2000 SUZUKI SWIFT engine

6-74 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P0141 HEATED OXYGEN SENSOR (HO2S) HEATER CIRCUIT MALFUNC-
TION (SENSOR-2)
WIRING DIAGRAM / CIRCUIT DESCRIPTION
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.
ECM
BLK/WHT
PNK/BLU
C41-4 IG1
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
DTC DETECTING CONDITION POSSIBLE CAUSE
DTC will set when any one of the following conditions is
met.
Low voltage at terminal C41-4 for specified time after
engine start or while engine running at high load.
High voltage at terminal C41-4 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 malfunction

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-75
INSPECTION
Fig. 1 for Step 2Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” per-
formed?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 C41-4 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 of Sensor-2.
1) Disconnect HO2S-2 coupler with ignition
switch OFF.
2) Check for proper connection to HO2S-2 at
“BLK/WHT” and “PNK/BLU” wire terminals.
3) If OK, then check heater resistance.
Is it 12.0 – 14.3 Ω at 20°C, 68°F?“PNK/BLU” wire open or
shorted to ground or poor
connection at C41-4. If
wire and connection are
OK, substitute a known-
good ECM and recheck.Replace HO2S-2.

6-76 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P0171 FUEL SYSTEM TOO LEAN
DTC P0172 FUEL SYSTEM TOO RICH
WIRING DIAGRAM / CIRCUIT DESCRIPTION
1. Injector [a] : Signal to decrease amount of fuel injection [f] : A/F mixture becomes leaner
2. HO2S-1 [b] : Signal to increase amount of fuel injection [g] : Oxygen concentration decreases
3. WU-TWC (Warm up-three way catalytic convec-
tor)[c] : High voltage [h] : Oxygen concentration increases
4. Sensed information [d] : Low voltage
5. ECM [e] : A/F mixture becomes richer
[a]
[b]
[f] [e] [g][d]
[h][c]
1
2 5
1
2
2
3
54
+BECM
C42-9
C42-21
C42-8 C42-31
C42-1
BLU/YEL
BLU/WHT
BLU/RED
BLK/ORN
C42-3
BLK/ORN BLU/ORN
WHT
ORNC42-10C42-13
E111
DTC DETECTING CONDITION POSSIBLE CAUSE
When one of the following conditions 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%)
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 6-77
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” per-
formed?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.
2) Warm up engine to normal operating tem-
perature 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 cir-
cuit check).
4 Check 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 :
270 – 310 kPa, 2.7 – 3.1 kg/cm
2, 38.4 –
44.0 psi.
At specified idle speed :
270 – 310 kPa, 2.7 – 3.1 kg/cm
2, 38.4 –
44.0 psi.
Is measured value as specified?Go to Step 5. Go to Diag. Flow Table B-
3 Fuel Pressure Check.

6-78 ENGINE GENERAL INFORMATION AND DIAGNOSIS
5 Check Fuel Injectors and Circuit.
1) Using sound scope (1) or such, check oper-
ating 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 cou-
pler) 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.
4) If OK, then check injector resistance.
Injector Resistance : 11.3 – 13.8 ohm at
20°C (68°F)
5) Carry out steps 1) and 3) on each injector.
6) Check each injector for injected fuel volume
(1) referring to Section 6E1. See Fig. 5.
Injected Fuel Volume : 43 – 47 cc/15 sec
1.45/1.51 – 1.58/1.65 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) satisfac-
tory?Go to Step 6. Check injector circuit or
replace fuel injector(s).
6 Check EVAP Canister Purge Valve.
1) Disconnect purge hose from EVAP canister
purge valve.
2) Place finger against the end of EVAP canis-
ter purge valve.
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 sys-
tem (See Section 6E1).Go to Step 7.
7 Check Intake manifold absolute pressure sen-
sor for performance (See DTC P0105 (No.11)
Diag. Flow Table).
Is it in good condition?Go to Step 8. Repair or replace.
8 Check Engine Coolant Temp. Sensor for perfor-
mance (See Section 6E1).
Is it in good condition?Go to Step 9. Replace engine coolant
temp. sensor.
9 Check Intake Air Temp. Sensor for perfor-
mance (See Section 6E1).
Is it in good condition?Go to Step 10. Replace intake air temp.
sensor.
10 Check 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.
11 Check PCV Valve for valve clogging (See Sec-
tion 6E1).
Is it good condition?Substitute a known-good
ECM and recheck.Replace PCV valve. Step Action Yes No

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-79
Fig. 1 for Step 3
Fig. 2 for Step 4
Fig. 3 for Step 5
Fig. 4 for Step 5

6-80 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Fig. 5 for Step 5
Fig. 6 for Step 6

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-81
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
WIRING DIAGRAM
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 No. 1
2. Ignition coil No. 2
3. CKP sensor
4. CMP sensor
5. Fuel injector
C42-20
C42-19
ECM
IG1
5V
5V
GRN/YEL
BLK/WHT
GRN/WHT
IG1 2
+B
C42-9
C42-21
C42-8
C42-23 C42-31 BLU/YEL
BLU/WHT
BLU/RED
BLU/ORN
YEL/BLK
5V
C42-11
RED/YEL
5V
BLK/RED
3
45
5
1