1999 SUZUKI GRAND VITARA o2 sensor

6-1-88 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
Fig. for Step 45 CMP sensor (REF) signal check :
1) With ignition switch OFF, connect CMP sensor
coupler.
2) Disconnect couplers from ignition coil assembly
and fuel injectors.
3) With ignition switch ON and crankshaft turned
slowly, check voltage between C51-1-13 and
C51-3-26 terminal.
Does voltmeter indicator deflect between 0 – 1 V
and 3 – 5.25 V 4 times while crankshaft turned two
revolutions?Go to Step 6. Faulty “YEL/GRN” wire
or CMP sensor.
If OK, substitute a
known-good ECM
(PCM) and recheck.
6 CMP sensor (POS) signal check :
1) With ignition switch ON and crankshaft turned
slowly, check voltage between C51-1-12 and
C51-3-26 terminal.
Does voltmeter indicator deflect between 0 – 1 V
and 3 – 5.25 V 6 times while crankshaft turned two
revolutions?Poor C51-1-12 and/or
C51-3-13 terminal of
ECM (PCM) coupler con-
nection.
If OK, substitute a
known-good ECM (PCM)
and recheck.Faulty “YEL/BLU” wire
or CMP sensor.
If OK, substitute a
known-good ECM
(PCM) and recheck. Step Action Yes No
1. Disconnected CMP sensor coupler
2. “BLU/BLK” wire (C09-2) terminal
3. “GRY/YEL” wire (C09-1) terminal

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

6-1-90 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
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 warm up
engine completely.
3) Increase vehicle speed to 55 – 60 km/h (35 – 40 mph).
4) Keep driving above vehicle speed for 7 min. or more.
5) Increase vehicle speed to 100 – 110 km/h (60 – 70 mph).
6) Release accelerator pedal and with engine brake applied, keep vehicle coasting and then stop vehicle.
7) Check if pending DTC exists by using scan tool. If not, check if EGR system monitoring test has completed
by using scan tool. If not in both of above checks (i.e., no pending DTC and EGR system monitoring test not
completed), check vehicle conditions (environmental) and repeat Steps 3) through 6).DTC DETECTING CONDITION TROUBLE AREA
During deceleration (engine speed high with closed
throttle position) in which fuel cut is involved, difference
in intake manifold pressure between when EGR valve is
opened and when it is closed is smaller than specified
value.
(2 driving cycle detection logic)•EGR valve
• EGR passage
• Manifold absolute pressure 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)
1. Vehicle speed km/h (mph)
2. Step

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-91
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 P0403 (EGR circuit malfunction)? Go to DTC P0403 Diag.
Flow Table.Go to Step 3.
3 Do you have SUZUKI scan tool? Go to Step 4. Go to Step 6.
4 EGR valve operation check :
1) With ignition switch OFF, install SUZUKI
scan tool.
2) Check EGR system referring to Section
6E2.
Is it in good condition?Go to Step 5. Go to Step 6.
5 MAP sensor check :
1) Check MAP sensor for performance refer-
ring to Section 6E2.
Is check result satisfactory?Intermittent trouble or
faulty ECM (PCM). Check
for intermittent referring to
“INTERMITTENT AND
POOR CONNECTION” in
Section 0A.Repair or replace.
6 EGR valve power supply circuit check :
1) With ignition switch OFF, disconnect EGR
valve coupler.
2) With ignition switch ON, check voltage
between C04-2 and ground, C04-5 and
ground.
Is each voltage 10 – 14 V?Go to Step 7. Faulty “BLU/BLK” wire.
7 EGR valve stepper motor coil circuit check :
1) With ignition switch OFF, connect EGR
valve coupler and disconnect ECM (PCM)
couplers.
2) Check resistance between C51-3-4 and
C51-2-12, C51-2-13, C51-2-14, C51-2-15.
Is each resistance 20 – 24 Ω at 20°C (68°F)?Go to Step 8. Faulty EGR valve.
8 MAP sensor check :
1) Check MAP sensor for performance refer-
ring to Section 6E2.
Is check result satisfactory?EGR passage clogged or
EGR valve malfunction.
If all above are OK, inter-
mittent trouble or faulty
ECM (PCM).
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.Repair or replace.

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)

6-1-96 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0430 Catalyst System Efficiency Below Threshold (Bank 2)
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 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-2) 4. TWC
2. HO2S-2 (Bank-2) 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)

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-103
DTC P0460 Fuel Level Sensor Circuit High Input
WIRING DIAGRAM/CIRCUIT DESCRIPTION
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 run
engine for 1 min.
3) Check pending DTC by using scan tool.
1. Fuel level sensor
2. Fuel meter in combination meter
3. ECM (PCM)
DTC DETECTING CONDITION TROUBLE AREA
Fuel level sensor output voltage higher than specified
value is detected for specified time.
(2 driving cycle detection logic)•Fuel level gauge or its circuit
•Fuel level sensor or its circuit
•ECM (PCM)
NOTE:
Check to make sure that following condition is satisfied when using this “DTC CONFIRMATION PRO-
CEDURE”.
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)

6-1-104 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
TROUBLESHOOTING
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE” in this
section.
2 Does fuel level meter in combination meter indi-
cate “E” (Empty)?Replenish fuel tank with
fuel and go to Step 3.Go to Step 3.
3 Check fuel level sensor and its circuit:
1) Check voltage between terminal E61-28 and
ground with ignition switch ON.
Is it about 7.1 V or more?Go to Step 4. Intermittent trouble or
faulty ECM (PCM).
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section
0A.
4 Is voltage in Step 3 “9 – 14 V”?“BLU/WHT” wire shorted
to power circuit or fuel
level meter malfunction.Go to Step 5.
5 Check Fuel Level Sensor:
1) Turn ignition switch OFF and disconnect fuel
level sensor connector (L15 – R01).
2) Check for proper connection to fuel level
sensor at L15-4 and L15-3 terminals.
3) If OK, then check resistance between R01-4
and R01-3 terminals. (Refer to “FUEL LEVEL
GAUGE (SENDER GAUGE)” in Section 8C.)
Is value close to one of above values indicated?“BLU/WHT” or “BLK/YEL”
circuit open.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.Check “BLU/WHT” and
“BLK/YEL” wires
between R01 and R02
connections.
If OK, replace fuel level
sensor.