6-1-52 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
Throttle
position
sensorTo other sensors
To other sensors
DTC P0121 THROTTLE POSITION CIRCUIT RANGE / PERFORMANCE
PROBLEM
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
After engine warmed up.
While vehicle running at specified engine speed.
No change in intake manifold pressure (constant throttle opening)
Difference between actual throttle opening (detected from TP sensor)
and opening calculated by ECM (PCM) (Obtained on the basis of
engine speed and intake manifold pressure) in larger than specified
value.
2 driving cycle detection logic, continuous monitoringTP sensor malfunction
High resistance in the circuit
ECM (PCM) malfunction
DTC CONFIRMATION PROCEDURE
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
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.
1) Turn ignition switch OFF. Clear DTC with ignition switch ON, check vehicle and environmental condition for:
–Indication of fuel level meter in combination meter: 1 / 4 or more
–Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Intake air temp.: between –10C and 80C (14F and 176F)
–Engine coolant temp.: 70C, 158F or higher
2) Warm up engine to normal operating temperature.
3) Increase vehicle speed to 30 – 40 mph, 50 – 60 km / h in 3rd gear or “D” range and hold throttle valve at that
opening position for 1 min.
4) Stop vehicle.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
6-1-54 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
Ignition
switch
Main
fuse
To HO2S-2 heaterTo other sensor
Heater Fuse box
DTC P0130 HEATED OXYGEN SENSOR (HO2S) CIRCUIT MALFUNCTION
(SENSOR-1)
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
When running at idle speed after engine warmed up
and running at specified vehicle speed, HO2S-1
output voltage does not go 0.3 V below or over
0.6 V.
2 driving cycle detection logic, Monitoring once / 1
driving.Heated oxygen sensor-1 malfunction
“G” or “R” circuit open (poor connection) or short
DTC CONFIRMATION PROCEDURE
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
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.
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)
–Intake air temp.: between –10C and 80C (14F and 176F)
2) Warm up engine to normal operating temperature.
3) Drive vehicle at 38 – 50 mph, 60 – 80 km / h for 2 min.
4) Stop vehicle and run engine at idle for 2 min.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-61
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)1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11)and 50 mph
(80 km / h)
Above 20 mph
(32 km / h) Usual driving
DTC CONFIRMATION PROCEDURE
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
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.
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)
–Intake air temp.: –10C, 14F or higher
–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.
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 displayed 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.
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-65
Ignition
switch
Main
fuseMain relay
To ignition
switchTo other sensor Relay boxNo.1 injector
No.2 injector
No.3 injector
No.4 injector Fuse box
Signal to decrease amount of fuel injection
Signal to increase amount of fuel injection
High voltage
Low voltage
A / F mixture
becomes
richerOxygen
concentration
decreases
A / F mixture Oxygen
Fuel injectorSensed
information
A / F mixture
Exhaust gas
becomes
leanerconcentration
increases
DTC P0171 FUEL SYSTEM TOO LEAN
DTC P0172 FUEL SYSTEM TOO RICH
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE 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.
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-67
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE
DIAG. FLOW
TABLE”.
2Is there DTC(s) other than fuel system
(DTC P0171 / P0172)?Go to applicable
DTC Diag. Flow
Table.Go to Step 3.
3Check HO2S-1 Output Voltage.
1) Connect scan tool to DLC with ignition switch OFF.
2) Warm up engine to normal operating temperature 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). See Fig. 1.
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 circuit
check).
4Check Fuel Pressure (Refer to section 6E2 for details).
1) Release fuel pressure from fuel feed line.
2) Install fuel pressure gauge.
3) Check fuel pressure. See Fig. 2.
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 : 200 – 240 kPa, 2.0 – 2.4 kg / cm
2,
28.4 – 34.1 psi.
Is measured value as specified?
Go to Step 5.Go to Diag. Flow
Table B-3 Fuel
Pressure Check.
5Check Fuel Injectors and Circuit.
1) Using sound scope (1) or such, check operating sound of
each injector (2) when engine is running. Cycle of operating
sound should vary according to engine speed. See Fig. 3.
If no sound or an unusual sound is heard, check injector
circuit (wire or coupler) or injector.
2) Turn ignition switch OFF and disconnect a fuel injector
connector.
3) Check for proper connection to fuel injector at each terminal.
See Fig. 4.Go to Step 6.Check injector
circuit or replace
fuel injector(s).
4) If OK, then check injector resistance.
Injector Resistance: 12 – 13 ohm at 20C (68F)
5) Carry out steps 1) and 3) on each injector.
6) Check each injector for injected fuel volume referring to
Section 6E2. See Fig. 5.
