1999 SUZUKI GRAND VITARA sensor

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.

6-1-74 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0161 HO2S-2 (Bank 2) Heater Circuit Malfunction
WIRING DIAGRAM
Refer to DTC P0156.
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)

6-1-76 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0171/P0172 Fuel System Too Lean/Rich (Bank 1)
DTC DETECTING CONDITION AND POSSIBLE CAUSE
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 warm up
engine completely.
3) Increase vehicle speed to 50 – 60 km/h (30 – 40 mph).
4) Keep driving above vehicle speed for 3 min. or more.
5) Stop vehicle and check pending DTC by using scan tool.DTC DETECTING CONDITION TROUBLE AREA
When running after engine warmed (2 driving cycle
detection logic).
• Short term fuel trim exceeding 15 % or long term fuel
trim exceeding 20 % and total trim exceeding 43 % is
detected.
– Fuel system too lean
• Short term fuel trim less than – 11 % or long term fuel
trim less than – 11 % and total trim less than – 30 % is
detected.
– Fuel trim too rich• Vacuum leaks (air inhaling)
• Exhaust gas leakage
• Fuel pressure out of specification
• Heated oxygen sensor malfunction
• EGR system malfunction
• MAF sensor poor performance
• ECT sensor poor performance
• Fuel level sensor.
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. at start : – 8 – 60°C (18 – 140°F)
Engine coolant temp. at start : – 8 – 95°C (18 – 203°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : 110°C (230°F) or lower

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-77
TROUBLESHOOTING
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 Is there DTC (s) other than “DTC P0171/
P0172”?Go to applicable DTC
FLOW TABLE.Go to Step 3.
3 Check intake system and exhaust system for
leakage.
Are intake system and exhaust system in good
condition?Go to Step 4. Repair or replace.
4 Check fuel pressure referring to “TABLE B-3” in
this section.
Is check result satisfactory?Go to Step 5. Repair or replace.
5 Check fuel injectors referring to “FUEL INJEC-
TOR INSPECTION” in Section 6E2.
Is check result satisfactory?Go to Step 6. Faulty injector (s).
6 Check fuel level sensor referring to “FUEL
LEVEL SENSOR” in Section 6E2.
Is check result satisfactory?Go to Step 7. Faulty fuel level sensor or
its circuit.
7 Check MAF sensor for performance referring to
“MASS AIR FLOW SENSOR” in Section 6E2.
Is check result satisfactory?Go to Step 8. Faulty MAF sensor or its
circuit.
8 Check ECT sensor referring to Section 6E2.
Is check result satisfactory?Go to Step 9. Faulty ECT sensor.
9 Check HO2S-1 referring to “DTC P0130 DIAG.
FLOW TABLE”.
Is check result satisfactory?Substitute a known-good
ECM (PCM) and recheck.Faulty HO2S-1.

6-1-78 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0174/P0175 Fuel System Too Lean/Rich (Bank 2)
DTC DETECTING CONDITION AND POSSIBLE CAUSE
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 warm up
engine completely.
3) Increase vehicle speed to 50 – 60 km/h (30 – 40 mph).
4) Keep driving above vehicle speed for 3 min. or more.
5) Stop vehicle and check pending DTC by using scan tool.DTC DETECTING CONDITION TROUBLE AREA
When running after engine warmed (2 driving cycle
detection logic).
• Short term fuel trim exceeding 15 % or long term fuel
trim exceeding 20 % and total trim exceeding 43 % is
detected.
– Fuel system too lean
• Short term fuel trim less than – 11 % or long term fuel
trim less than – 11 % and total trim less than – 30 % is
detected.
– Fuel trim too rich• Vacuum leaks (air inhaling)
• Exhaust gas leakage
• Fuel pressure out of specification
• Heated oxygen sensor malfunction
• EGR system malfunction
• MAF sensor poor performance
• ECT sensor poor performance
• Fuel level sensor.
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. at start : – 8 – 60°C (18 – 140°F)
Engine coolant temp. at start : – 8 – 95°C (18 – 203°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : 110°C (230°F) or lower

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-79
TROUBLESHOOTING
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 Is there DTC (s) other than “DTC P0174/
P0175”?Go to applicable DTC
FLOW TABLE.Go to Step 3.
3 Check intake system and exhaust system for
leakage.
Are intake system and exhaust system in good
condition?Go to Step 4. Repair or replace.
4 Check fuel pressure referring to “TABLE B-3” in
this section.
Is check result satisfactory?Go to Step 5. Repair or replace.
5 Check fuel injectors referring to “FUEL INJEC-
TOR INSPECTION” in Section 6E2.
Is check result satisfactory?Go to Step 6. Faulty injector (s).
6 Check fuel level sensor referring to “FUEL
LEVEL SENSOR” in Section 6E2.
Is check result satisfactory?Go to Step 7. Faulty fuel level sensor or
its circuit.
7 Check MAF sensor for performance referring to
“MASS AIR FLOW SENSOR” in Section 6E2.
Is check result satisfactory?Go to Step 8. Faulty MAF sensor or its
circuit.
8 Check ECT sensor referring to Section 6E2.
Is check result satisfactory?Go to Step 9. Faulty ECT sensor.
9 Check HO2S-1 referring to “DTC P0150 DIAG.
FLOW TABLE”.
Is check result satisfactory?Substitute a known-good
ECM (PCM) and recheck.Faulty HO2S-1.