2000 SUZUKI SWIFT SF310 Service Workshop Manual

6-62 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
To other sensor
Heater Ignition
switch Main
fuse
“IG COIL METER”
To ignition coilTo other sensor
DTC P0141 HEATED OXYGEN SENSOR (HO2S) HEATER CIRCUIT
MALFUNCTION (SENSOR-2)
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
DTC will set when A or B condition it met.
A. Low voltage at terminal C02-19 for specified time after engine
start or while engine running at high load.
B. High voltage at terminal C02-19 while engine running under
other than above condition.
2 driving cycle detection logic, continuous monitoring.
HO2S-2 heater circuit open or shorted
to ground

ECM (PCM) malfunction
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF once and then ON.
2) Clear DTC, start engine and warm up engine to normal operating temperature.
3) Keep it at 2000 r / min for 2 min.
4) Check pending DTC in “ON BOARD TEST” or “PENDING DTC” mode and DTC in “DTC” mode.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-63
Fig. 1 for Step 2
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check HO2S-2 Heater and Its Circuit.
1) Warm up engine to normal operating temperature.
2) Stop engine.
3) Turn ignition switch ON and check voltage at
terminal C02-19 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.
3Check 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 “Lg / B” wire terminals.
3) If OK, then check heater resistance.
Is it 11.7 – 14.3 Ω at 20C, 68F?“Lg / B” wire open or
shorted to ground or
poor connection at
C02-19. If wire and
connection are OK,
substitute a known-
good ECM (PCM)
and recheck.Replace HO2S-2.

6-64 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
Sensed
information
Exhaust
gasFuel
injector
A/F
mixtureSignal to decrease amount of fuel injection
Signal to increase amount of fuel injection
High voltage
Low voltage
INJECTORHEATED
OXYGEN
SENSOR-1
A / F mixture
becomes
richerOxygen
concentration
decreases
A / F mixture
becomes
leanerOxygen
concentration
increases ECM
(PCM)
ECM
(PCM)
Main
fuseIgnition switch“IG COIL METER”
Main relayTo other circuits
Injector resistor
To other
sensorFuel
injector
Heated oxygen sensor-1
HO2S-1
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 (TBI FOR G10) 6-65
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.
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.: –10C, 14F or higher
–Intake air temp.: 70C, 158F 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.

6-66 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
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 6E1 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 : 160 – 210 kPa, 1.6 – 2.1 kg / cm
2,
22.7 – 29.9 psi.
At specified idle speed : 90 – 140 kPa, 0.9 – 1.4 kg / cm
2,
12.8 – 20.0 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) Turn ignition switch OFF and disconnect fuel injector
connector.
2) Check for proper connection to fuel injector at each terminals.
3) If OK, then check injector resistance. See Fig. 3.
Injector resistance: 0.5 – 1.5 Ω at 20C (68F)Go to Step 6.Check injector
circuit or replace
fuel injector.
4) Connect injector, connector.
5) Check that fuel is injected out in conical shape from fuel
injector when running engine.
6) Check injector for fuel leakage after engine stop.
Fuel leakage: Less than 1 drop / min.
Is check result 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. 4.
Is vacuum felt?Check EVAP
control system
(See Section
6E1).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.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-67
Fig. 1 for Step 3 Fig. 2 for Step 4 Fig. 3 for Step 5
Fig. 4 for Step 6
1. Throttle body
2. Fuel feed hose
GoodNo good
STEPACTIONYESNO
8Check engine coolant temp. sensor for performance
(See Section 6E1).
Is it in good condition?Go to Step 9.Replace engine
coolant temp. sensor.
9Check intake air temp. sensor for performance
(See Section 6E1).
Is it in good condition?Go to Step 10.Replace intake air
temp. sensor.
10Check throttle position sensor for performance (See
Step 4 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
6E1).
Is it good condition?Substitute a known-
good ECM (PCM) and
recheck.Replace PCV valve.

Ignition coil
Igniter
Ignition switch
Main
fuse
Injector resistor
Fuel injector
Crankshaft
position sensor
Camshaft
position sensor
Ground
at engine “I / G COIL METER”
Main relay
6-68 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
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
CIRCUIT DESCRIPTION
ECM (PCM) monitors crankshaft revolution speed and engine speed via the crankshaft position sensor and cylin-
der 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 (PCM) 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 (PCM) 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
driving cycle detection logic.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-69
Below
specified value DTC DETECTING CONDITION
POSSIBLE 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 value
Engine 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
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.
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.: –10C, 14F or higher
–Intake air temp.: 70C, 158F or lower
–Engine coolant temp.: –10 – 11 0C, 14 – 230F
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”.