ECM SUZUKI SWIFT 2000 1.G SF310 Service Service Manual

To other sensors Throttle
position
sensorTo other sensors
6-52 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
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 monitoring
TP 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:
–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.: 70 – 11 0C, 158 – 230F
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.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-53
Fig. 1 for Step 2 Fig. 2 for Step 2
Fig. 3 for Step 3
Closed
(condition “A”)Fully open
Throttle Opening
Condition “A”
Clearance between throttle lever and
throttle stop screw is less than 0.35 mm
(0.014 in.).
clearance
“1”“3”“4”
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE
DIAG. FLOW
TABLE”.
2Check TP Sensor and Its Circuit.
1) Turn ignition switch OFF and connect SUZUKI scan tool to
DLC.
2) Turn ignition switch ON and check TP sensor output
voltage when throttle valve is at idle position and fully
opened. See Fig. 1 and 2.
Dose voltage vary within specified value linearly as shown in
figure?If voltmeter was
used, check
terminal C01-6 for
poor connection.
If OK, substitute a
known-good ECM
(PCM) and
recheck.Go to Step 3.
3Check TP Sensor.
1) Turn ignition switch OFF.
2) Disconnect TP sensor connector.
3) Check for proper connection to TP sensor at each terminal.
4) If OK, then measure resistance between terminals and
check if each measured value is as specified below.
See Fig. 3.
Between 1 and 4: 2.87 – 5.33 kΩ
Between 1 and 3: 100 Ω – 20 kΩ, varying according to
throttle valve opening.
Are measured values as specified?High resistance in
“Lg”, “Lg / W” or
“G” circuit.
If wire and
connection are
OK, substitute a
known-good ECM
(PCM) and
recheck.Replace TP
sensor.

To generatorTo other sensor
Heater Ignition
switch Main
fuse
“IG COIL METER”
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-57
DTC P0135 HEATED OXYGEN SENSOR (HO2S) HEATER CIRCUIT
MALFUNCTION (SENSOR-1)
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
DTC will set when A or B condition is met.
A:

Low voltage at terminal C01-8 when engine is
running at high load.
B:

High voltage at terminal C01-8 when engine is
running under condition other than above.
2 driving cycle detection logic, Continuous
monitoring.
HO2S-1 heater circuit open or shorted to ground

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.
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON, start engine and keep it at idle for 1 min.
3) Start vehicle and depress accelerator pedal fully for 5 sec. or longer.
4) Stop vehicle.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.

6-58 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
Fig. 1 for Step 2 Fig. 2 for Step 3
C01-8
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check Heater for Operation.
1) Check voltage at terminal C01-8. See Fig. 1.
2) Warm up engine to normal operating temperature.
3) Stop engine.
4) Turn ignition switch ON and Check voltage atIntermittent trouble
Check for intermittent
referring to
“Intermittent and
Poor Connection”Go to Step 3.
terminal C01-8. See Fig. 1. Voltage should be
over 10 V.
5) Start engine, run it at idle and check voltage at the
same terminal. Voltage should be below 1.9 V.
Are check results are specified?in Section 0A.
3Check Heater of Sensor-1.
1) Disconnect HO2S-1 coupler with ignition switch
OFF.
2) Check for proper connection to HO2S-1 at “B/W”
and “P/B” wire terminals.
3) If OK, then check heater resistance. See Fig. 2.
Is it 11.7 – 14.3 Ω at 20C, 68F?“P/B” wire open or
shorted to ground or
poor connection at
C01-8. If wire and
connection are OK,
substitute a
known-good ECM
(PCM) and recheck.Replace HO2S-1.

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) 6-67
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) 6-71
1. Throttle body
2. Fuel feed hose
GoodNo good1. Injector connector
STEPACTIONYESNO
6Check PCV valve for clogging (See Section 6E1).
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. 5.
Is vacuum felt?Check EVAP
control system
(See Section 6E1).Go to Step 8.
8Check intake manifold pressure sensor for performance
(See Section 6E1).
Is it in good condition?Go to Step 9.Repair or replace.
9Check engine coolant temp. sensor for performance
(See Section 6E1).
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 6A).
–Valve lash (See Section 6A).
–Valve timing (Timing belt installation. See Section 6A).
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 7