Downloaded from www.Manualslib.com manuals search engine ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-67
INSPECTION
Fig. 1 for Step 2Step Action Yes No
1Was “Engine Diag. Flow Table” performed? Go to Step 2. Go to “Engine Diag. Flow
Table”.
2 Check HO2S-2 Heater and Its Circuit.
1) Warm up engine to normal operating tem-
perature.
2) Stop engine.
3) Turn ignition switch ON and check voltage at
terminal E18-4. See Fig. 1. Voltage should
be over 10 V.
4) Start engine, run it at idle and check voltage
at the same terminal after 1 min. from
engine start.
Voltage should be below 1.9 V.
Are check result as specified?Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection” in
Section 0A.Go to Step 3.
3 Check Heater or Sensor-2.
1) Disconnect HO2S-2 coupler with ignition
switch OFF.
2) Check for proper connection to HO2S-2 at
“B/W” and “R/Bl” wire terminals.
3) If OK, then check heater for resistance.
Is it 11.7 – 14.3 Ω at 20 °C, 68 °F?“R/Bl” wire open or
shorted to ground or poor
connection at E18-4. If
wire and connection are
OK, substitute a known-
good ECM and recheck.Replace HO2S-2.
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DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) 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
4) Start engine and drive vehicle under usual driving condition (described in DTC confirmation procedure of
DTC P0136) for 5 min. or longer and until engine is warmed up to normal operating temperature.
5) Keep vehicle speed at 30 – 40 mph, 50 – 60 km/h in 5th gear or “D” range for 5 min. or more.
6) Stop vehicle (do not turn ignition switch OFF).
7) Check pending DTC in “ON BOARD TEST” or “PENDING DTC” mode and DTC in “DTC” mode.
INSPECTION
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.
Step Action Yes No
1Was “Engine Diag. Flow Table” performed? Go to Step 2. Go to “Engine Diag.
Flow Table”.
2 Is there DTC(s) other than fuel system
(DTC P0171 / P0172)?Go to applicable DTC
Diag. Flow Table.Go to Step 3.
3 Check HO2S-1 Output Voltage.
1) Connect scan tool to DLC with ignition switch
OFF. See Fig. 1.
2) Warm up engine to normal operating tempera-
ture and keep it at 2000 r/min. for 60 sec.
3) Repeat racing engine (Repeat depressing
accelerator pedal 5 to 6 times continuously and
take foot off from pedal to enrich and enlean
A/F mixture).
Does HO2S-1 output voltage deflect between
below 0.3 V and over 0.6 V repeatedly?Go to Step 4. Go to DTC P0130 Diag.
Flow Table (HO2S-1 cir-
cuit check).
4 Check Fuel Pressure (Refer to Section 6E for
details).
1) Release fuel pressure from fuel feed line.
2) Install fuel pressure gauge. See Fig. 2.
3) Check fuel pressure.
Fuel pressure specification
With fuel pump operating and engine at stop :
270 – 310 kPa, 2.7 – 3.1 kg/cm
2, 38.4 – 44.0 psi.
At specified idle speed :
210 – 260 kPa, 2.1 – 2.6 kg/cm
2, 29.8 – 37.0 psi.
Is measured value as specified?Go to Step 5. Go to Diag. Flow Table
B-3 Fuel Pressure
Check.
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DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) 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
–Engine coolant temp. : – 10 – 110 °C, 14 – 230 °F
4) Start engine and keep it at idle for 2 min. or more.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
6) If DTC is not detected at idle, consult usual driving based on information obtained in “Customer complaint
analysis” and “Freeze frame data check”.
