check engine SUZUKI GRAND VITARA 1999 2.G Service Manual

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-49
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 at idle speed for 20 sec. or more.
3) Check DTC by using scan tool.
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 person, 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” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE” in this
section.
2 MAF sensor check :
1) Connect scan tool to DLC with ignition
switch OFF.
2) Start engine and check MAF value dis-
played on scan tool. (Refer to “SCAN TOOL
DATA” in this section for normal value.)
Is normal value indicated?Intermittent trouble.
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.Go to Step 3.
3 MAF sensor power supply check :
1) With ignition switch OFF, disconnect MAF
sensor coupler.
2) With ignition switch ON, check voltage
between E154-3 of MAF sensor coupler and
ground.
Is voltage 10 – 14 V?Go to Step 4. Faulty “BLU/BLK” wire.
4 MAF sensor output voltage check :
1) With ignition switch OFF, connect MAF sen-
sor coupler.
2) Remove ECM (PCM) cover.
3) With ignition switch ON leaving engine OFF,
check voltage between C51-3-10 and C51-
3-5 terminal.
Is voltage 1.0 – 1.6 V?Poor C51-3-10 or/C51-3-5
terminal connection.
If OK, substitute a known-
good ECM (PCM) and
recheck.Faulty “PPL/WHT” wire.
Poor E154 coupler termi-
nal connection.
If wire and connection are
OK, substitute a known-
good MAF sensor and
recheck.

6-1-50 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0110 (DTC No.23, 25) Intake Air Temp. (IAT) Circuit Malfunction
WIRING DIAGRAM
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 at idle speed and engine coolant temp. 110°C (230°F) or lower for 10 sec. or more.
3) Check DTC by using scan tool.
1. IAT sensor
2. ECM (PCM)
DTC DETECTING CONDITION TROUBLE AREA
Any one of the conditions are detected for 5 sec. con-
tinuously.
• Low intake air temperature (high voltage-high resis-
tance)
• High intake air temperature (Low voltage-low resis-
tance)• IAT sensor circuit
• IAT sensor
• ECM (PCM) malfunction

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-51
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 Check IAT sensor and its circuit :
1) Connect scan tool with ignition switch OFF.
2) Turn ignition switch ON.
3) Check intake air temp. displayed on scan
tool.
Is – 40°C (– 40°F) or 165°C (329°F) indicated?Go to Step 3. Intermittent trouble.
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.
3 Check wire harness :
1) Disconnect IAT sensor connector with igni-
tion switch OFF.
2) Check for proper connection to IAT sensor
at “LT BLU” and “GRY/YEL” wire terminals.
If OK, then with ignition switch ON, is voltage
applied to “LT BLU” wire terminal about 4 – 6 V?Go to Step 4. “LT BLU” wire open or
short, or poor C51-3-1
connection.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.
4 Check wire harness :
1) Using service wire, connect IAT sensor con-
nector terminals.
2) Turn ignition switch ON and check intake air
temp. displayed on scan tool.
Is 165°C (329°F) indicated?Replace IAT sensor. “GRY/YEL” wire open or
poor C51-3-25 connec-
tion.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.

6-1-52 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0115 (DTC No.14, 15) Engine Coolant Temp. Circuit Malfunction
WIRING DIAGRAM
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 at idle speed for 10 sec. or more.
3) Check DTC by using scan tool.
1. ECT sensor
2. To combination (ECT) meter
3. ECM (PCM)
DTC DETECTING CONDITION TROUBLE AREA
Any one of the conditions are detected for 5 sec. continu-
ously.
• Low engine coolant temperature (high voltage-high
resistance)
• High engine coolant temperature (low voltage-low
resistance)ECT sensor circuit
ECT sensor
ECM (PCM)
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) 6-1-53
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 Check ECT sensor and its circuit :
1) Connect scan tool with ignition switch OFF.
2) Turn ignition switch ON.
3) Check engine coolant temp. displayed on
scan tool.
Is – 40°C (– 40°F) or 164°C (327°F) indicated?Go to Step 3. Intermittent trouble.
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.
3 Check wire harness :
1) Disconnect ECT sensor connector with igni-
tion switch OFF.
2) Check for proper connection to ECT sensor
at “ORN/BLK” and “GRY/YEL” wire termi-
nals.
If OK, then with ignition switch ON, is voltage
applied to “ORN/BLK” wire terminal about 4 – 6
V?Go to Step 4. “ORN/BLK” wire open or
short, or poor C51-3-2
connection.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.
4 Check wire harness :
1) Using service wire, connect ECT sensor
connector terminals.
2) Turn ignition switch ON and check engine
coolant temp. displayed on scan tool.
Is 164°C (327°F) indicated?Replace ECT sensor. “GRY/YEL” wire open or
poor C51-3-23 connec-
tion.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.

