2001 SUZUKI GRAND VITARA exhaust system

6-1-28 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
TP SENSOR VOLT (TP Sensor Output Voltage, V)
Throttle Position Sensor reading provides throttle valve opening information in the from of voltage.
O2S B1 S1 (HO2S Bank 1 Sensor 1 Output Voltage, V) / O2S B2 S1 (HO2S Bank 2 Sensor 1 Output
Voltage, V)
It indicates output voltage of HO2S SENSOR 1 installed on exhaust manifold (pre-catalyst).
O2S B1 S2 (HO2S Bank 1 Sensor 2 Output Voltage, V) / O2S B2 S2 (HO2S Bank 2 Sensor 2 Output
Voltage, V)
If indicates output voltage of HO2S SENSOR 2 installed on exhaust pipe (post-catalyst). It is used to detect cat-
alyst deterioration.
FUEL SYSTEM B1 (Fuel System Bank 1 Status) / Fuel System B2 (Fuel System Bank 2 Status)
Air/fuel ratio feedback loop status displayed as one of the followings.
OPEN : Open loop-has not yet satisfied conditions to go closed loop.
CLOSED : Closed loop-using oxygen sensor(s) as feedback for fuel control.
OPEN-DRIVE COND : Open loop due to driving conditions (Power enrichment, etc.).
OPEN SYS FAULT : Open loop due to detected system fault.
CLOSED-ONE O2S : Closed loop, but fault with at least one oxygen sensor may be using single oxygen sensor
for fuel control.
CALC LOAD (Calculated Load Value, %)
Engine load displayed as a percentage of maximum possible load. Value is calculated mathematically using the
formula : actual (current) intake air volume ÷ maximum possible intake air volume x 100%.
TOTAL FUEL TRIM (%)
The value of total fuel trim is obtained by putting values of short term fuel trim and long term fuel trim together.
This value indicates how much correction is necessary to keep the air/fuel mixture stoichiometrical.
CANIST PRG DUTY (EVAP Canister Purge Flow Duty, %)
This parameter indicates valve ON (valve open) time rate within a certain set cycle of EVAP canister purge valve
which controls the amount of EVAP purge.
VEHICLE SPEED (km/h, MPH)
It is computed based on pulse signals from vehicle speed sensor on transfer or transmission.
FUEL CUT (ON/OFF)
ON : Fuel being cut (output signal to injector is stopped).
OFF : Fuel not being cut.
MAP (Manifold Absolute Pressure, mmHg, kPa)
This parameter indicates the pressure in the intake manifold absolute pressure.
A/C CONDENSER FAN (ON/OFF)
This parameter indicates the state of the A/C Condenser Fan control signal.
BLOWER FAN (ON/OFF)
This parameter indicates the state of the blower fan motor switch.

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.

6-1-80 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0300/P0301/P0302/P0303/P0304/P0305/P0306 Random Misfire/Cylinder
1 Misfire/Cylinder 2 Misfire/Cylinder 3 Misfire/Cylinder 4 Misfire Detected/Cyl-
inder 5 Misfire Detected/Cylinder 6 Misfire Detected
SYSTEM DESCRIPTION
ECM (PCM) measures the angle speed of the crankshaft based on the pulse signal from the CKP sensor and
CMP sensor for each cylinder. If it detects a large change in the angle speed of the crankshaft, it concludes
occurrence of a misfire. When the number of misfire is counted by the ECM (PCM) beyond the DTC detecting
condition, it determines the cylinder where the misfire occurred and outputs it as DTC.
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 speed recorded as freeze frame data (V) ± 5 km/h when detecting misfire.
4) Keep driving above vehicle speed for 5 min.
5) Stop vehicle and check DTC (or pending DTC) by using scan tool.DTC DETECTING CONDITION TROUBLE AREA
DTC P0300 :
• Misfire which causes catalyst to overheat during 200 engine
revolutions is detected at 2 or more cylinders. (MIL flashes as
long as this misfire occurs continuously.)
• Misfire which affects exhaust emission adversely during 1000
engine revolutions is detected at 2 or more cylinders (2 driving
cycle detection logic)• Ignition system
• Fuel injector and its circuit
• Fuel line pressure
• Engine compression
• Abnormal air drawn in
• EGR system
• Fuel level sensor
• Valve lash adjuster
• Valve timing DTC P0301, P0302, P0303, P0304, P0305, P0306 :
• Misfire which causes catalyst to overheat during 200 engine
revolutions is detected at 1 cylinder. (MIL flashes as long as
this misfire occurs continuously.)
• Misfire which affects exhaust emission adversely during 1000
engine revolutions is detected at 1 cylinder
(2 driving cycle detection logic)
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 – 70°C (18 – 158°F)
Engine coolant temp. : – 8°C (18°F) or higher
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-89
DTC P0400 Exhaust Gas Recirculation Flow Malfunction
SYSTEM/WIRING DIAGRAM
1. EGR valve 5. ECM (PC)
2. Intake manifold 6. MAP sensor
3. Exhaust gas 7. Main fuse
4. Sensed information 8. Main relay

6-1-94 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0420 Catalyst System Efficiency Below Threshold (Bank 1)
SYSTEM DIAGRAM
CIRCUIT DESCRIPTION
Exhaust oxygen concentration at the pre-catalyst and the post-catalyst of WU-TWC is detected from HO2S-1
and HO2S-2 respectively and accordingly ECM (PCM) controls the closed loop which then controls the fuel
injection volume. (Refer to Section 6E2.) While the above control is going on and if WU-TWC is in good condi-
tion, the output voltage of HO2S-2 is maintained at specified level. As WU-TWC becomes deteriorated, even
when the above control is going on, the exhaust gas which has passed WU-TWC then passes HO2S-2 at the
exhaust oxygen concentration similar to that of the pre-catalyst without being oxygenated or converted. Thus,
waveforms of HO2S-1 and HO2S-2 output voltages become alike. ECM (PCM) judges deterioration of WU-TWC
by comparing waveforms of HO2S-1 and HO2S-2.
DTC DETECTING CONDITION AND TROUBLE AREA
1. HO2S-1 (Bank-1) 4. TWC
2. HO2S-2 (Bank-1) 5. ECM (PCM)
3. WU-TWC
DTC DETECTING CONDITION TROUBLE AREA
While running under conditions described for DTC CON-
FIRMATION PROCEDURE, output waveform of HO2S-1
becomes similar to that of HO2S-2.
(2 driving cycle detection logic)• Exhaust gas leakage
• Warm up three way catalytic converter
• Heated oxygen sensor – 2 or its circuit
•ECM (PCM)