INSPECTION
DTC DETECTING CONDITION POSSIBLE CAUSE
Engine under other than high revolution condition
Not on rough road
Engine speed changing rate (below specified value)
Manifold absolute pressure changing rate (below
specified value)
Throttle opening changing rate (below specified
value)
Misfire rate per 200 or 1000 engine revolutions (how
much and how often crankshaft revolution speed
changes) is higher than specified valueEngine overheating
Vacuum leaks (air inhaling) from air intake system
Ignition system malfunction (spark plug(s), high-
tension cord(s), ignition coil assembly)
Fuel pressure out of specification
Fuel injector malfunction (clogged or leakage)
Engine compression out of specification
Valve lash (clearance) out of specification
Manifold absolute pressure sensor malfunction
Engine coolant temp. sensor malfunction
PCV valve malfunction
EVAP control system malfunction
EGR system malfunction
NOTE:
Among different types of random misfire, if misfire occurs at cylinders 1 and 4 or cylinders 3 and 2
simultaneously, it may not possible to reconfirm DTC by using the following DTC confirmation proce-
dure. When diagnosing the trouble of DTC P0300 (Random misfire detected) of the engine which is
apparently misfiring, even if DTC P0300 cannot be reconfirmed by using the following DTC confirma-
tion procedure, proceed to the following Diag. Flow Table.
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.
Step Action Yes No
1Was “Engine Diag. Flow Table” performed? Go to Step 2. Go to “Engine
Diag. Flow Table”.
2 Is there DTC other than Fuel system (DTC P0171/
P0172) and misfire (DTC P0300 – P0304)?Go to applicable DTC
Diag. Flow Table.Go to Step 3.
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DTC P0325 (DTC No.17) Knock Sensor Circuit Malfunction
CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
1) Clear DTC, start engine and keep it at idle for 1 min.
2) Select “DTC” mode on scan tool and check DTC.
INSPECTION
DTC DETECTING CONDITION POSSIBLE CAUSE
Knock sensor voltage is 3.91 V or more
Knock sensor voltage is 1.23 V or less“W” circuit open or shorted to ground
Knock sensor malfunction
ECM malfunction
Step Action Yes No
1Was “Engine Diag. Flow Table” performed? Go to Step 2. Go to “Engine Diag. Flow
Table”.
2 1) With engine running, check voltage from
“E19-25” terminal of ECM connector to
body ground. See Fig. 1.
2) Is voltage about 1.25 – 3.75 V?Knock sensor and its cir-
cuit are in good condition.
Intermittent trouble or
faulty ECM.
Recheck, referring to
“Intermittent Trouble” in
Section 0A.Go to Step 3.
3 1) Stop engine.
2) With ignition switch at OFF position, discon-
nect knock sensor connector.
3) With ignition switch at ON position, check
voltage from “W” to body ground terminal of
knock sensor connector. See Fig. 2.
Is it 4 – 5 V?Faulty knock sensor.
Substitute a known-good
knock sensor and
recheck.“W” wire open, shorted to
ground circuit or poor
“E19-25” connection.
If wire and connection are
OK, substitute a known-
good ECM and recheck.
Downloaded from www.Manualslib.com manuals search engine 6-82 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P0340 (DTC No.15) Camshaft Position (CMP) Sensor Circuit Malfunction
CIRCUIT DESCRIPTION
REFERENCE
Connect oscilloscope between terminals E19-11 of ECM connector connected to ECM and body ground and
check CMP sensor signal.
DTC CONFIRMATION PROCEDURE
1) Clear DTC.
2) Start engine and keep it at idle for 1 min.
3) Select “DTC” mode on scan tool and check DTC.
DTC DETECTING CONDITION POSSIBLE CAUSE
The number of CMP sensor signal pulses is incor-
rect during 8 revolution of crankshaft.CMP sensor circuit open or short.
Signal rotor teeth damaged.
CMP sensor malfunction, foreign material being
attached or improper installation.
ECM malfunction.
CMP sensor phase lag.