6-1-54 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0120 (DTC No.21, 22) Throttle Position Circuit Malfunction
WIRING DIAGRAM
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 at idle speed for 10 sec. or more.
3) Check DTC by using scan tool.
1. Throttle position sensor
2. ECM (PCM)
DTC DETECTING CONDITION TROUBLE AREA
Following conditions are detected for 5 sec. continuously.
• Engine running
• Signal voltage low or signal voltage high• TP sensor circuit
•TP sensor
•ECM (PCM)
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) 6-1-55
TROUBLESHOOTING
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Check TP sensor and its circuit.
1) Connect scan tool to DLC with ignition
switch OFF and then turn ignition switch
ON.
2) Check throttle valve opening percentage
displayed on scan tool.
Is it displayed 3% or less?
3) Check throttle valve opening percentage
displayed on scan tool while opening throttle
valve from idle position to full open position.
Is it displayed 96% or higher?Go to Step 3. Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection” in
Section 0A.
3 Check wire harness.
1) Disconnect connector from TP sensor with
ignition switch OFF.
2) Check for proper connection to TP sensor at
“GRY/RED”, “RED/GRN” and “GRY/YEL”
wire terminal.
3) If OK, then with ignition switch ON, check
voltage between each of “GRY/RED” or
“RED/GRN” wire terminals and body
ground.
Is voltage about 4 – 6 V at each terminal?Go to Step 4. “GRY/RED” wire open,
“GRY/RED” wire shorted
to ground circuit or power
circuit or “RED/GRN”
wire, “GRY/YEL” wire
open or shorted to ground
circuit or poor C51-3-13 or
C51-3-9 connection.
If wire and connection are
OK, substitute a known-
good ECM and recheck.
4 Check TP sensor.
1) Check resistance between terminals of TP
sensor referring to “TP SENSOR” in Section
6E2.
Are measured values within specifications?“RED/GRN” wire shorted
to power circuit.
If wire is OK, substitute a
known-good ECM (PCM)
and recheck.Replace TP sensor.

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) 6-1-57
TROUBLESHOOTING
Fig. for Steps 4 and 5Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE
DIAG. FLOW TABLE”
in this section.
2 Is there a DTC related to TP sensor (DTC P0120)? Go to applicable DTC
Diag. Flow Table.Go to Step 3.
3 Do you have SUZUKI scan tool ? Go to Step 4. Go to Step 5.
4 Check TP sensor and its circuit (using SUZUKI
scan tool) :
1) Turn ignition switch OFF and connect SUZUKI
scan tool to DLC.
2) Turn ignition switch ON and check TP sensor
output voltage when throttle valve is at idle posi-
tion and fully opened.
Does voltage vary within specified value linearly as
shown in the figure?Substitute a known-good
ECM (PCM) and recheck.Go to Step 6.
5 Check TP sensor and its circuit (not using SUZUKI
scan tool) :
1) Turn ignition switch ON.
2) Check voltage at terminal C51-3-9 of ECM con-
nector connected, when throttle valve is at idle
position and fully opened.
Does voltage vary within specified value linearly as
shown in the figure?If voltmeter was used,
check terminal C51-3-9 for
poor connection.
If OK, substitute a known-
good ECM (PCM) and
recheck.Go to Step 6.
6 Check TP sensor :
1) Turn ignition switch OFF.
2) Disconnect TP sensor connector.
3) Check for proper connection to TP sensor at
each terminal.
4) If OK, check TP sensor for resistance referring
to “TP SENSOR” in Section 6E2.
Is check result satisfactory?High resistance in “GRY/
RED”, “RED/GRN” or
“GRY/YEL” circuit.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.Replace TP sensor.
1. Voltage
2. Throttle opening
3. At idle position
4. Fully open

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.