ECM ground circuit SUZUKI SWIFT 2006 2.G Service Service Manual

Downloaded from www.Manualslib.com manuals search engine 1A-98 Engine General Information and Diagnosis:
DTC P0171 / P0172: Fuel System Too Lean / RichS7RS0B1104036
DTC Detecting Condition and Trouble Area
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 by 2 persons, a driver and a tester, on a level road.

NOTE
Check to make sure that following conditions ar e satisfied when using this “DTC Confirmation
Procedure”.
• Intake air temperature at engine start: –10 °C (14 ° F) to 80 °C (176 °F)
• Intake air temperature: –10 °C (14 °F) to 70 °C (158 °F)
• Engine coolant temperature: 40 °C (104 °F) to 120 °C (248 °F)
• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)

3 Wire circuit check
1) Turn OFF ignition switch.
2) Remove ECM from its br acket with ECM connectors
connected.
3) Measure resistance between “BRN” wire terminal of HO2S-2 connector and “C37-11” terminal of ECM
connector.
Is resistance less than 5
Ω? Go to Step 4. “BRN” wire is high
resistance circuit or
open circuit. Poor “C37-
11” terminal connection.
If they are OK,
substitute a known-
good ECM and recheck.
4 HO2S-2 signal circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure voltage between “BRN” wire terminal of HO2S- 2 connector and vehicle body ground.
Is voltage 0 V? Go to Step 5. “BRN” wire is shorted to
other circuit.
5 HO2S-2 heater circuit check
1) Check HO2S-2 heater circuit referring to “DTC P0037 /
P0038: HO2S Heater Control Circuit Low / High
(Sensor-2)”.
Is circuit in good condition? Go to Step 6. Repair HO2S-2 circuit. If
circuit is OK, substitute
a known-good ECM and
recheck.
6 HO2S-2 check
1) Check HO2S-2 referring to “HO2S-1 and HO2S-2
Heater On-Vehicle Inspection in Section 1C”.
Is it in good condition? Substitute a known-
good ECM and recheck.
Replace HO2S-2.
Step Action Yes No
DTC detecting condition
Trouble area
DTC P0171:
Total fuel trim is higher than 35% or short term fuel trim is higher
than 20% for more than 1 min. continuously.
(2 driving cycle detection logic)
DTC P0172:
Total fuel trim is lower than –35% or short term fuel trim is lower
than –20% for more than 1 min. continuously.
(2 driving cycle detection logic) • Vacuum leakage
• Exhaust gas leakage
• Fuel pressure out of specification
• Fuel injector malfunction
• Heated oxygen sensor-1 malfunction
• MAF sensor malfunction
• ECT sensor malfunction

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-101
NOTE
When DTC P0122 and P0222 are indicated together, it is possible that “RED” wire open circuit.

DTC Confirmation Procedure
1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Keep the accelerator pedal at idle position for 2 seconds.
4) Keep the accelerator pedal at fully depressed position for 2 seconds.
5) Repeat Step 3) and 4) for 3 times.
6) Check DTC.
DTC Troubleshooting
NOTE
• When measuring circuit voltage, resistance and/ or pulse signal at ECM connector, connect the
special tool to ECM and/or the ECM connectors re ferring to “Inspection of ECM and Its Circuits”.
• Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and confirm that the trouble has been corrected.

Step Action YesNo
1 Was “Engine and Emission Control System Check”
performed? Go to Step 2.
Go to “Engine and
Emission Control
System Check”.
2 TP sensor and its circuit check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Turn ON ignition switch, check “TP Sensor 2 Volt” displayed on scan tool when accelerator pedal is idle
position and fully depressed.
Is displayed TP sensor value as described voltage in “Scan
To o l D a t a ” ? Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
Go to Step 3.
3 ECM voltage check
1) Disconnect connector from electric throttle body with
ignition switch turned OFF.
2) Check for proper connection to electric throttle body at “RED”, “WHT” and “BLK” wire terminals.
3) If OK, measure voltage between “RED” wire terminal of electric throttle body connector and engine ground with
ignition switch turned ON.
Is voltage 4 – 6 V? Go to Step 6.
Go to Step 4.
"GRN"
"RED"
"WHT"
"BLK"
"LT GRN/BLK"
"LT GRN/RED"
I4RS0B110022-02