1. No.1 cylinder 3. No.3 cylinder [A] : Oscilloscope Waveforms [C] : CKP sensor waveform
2. No.2 cylinder 4. No.4 cylinder [B] : Waveforms at specified idle speed [D] : CMP sensor waveform
Downloaded from www.Manualslib.com manuals search engine 6-86 ENGINE GENERAL INFORMATION AND DIAGNOSIS
2) Start engine and warm it up to normal operating temperature (70 – 110 °C, 158 – 230 °F) and run it at idle
for 5 min.
3) Increase vehicle speed to 50 – 55 mph, 80 – 88 km/h in 5th gear or in “D” range.
4) Hold throttle valve at that opening position for 2 min. or longer.
5) Increase engine speed to 4000 r/min. in 3rd gear or in “2” range.
6) Release accelerator pedal and with engine brake applied, keep vehicle coasting (fuel cut condition) till
engine speed reaches 1500 r/min.
7) Stop vehicle (don’t turn ignition switch OFF) and confirm test results according to following “Test Result Con-
firmation Flow Table.”
Test Result Confirmation Flow Table
INSPECTION
Step Action Yes No
1 Check DTC in “DTC” mode and pending DTC in
“ON BOARD TEST”.
Is DTC or pending DTC displayed?Proceed to applicable
DTC flow table.Go to Step 2.
2 Set scan tool to “READINESS TESTS” mode
and check if testing has been completed.
Is test completed?No DTC is detected.
(Confirmation test is com-
pleted)Repeat DTC confirmation
procedure.
Step Action Yes No
1Was “Engine Diag. Flow Table” performed? Go to Step 2. Go to “Engine Diag. Flow
Table”.
2 1) Turn ignition switch ON.
2) Does EGR stepper motor operation for 0.6
second after ignition switch OFF?Go to Step 3. Go to Step 6.
3 With ignition switch at OFF, check voltage
between E19-28, 17, 29, 18 terminals of ECM
and body ground. See Fig. 2.
Is voltage about 0 V?Go to Step 4. Go to Step 8.
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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
–Engine coolant temp. : 70 – 110 °C, 158 – 230 °F
2) Start engine and drive vehicle at 35 – 45 mph, 55 – 65 km/h for 8 min. or longer.
While this driving, if “Catalyst Monitoring TEST COMPLETED” is displayed in “READINESS TESTS” mode
and DTC is not displayed in “DTC” mode, confirmation test is completed.
If “TEST NOT COMPLTD” is still being displayed, continue test driving.
3) Decrease vehicle speed at 30 – 40 mph, 50 – 60 km/h, and hold throttle valve at that opening position for 2
min. and confirm that short term fuel trim vary within – 20% – +20% range.
4) Stop vehicle (do not turn ignition switch OFF) and confirm test results according to following “Test Result
Confirmation Flow Table”. DTC DETECTING CONDITION POSSIBLE CAUSE
While vehicle running at constant speed under other than
high load.
Time from rich or lean switching command is output till HO2S-
2 output voltage crosses 0.45 V less than specified value.
✱
✱✱ ✱2 driving cycle detection logic, monitoring once / 1 driving.Exhaust gas leak
Three way catalytic converter malfunction
Fuel system malfunction
HO2S-2 malfunction
HO2S-1 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 6-92 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P0481 A/C Condenser Fan Control Circuit Malfunction
CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Start engine and then turn both A/C switch and heater blower switch ON for 2 sec or more.
4) Run engine at idle for 5 sec or more which A/C switch and heater blower switch OFF.
5) Check DTC and pending DTC.
1. Ignition switch 3. A/C condenser fan relay 5. A/C condenser fan 7. Fuse box
DTC DETECTING CONDITION POSSIBLE CAUSE
Low voltage at terminal E18-18 when ECM doesn’t out-
put A/C ON signal to A/C amplifier or when engine cool-
ant temp. is not 110 °C (230 °F) or more.
✱
✱✱ ✱2 driving cycle detection logic, continuous monitoring.“P/B” or “Lg” circuit open or short
Condenser fan motor relay malfunction
ECM malfunction