Injected Fuel Volume: 38 – 48 cc / 15 sec 1.28 /
1.34 – 1.62 / 1.69 US / Imp.oz / 15 sec)
7) Check each injector for fuel leakage after injector closed.
Fuel Leakage: Less than 1 drop / min.
Is check result in step 1) and 3) to 7) satisfactory?
6Check EVAP Canister Purge Valve.
1) Disconnect purge hose (1) from EVAP canister.
2) Place finger against the end of disconnected hose.
3) Check that vacuum is not felt there when engine is cool and
running at idle. See Fig. 6.
Is vacuum felt?Check EVAP
control system
(See Section
6E2).Go to Step 7.
7Check intake manifold absolute pressure sensor for
performance (See DTC P0105 Diag. Flow Table).
Is it in good condition?Go to Step 8.Repair or
replace.
6-1-68 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
Fig. 1 for Step 3 Fig. 2 for Step 4 Fig. 3 for Step 5
Fig. 4 for Step 5 Fig. 5 for Step 5 Fig. 6 for Step 6
1. Fuel delivery pipe
2. Fuel feed hose
3. Fuel pressure gauge &
3 way joint
STEPACTIONYESNO
8Check engine coolant temp. sensor for performance
(See Section 6E2).
Is it in good condition?Go to Step 9.Replace engine
coolant temp. sensor.
9Check intake air temp. sensor for performance
(See Section 6E2).
Is it in good condition?Go to Step 10.Replace intake air
temp. sensor.
10Check throttle position sensor for performance (See
Step 3 of DTC P0121 Diag. Flow Table).
Is it in good condition?Go to Step 11.Replace throttle
position sensor.
11Check PCV valve for valve clogging
(See Section 6E2).
Is it good condition?Substitute a known-
good ECM (PCM) and
recheck.Replace PCV valve.
Below
specified value
6-1-70 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
1. CKP sensor signal
2. No.1 fuel injector signal
3. No.3 fuel injector signal
4. Fuel injection time
Display of fuel injection signal using oscilloscope
Waveforms at specified idle speed5ms/Div
DTC DETECTING CONDITIONPOSSIBLE CAUSE
Engine under other than high revolution condition
Not on rough road
Engine speed changing rate
Manifold absolute
pressure changing rate
Throttle opening changing rate
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
DTC CONFIRMATION PROCEDURE
NOTE:
Among different types of random misfire, if misfire occurs at cylinders 1 and 4 or cylinders 3 and 2 simulta-
neously, it may not possible to reconfirm DTC by using the following DTC confirmation procedure. When
diagnosing the trouble of DTC P0300 (Random misfire detected) of the engine which is apparently misfir-
ing, even if DTC P0300 cannot be reconfirmed by using the following DTC confirmation procedure, pro-
ceed 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 accident
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.
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)
–Intake air temp.: between –10C and 80C (14F and 176F)
–Engine coolant temp.: –10C, 14F or higher
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 analy-
sis” and “Freeze frame data check”.
Reference
6-1-72 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
Disconnect connectors when checking plugs
for spark1. Fuel delivery pipe
2. Fuel feed hose
3. FUel pressure
gauge & 3 way joint
STEPACTIONYESNO
6Check PCV valve for clogging (See Section 6E2).
Is it in good condition?Go to Step 7.Replace PCV valve.
7Check EVAP Canister Purge Valve for Closing.
1) Disconnect purge hose (1) from EVAP canister.
2) Place finger against the end of disconnected hose.
3) Check that vacuum is not felt there, when engine is
cool and running at idle. See Fig. 7.
Is vacuum felt?Check EVAP
control system
(See Section 6E2).Go to Step 8.
8Check intake manifold pressure sensor for performance
(See DTC P0105 Diag. Flow Table).
Is it in good condition?Go to Step 9.Repair or replace.
9Check engine coolant temp. sensor for performance
(See Section 6E2).
Is it in good condition?Go to Step 10.Replace engine
coolant temp.
sensor.
10Check parts or system which can cause engine rough
idle or poor performance.
–Engine compression (See Section 6A1).
–Valve lash (See Section 6A1).
–Valve timing (Timing belt installation. See Section 6A1).
Are they in good condition?Check wire harness
and connection of
ECM (PCM) ground,
ignition system and
fuel injector for
intermittent open
and short.Repair or replace.
Fig. 1 for Step 3 Fig. 2 for Step 3 Fig. 3 for Step 4
Fig. 4 for Step 5 Fig. 5 for Step 4 Fig. 6 for Step 5
Fig. 7 for Step 7