Downloaded from www.Manualslib.com manuals search engine 1A-102 Engine General Information and Diagnosis:
DTC P0223: Throttle / Pedal Position Sensor / Switch “B” (Sub) Circuit HighS7RS0B1104038
Wiring Diagram
Refer to “DTC P0222: Throttle / Pedal Position Sensor / Switch “B” (Sub) Circuit Low”.
DTC Detecting Condition and Trouble Area4
ECM voltage check
1) Turn OFF ignition switch.
2) Remove ECM from its br acket with ECM connectors
connected.
3) Check for proper connection of ECM connector at “C37- 43” terminal.
4) If OK, measure voltage between “C37-43” terminal of ECM connector and engine ground with ignition switch
turned ON.
Is voltage 4 – 6 V? “RED” wire is open or
high resistance circuit.
Go to Step 5.
5 Wire harness check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure resistance between “C37-43” terminal of ECM connector and engine ground.
Is resistance infinity? Substitute a known-
good ECM and recheck.
“RED” wire is shorted to
ground circuit.
6 Wire harness check
1) Measure voltage between “WHT” wire terminal of
electric throttle body connector and engine ground with
ignition switch turned ON.
Is voltage 4 – 6 V? Go to Step 9.
Go to Step 7.
7 Wire harness check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Check for proper connection of ECM connector at “C37- 40” and “C37-42” terminals.
3) If OK, measure resistance between “WHT” and “BLK” wire terminals of electric throttle body connector.
Is resistance infinity? Go to Step 8.
“WHT” wire is shorted to
“BLK” wire.
8 Wire harness check
1) Measure resistance between “WHT” wire terminal of
electric throttle body connector and engine ground with
ignition switch turned OFF.
Is resistance infinity? Substitute a known-
good ECM and recheck.
“WHT” wire is shorted to
ground circuit.
9 Electric throttle body check
1) Check TP sensor referring to “Throttle Position Sensor
Performance Check” under “Electric Throttle Body
Assembly On-Vehicle Inspection in Section 1C”.
Is output voltage within specified value? Substitute a known-
good ECM and recheck.
Replace electric throttle
body.
Step
Action YesNo
DTC detecting condition Trouble area
Output voltage of throttle position sensor (sub) is more than specified
value for specified time continuously.
(1 driving detection logic) • Throttle position sensor (sub) circuit
• Electric throttle body assembly
•ECM

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-103
NOTE
When DTC P0123 and P0223 are indicated together, it is possible that “RED” wire shorted to power
circuit and/or “BLK” wire open.

DTC Confirmation Procedure
1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Keep the accelerator pedal at idle position for 2 seconds.
4) Keep the accelerator pedal at fully depressed position for 2 seconds.
5) Repeat Step 3) and 4) for 3 times.
6) Check DTC.
DTC Troubleshooting
NOTE
• When measuring circuit voltage, resistance and/ or pulse signal at ECM connector, connect the
special tool to ECM and/or the ECM connectors re ferring to “Inspection of ECM and Its Circuits”.
• Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and confirm that the trouble has been corrected.

