continuous monitoring.Vacuum leaks (air drawn in).
Exhaust gas leakage.
Heated oxygen sensor-1 circuit malfunction.
Fuel pressure out of specification.
Fuel injector malfunction (clogged or leakage).
MAP sensor poor performance.
ECT sensor poor performance.
IAT sensor poor performance.
TP sensor poor performance.
EVAP control system malfunction.
PCV valve malfunction.
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