2001 SUZUKI GRAND VITARA engine start circuit

6-1-44 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
Table A-2 Malfunction Indicator Lamp Circuit Check – Lamp Remains “ON”
after Engine Starts
WIRING DIAGRAM/CIRCUIT DESCRIPTION
Refer to TABLE A-1.
INSPECTION
2 ECM power and ground circuit check :
Does engine start?Go to Step 3. Go to “TABLE A-3 ECM
(PCM) POWER AND
GROUND CIRCUIT
CHECK” in this section.
If engine is not cranked,
go to “DIAGNOSIS” in
Section 6G.
3 MIL circuit check :
1) Turn ignition switch OFF and disconnect
connectors from ECM.
2) Check for proper connection to ECM at ter-
minal E61-7.
3) If OK, then using service wire, ground termi-
nal E61-7 in connector disconnected.
Does MIL turn on at ignition switch ON?Substitute a known-good
ECM (PCM) and recheck.Bulb burned out or “PPL/
YEL” wire circuit open. Step Action Yes No
Step Action Yes No
1 DTC check :
1) With ignition switch OFF, install scan tool.
2) Start engine and check DTC.
Is there any malfunction DTC (s).Go to Step 2 of “ENGINE
DIAG. FLOW TABLE” in
this section.Go to Step 2.
2 MIL circuit check :
1) With ignition switch OFF, disconnect cou-
plers from ECM (PCM).
Does MIL turn ON at ignition switch ON?“PPL/YEL” wire shorted to
ground circuit.Substitute a known-good
ECM (PCM) and recheck.

6-1-46 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
Table A-5 ECM (PCM) Power and Ground Circuit Check – MIL Doesn’t Light at
Ignition Switch ON and Engine Doesn’t Start Though It Is Cranked Up
WIRING DIAGRAM
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, the main relay turns ON (the contact point closes) and the main power is
supplied to ECM (PCM).
1. MIL
2. To ignition switch
3. Main fuse
4. Main relay
5. ECM (PCM)

6-1-56 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0121 Throttle Position Circuit Range/Performance Problem
WIRING DIAGRAM/CIRCUIT DESCRIPTION
Refer to DTC P0120.
DTC DETECTING CONDITION AND TROUBLE AREA
DTC CONFIRMATION PROCEDURE
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and start
engine.
3) Increase vehicle speed to 60 km/h (40 mph).
4) Keep driving above vehicle speed for 5 min (Change of vehicle speed is permitted in this step).
5) Stop vehicle and run engine at idle speed for 1 min.
6) Increase vehicle speed till engine speed is reached 2,000 – 3,000 r/min in proper gear.
7) Keep driving at that engine speed for 30 sec or more (Engine speed is kept constant in this step).
8) Stop vehicle.
9) Repeat step 6) to 8).
10) Check pending DTC by using scan tool.DTC DETECTING CONDITION TROUBLE AREA
Throttle opening change is smaller than specification
while intake air volume changes and engine is running at
constant speed. (2 driving cycle detection logic)•TP sensor
•ECM (PCM)
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.
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude barometric pressure : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-59
DTC CONFIRMATION PROCEDURE
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and start
engine.
3) Increase vehicle speed to 55 km/h (35 mph) or more.
4) Keep driving above vehicle speed for 2 min. or more (Change of vehicle speed is permitted in this step).
5) Stop vehicle, and run engine at idle speed for 1 min.
6) Check if pending DTC exists by using scan tool. If not, check if oxygen sensor monitoring test has completed
by using scan tool. If not in both of above checks (i.e., no pending DTC and oxygen sensor monitoring test
not completed), check vehicle condition (environmental) and repeat step 3) through 6).
TROUBLESHOOTING
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.
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE
DIAG. FLOW
TABLE” in this sec-
tion.
2 HO2S-1 output voltage check :
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 to enrich A/F mixture
and take foot off from pedal to enlean and check HO2S
output voltage displayed on scan tool. See Fig.
Is over 0.6 V and below 0.3 V indicated?Go to Step 4. Go to Step 3.
3 HO2S-1 check :
1) With ignition switch OFF, disconnect HO2S-1 connec-
tor.
2) Check for proper connection to HO2S-1 at each termi-
nal.
3) If OK, connect voltmeter “1” and “2” terminal of HO2S-1
connector.
4) Start engine and check voltmeter while repeating rac-
ing engine.
Is over 0.6 V and below 0.3 V indicated?“RED” or “GRY/
YEL” circuit open or
short.
If wire and connec-
tions are OK, sub-
stitute a known-
good ECM (PCM)
and recheck.Replace HO2S-1.