Step Action YesNo
1 Was “Engine and Emission Control System Check”
performed? Go to Step 2.
Go to “Engine and
Emission Control
System Check”.
2 TP sensor and its circuit check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Turn ON ignition switch, check “TP Sensor 2 Volt” displayed on scan tool when accelerator pedal is idle
position and fully depressed.
Is displayed TP sensor value as described voltage in “Scan
To o l D a t a ” ? Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
Go to Step 3.
3 ECM voltage check
1) Disconnect connector from electric throttle body with
ignition switch turned OFF.
2) Check for proper connection to electric throttle body at “RED”, “WHT” and “BLK” wire terminals.
3) If OK, measure voltage between “RED” wire terminal of electric throttle body connector and engine ground with
ignition switch turned ON.
Is voltage 4 – 6 V? Go to Step 6.
Go to Step 4.
"GRN"
"RED"
"WHT"
"BLK"
"LT GRN/BLK"
"LT GRN/RED"
I4RS0B110022-02

Downloaded from www.Manualslib.com manuals search engine 1A-104 Engine General Information and Diagnosis:
4Wire harness check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Check for proper connection of ECM connector at “C37- 43” terminal.
3) Measure voltage between “C37-43” terminal of ECM connector and engine ground with ignition switch turned
ON.
Is voltage 0 V? Substitute a known-
good ECM and recheck.
“RED” wire is shorted to
power circuit.
5 Wire harness check
1) Measure voltage between “WHT” wire terminal of
electric throttle body connector and engine ground with
ignition switch turned ON.
Is voltage 4 – 6 V? Go to Step 9.
Go to Step 6.
6 Wire harness check
1) Turn OFF ignition switch.
2) Remove ECM from its br acket with ECM connectors
connected.
3) Check for proper connection of ECM connector at “C37- 43” and “C37-40” terminals.
4) If OK, measure voltage between “C37-40” terminal of ECM connector and engine ground with ignition switch
turned ON.
Is voltage 4 – 6 V? “WHT” wire is open or
high resistance circuit.
Go to Step 7.
7 Wire harness check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure resistance between “WHT” and “RED” wire terminals of electric thrott le body assembly connector.
Is resistance infinity? Go to Step 8.
“WHT” wire is shorted to
“RED” wire.
8 Wire harness check
1) Turn ON ignition switch.
2) Measure voltage between “C37-40” terminal of ECM
connector and engine ground.
Is voltage 0 V? Substitute a known-
good ECM and recheck.
“WHT” wire is shorted to
power circuit.
9 Ground circuit check
1) Turn OFF ignition switch.
2) Measure resistance between “BLK” wire terminal of
electric throttle body connector and engine ground.
Is resistance below 5
Ω? Go to Step 11. Go to Step 10.
10 Ground circuit check
1) Remove ECM from its br acket with ECM connectors
connected.
2) Check for proper connection of ECM connector at “C37- 42” terminal.
3) Measure resistance between “C37-42” terminal of ECM connector and engine ground with ignition switch turned
OFF.
Is resistance below 5
Ω? “BLK” wire is open or
high resistance circuit.
Faulty ECM ground
circuit. If circuit is OK,
substitute a known-
good ECM and recheck.
Step Action Yes No

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-107
DTC P0327 / P0328: Knock Sensor 1 Circuit Low / HighS7RS0B1104040
Wiring Diagram
DTC Detecting Condition and Trouble Area
DTC Confirmation Procedure1) Connect scan tool to DLC with ignition switch turned OFF.
2) Turn ON ignition switch and clear DTC by using scan tool.
3) Start engine and run it for 10 sec.
4) Check DTC by using scan tool. 11
Engine mechanical system check
1) Check engine mechanical parts or system which can
cause engine rough idle or poor performance.
• Engine compression (Refer to “Compression Check in Section 1D”.)
• Valve lash (Refer to “Valve Lash (Clearance) Inspection in Section 1D”.)
• Valve timing (Refer to “Timing Chain and Chain Tensioner Removal and Installation in Section 1D”.)
Are they in good condition? Check wire harness and
connection of ECM
ground, ignition system
and fuel injector for
intermittent open and
short.
Repair or replace
defective part.
Step
Action YesNo
E23 C37
34
1819
567
1011
17
20
47 46
495051
2122
52 16
25 9
24
14
29
55
57 54 53
59
60 58 2
262728
15
30
56 4832 31
34353637
40
42 39 38
44
45 43 41 331
1213
238
34
1819
567
1011
17
20
47 46
495051
2122
52 16
25 9
24
14
29
55
57 54 53
59
60 58 2
262728
15
30
56 4832 31
34353637
40
42 39 38
44
45 43 41 331
1213
238
1 2
REDC37-56
5 V
I4RS0A110031-01
1. Knock sensor
2. ECM
DTC detecting condition Trouble area
DTC P0327:
Voltage of knock sensor is less than 1.23 V for 0.5 seconds
continuously.
(1 driving cycle detection logic)
DTC P0328:
Voltage of knock sensor is 3.91 V or more for 0.5 seconds
continuously
(1 driving cycle detection logic) • Knock sensor circuit (open or short)
• Knock sensor
•ECM

