2000 SUZUKI SWIFT sensor

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.

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 6-81
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

6-82 ENGINE GENERAL INFORMATION AND DIAGNOSIS
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.
CAUTION:
For iridium spark plugs, do not adjust air gap or clean.
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE
DIAG. FLOW
TABLE”.

6-84 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Fig. 1 for Step 3
Fig. 2 for Step 47 Check EVAP Canister Purge Valve for Closing.
1) Disconnect purge hose from EVAP canister purge
valve.
2) Place finger against the end of EVAP canister 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
system (See Section
6E1).Go to Step 8.
8 Check MAP Sensor for performance (See DTC P0105
Diag. Flow Table).
Is it in good condition?Go to Step 9. Repair or replace.
9 Check ECT Sensor for performance (See Section 6E1).
Is it in good condition?Go to Step 10. Replace engine
coolant temp. sen-
sor.
10 Check 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 ground, ignition
system and fuel injec-
tor for intermittent
open and short.Repair or replace. Step Action Yes No
1. Fuel pressure gauge & 3 way joint
2. Fuel feed hose
1
2
1

6-86 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P0325 (DTC NO.17) KNOCK SENSOR CIRCUIT MALFUNCTION
WIRING DIAGRAM / 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
[A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
ECM
5V
RED
E11
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
C42-12 [A]
C42-25 [B]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
DTC DETECTING CONDITION POSSIBLE CAUSE
Knock sensor voltage is 3.91 V or more
or
Knock sensor voltage is 1.23 V or less“RED” circuit open or shorted to ground
Knock sensor malfunction
ECM malfunction
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Check Knock Sensor Signal.
1) With engine running, check voltage from
C42-12 terminal of ECM connector to body
ground. See Fig. 1.
Is voltage about 1.23 – 3.91 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 Check Knock Sensor Output.
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 “RED” terminal of knock sen-
sor connector to body ground. See Fig. 2.
Is it 4 – 5 V?Faulty knock sensor.
Substitute a known-good
knock sensor and
recheck.“RED” wire open, shorted
to ground circuit or poor
C42-12 (Case of TYPE A.
See NOTE) or 42-25
(Case of TYPE B. See
NOTE) connection.
If wire and connection are
OK, substitute a known-
good ECM and recheck.