6-1-64 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
1) Connect scan tool with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data in ECM memory by using scan
tool and start engine.
3) Increase vehicle speed to 55 km/h (40 mph) or more.
4) Keep driving above vehicle speed till engine is warmed up completely (Changed of vehicle speed is permit-
ted in this step).
5) Keep driving 50 – 60 km/h (30 – 40 mph) for 8 min. or more.
6) Stop vehicle and check if pending DTC exists by using scan tool. If not, check if oxygen sensor heater moni-
toring test has completed by using scan tool. If not in both of above checks (i.e., no pending DTC and oxy-
gen sensor heater monitoring test not completed), check vehicle conditions (environmental) and repeat
Steps 3) through 6).
TROUBLESHOOTING
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE” in this
section.
2 HO2S-2 output voltage check :
1) Connect scan tool to DLC with ignition
switch OFF.
2) Drive vehicle about 35 mph, 55 km/h for 2
min. or more.
3) Stop vehicle and check HO2S-2 output volt-
age displayed on scan tool while repeating
racing engine.
Is over and below 0.3 V indicated?Go to Step 4. Go to Step 3.
3 HO2S-2 check :
1) With ignition switch OFF, disconnect HO2S-
2 coupler.
2) Connect voltmeter between “2” and “1” of
HO2S-2 coupler.
3) Start engine and check voltmeter while
repeating racing engine.
Is over and below 0.3 V indicated?“RED/BLK” or “GRY/YEL”
circuit open/short.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.Replace HO2S-2.
4 Short term fuel trim check :
1) Run engine at 2000 r/min. for 60 sec.
2) With engine idling, check short term fuel
trim displayed on scan tool.
Is it within – 20 to +20 %?Intermittent trouble or
faulty ECM (PCM).
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.Go to DTC P0171/P0172
Diag. Flow Table.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-65
DTC P0141 HO2S-2 (Bank 1) Heater Circuit Malfunction
WIRING DIAGRAM
Refer to DTC P0136.
DTC DETECTING CONDITION AND TROUBLE AREA
DTC CONFIRMATION PROCEDURE
1) Connect scan tool with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data in ECM memory by using scan
tool and start engine.
3) Increase vehicle speed to 50 – 60 km/h (30 – 40 mph).
4) Keep driving above vehicle speed for 5 min. (Change of vehicle speed is permitted in this step).
5) Stop vehicle and check if pending DTC exists by using scan tool. If not, check if oxygen sensor heater moni-
toring test has completed by using scan tool. If not in both of above checks (i.e., no pending DTC and oxy-
gen sensor heater monitoring test not completed), check vehicle conditions (environmental) and repeat
Steps 3) through 5).DTC DETECTING CONDITION TROUBLE AREA
Following condition is detected when HO2S-2 heater operates (2
driving cycle detection logic).
• Current of HO2S-2 heater is more than 11.4 A or less than 0.32 A,
or
• Voltage of HO2S-2 heater is more than 13.8 V or less than 8.7 V.HO2S-2 heater or its circuit
ECM (PCM)
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.
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)

6-1-68 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC CONFIRMATION PROCEDURE
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and start
engine.
3) Increase vehicle speed to 55 km/h (35 mph) or more.
4) Keep driving above vehicle speed for 2 min. or more (Change of vehicle speed is permitted in this step).
5) Stop vehicle, and run engine at idle speed for 1 min.
6) Check if pending DTC exists by using scan tool. If not, check if oxygen sensor monitoring test has completed
by using scan tool. If not in both of above checks (i.e., no pending DTC and oxygen sensor monitoring test
not completed), check vehicle condition (environmental) and repeat step 3) through 6).
TROUBLESHOOTING
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.
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE
DIAG. FLOW
TABLE” in this sec-
tion.
2 HO2S-1 output voltage check :
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 to enrich A/F mixture
and take foot off from pedal to enlean and check HO2S
output voltage displayed on scan tool. See Fig.
Is over 0.6 V and below 0.3 V indicated?Go to Step 4. Go to Step 3.
3 HO2S-1 check :
1) With ignition switch OFF, disconnect HO2S-1 connec-
tor.
2) Check for proper connection to HO2S-1 at each termi-
nal.
3) If OK, connect voltmeter “1” and “2” terminal of HO2S-1
connector.
4) Start engine and check voltmeter while repeating rac-
ing engine.
Is over 0.6 V and below 0.3 V indicated?“RED/BLU” or
“GRY/YEL” circuit
open or short.
If wire and connec-
tions are OK, sub-
stitute a known-
good ECM (PCM)
and recheck.Replace HO2S-1.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-73
1) Connect scan tool with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data in ECM memory by using scan
tool and start engine.
3) Increase vehicle speed to 55 km/h (40 mph) or more.
4) Keep driving above vehicle speed till engine is warmed up completely (Changed of vehicle speed is permit-
ted in this step).
5) Keep driving 50 – 60 km/h (30 – 40 mph) for 8 min. or more.
6) Stop vehicle and check if pending DTC exists by using scan tool. If not, check if oxygen sensor heater moni-
toring test has completed by using scan tool. If not in both of above checks (i.e., no pending DTC and oxy-
gen sensor heater monitoring test not completed), check vehicle conditions (environmental) and repeat
Steps 3) through 6).
TROUBLESHOOTING
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE” in this
section.
2 HO2S-2 output voltage check :
1) Connect scan tool to DLC with ignition
switch OFF.
2) Drive vehicle about 35 mph, 55 km/h for 2
min. or more.
3) Stop vehicle and check HO2S-2 output volt-
age displayed on scan tool while repeating
racing engine.
Is over and below 0.3 V indicated?Go to Step 4. Go to Step 3.
3 HO2S-2 check :
1) With ignition switch OFF, disconnect HO2S-
2 coupler.
2) Connect voltmeter between “2” and “1” of
HO2S-2 coupler.
3) Start engine and check voltmeter while
repeating racing engine.
Is over and below 0.3 V indicated?“RED/YEL” or “GRY/YEL”
circuit open/short.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.Replace HO2S-2.
4 Short term fuel trim check :
1) Run engine at 2000 r/min. for 60 sec.
2) With engine idling, check short term fuel
trim displayed on scan tool.
Is it within – 20 to +20 %?Intermittent trouble or
faulty ECM (PCM).
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.Go to DTC P0174/P0175
Diag. Flow Table.