Downloaded from www.Manualslib.com manuals search engine 1A-108 Engine General Information and Diagnosis:
DTC Troubleshooting
NOTE
• When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the
special tool to ECM and/or the ECM connectors re ferring to “Inspection of ECM and Its Circuits”.
• Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and confirm that the trouble has been corrected.

Step Action YesNo
1 Was “Engine and Emission Control System Check”
performed? Go to Step 2.
Go to “Engine and
Emission Control
System Check”.
2 Knock sensor circuit check
1) Remove ECM from its br acket with ECM connectors
connected.
2) Measure voltage between “C37-56” terminal of ECM connector and vehicle body ground with engine running.
Is voltage within 1.23 – 3.91 V? Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”. If OK, substitute a
known-good ECM and
recheck.Go to Step 3.
3 Knock sensor circuit for open check
1) Disconnect connector from knock sensor with ignition
switch turned OFF.
2) Turn ON ignition switch, measure voltage between “RED” wire of knock sensor connector and engine
ground.
Is voltage 4 – 6 V? Go to Step 6.
Go to Step 4.
4 Knock sensor circuit for open check
1) Turn ON ignition switch, measure voltage between “C37-
56” terminal of ECM connector and engine ground
Is voltage 4 – 6 V? “RED” wire is open
circuit.
Go to Step 5.
5 Knock sensor circuit for short check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure resistance between “C37-56” terminal of ECM connector and vehicle body ground.
Is resistance infinity? Go to Step 6.
“RED” wire is shorted to
ground circuit.
If wire is OK, substitute
a known-good ECM and
recheck.
6 Knock sensor circuit for short check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Turn ON ignition switch, measure voltage between “C37- 56” terminal of ECM connector and vehicle body ground.
Is voltage 0 V? Go to Step 7.
“RED” wire is shorted to
other circuit.
I2RH01110089-01

Downloaded from www.Manualslib.com manuals search engine 1A-110 Engine General Information and Diagnosis:
DTC Troubleshooting
NOTE
• When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the
special tool to ECM and/or the ECM connectors re ferring to “Inspection of ECM and Its Circuits”.
• Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and confirm that the trouble has been corrected.

Step Action YesNo
1 Was “Engine and Emission Control System Check”
performed? Go to Step 2.
Go to “Engine and
Emission Control
System Check”.
2 CKP sensor and connector for proper installation check
Is CKP sensor installed properly and connector connected
securely? Go to Step 3.
Correct.
3 Wire harness and connection check
1) Disconnect connector from CKP sensor with ignition
switch turned OFF.
2) Check for proper connection to CKP sensor at “BLK/ RED”, “PNK” and “BLK/ORN” wire terminals.
3) If OK, turn ON ignition switch and check voltage at “BLK/ RED”, “PNK” and “BLK/ORN” wire terminals of
disconnected CKP sensor connector.
CKP sensor voltage
Terminal “B+”: 10 – 14 V
Terminal “Vout”: 4 – 5 V
Terminal “GND”: 0 V
Is check result satisfactory? Go to Step 7. Go to Step 4.
4 Was terminal “Vout” voltage in Step 3 within specification? Go to Step 5. “PNK” wire is open or
shorted to ground /
power supply circuit.
If wire and connection
are OK, substitute a
known-good ECM and
recheck.
5 Ground circuit check
1) Turn ignition switch to OFF position.
2) Measure resistance between “BLK/ORN” wire terminal
of CKP sensor connector and engine ground.
Is measured resistance value less than 3
Ω? Go to Step 6. “BLK/ORN” wire is open
or high resistance.
I2RH0B110048-01

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-113
3Wire harness and connection check
1) Disconnect connector from CMP sensor.
2) Check for proper connection to CMP sensor at “BLK/
RED”, “RED/YEL” and “B LK/ORN” wire terminals.
3) If OK, turn ON ignition switch and check voltage at “BLK/ RED”, “RED/YEL” and “BLK/ORN” wire terminals of
disconnected CMP sensor connector.
CMP sensor voltage
Terminal “B+”: 10 – 14 V
Terminal “Vout”: 4 – 5 V
Terminal “GND”: 0 V
Is check result satisfactory? Go to Step 7. Go to Step 4.
4 Was terminal “Vout” voltage in Step 3 within specification? Go to Step 5. “RED/YEL” wire is open
or shorted to ground /
power supply circuit.
If wire and connection
are OK, substitute a
known-good ECM and
recheck.
5 Ground circuit check
1) Turn ignition switch to OFF position.
2) Measure resistance between “BLK/ORN” wire terminal
of CMP sensor connector and engine ground.
Is measured resistance value less than 3
Ω? Go to Step 6. “BLK/ORN” wire is open
or high resistance
circuit.
6 Was terminal “B+” voltage in Step 3 within specification? Go to Step 7. “BLK/RED” wire is open
circuit. If wire and
connection are OK,
substitute a known-
good ECM and recheck.
7 CMP sensor check
1) Check CMP sensor and signal rotor tooth referring to
“Camshaft Position (CMP) Sensor Inspection in Section
1C”.
Is check result satisfactory? Substitute a known-
good ECM and recheck.
Replace CMP sensor
and/or intake camshaft.
Step Action Yes No
I4RS0B110094-01

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-115
DTC Troubleshooting
NOTE
• When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the
special tool to ECM and/or the ECM connectors re ferring to “Inspection of ECM and Its Circuits”.
• Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and confirm that the trouble has been corrected.

Step Action YesNo
1 Was “Engine and Emission Control System Check”
performed? Go to Step 2.
Go to “Engine and
Emission Control
System Check”.
2 Ignition spark check
1) Check that each spark plug sparks referring to “Ignition
Spark Test in Section 1H”.
Is check result satisfactory? Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.Go to Step 3.
3 Ignition coil power, output and ground circuit check
1) Disconnect ignition coil connector of the cylinder found
as faulty in Step 2.
2) Check ignition coil circuit of the cylinder found as faulty in Step 2 for the following.
• Voltage between power circuit wire terminal of ignition coil connector and vehicle body ground is 10 – 14 V
with ignition switch turned ON.
• Voltage between output circuit wire terminal of ignition coil connector and vehicle body ground is 4 – 6 V with
ignition switch turned ON.
• Resistance between ground circuit wire terminal of ignition coil connector and vehicle body ground is less
than 2 Ω.
Are they in good condition? Go to Step 4.
Repair or replace
defective wire.
4 Ignition coil check
1) Replace ignition coil for No.1 and No.4 spark plugs with
ignition coil for No.2 and No.3 spark plugs.
Is the cylinder found as faulty in good condition now? Faulty ignition coil. Go to Step 5.
5 Ignition coil output circuit check
1) Disconnect connectors from ECM.
2) Check ignition coil circuit of the cylinder found as faulty
in Step 2 for the following.
• Resistance of output wire circuit between ignition coil
connector and ECM connector is less than 2 Ω.
• Resistance of output wire circuit between ignition coil connector and vehicle b ody ground is infinity.
Are they in good condition? Substitute a known-
good ECM and recheck.
Repair or replace
defective wire.