1999 SUZUKI GRAND VITARA troubleshooting

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.

6-1-106 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 warm up
engine completely.
3) Increase vehicle speed to 100 – 110 km/h (60 – 70 mph).
4) Release accelerator pedal and with engine brake applied, keep vehicle coasting for 5 seconds or more and
then stop vehicle.
5) Check pending 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 persons, a driver and a tester, on a level road.
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)
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 speedometer indicate vehicle speed? Faulty “BLU/YEL” wire or
poor C51-1-14 connection.
If wire and connection are
OK, intermittent trouble or
faulty ECM (PCM).
Check for intermittent refer-
ring to “INTERMITTENT
AND POOR CONNECTION”
in Section 0A.Go to Step 3.
3 VSS power supply voltage check:
1) With ignition switch OFF, remove VSS
coupler.
2) With ignition switch ON leaving engine
OFF, check voltage between C20-3 and
C20-2 terminal of VSS coupler.
Is voltage 10 – 14 V?Go to Step 4.“BLK/BLU” or “BLK/YEL”
wire open/short.
4 VSS signal harness check:
1) With ignition switch ON leaving engine
OFF, check voltage between C20-1 and
C20-2 terminal of VSS coupler.
Is voltage 4 V or more?Go to Step 5. Go to Step 6.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-109
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) Run engine at idle speed for 1 min.
4) Check pending DTC by using scan tool.
TROUBLESHOOTING
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)
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 Idle speed check:
1) Check engine idle speed referring to “IDLE
SPEED/IDLE AIR CONTROL DUTY
INSPECTION” in Section 6E2.
Is engine idle speed within specification?Intermittent trouble or
faulty ECM (PCM).
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.Go to Step 3.
3 IAC valve check:
1) Check IAC valve referring to “IAC VALVE
INSPECTION” in Section 6E2.
Is check result as specified?Go to Step 6. Go to Step 4.
4 IAC valve circuit check:
1) With ignition switch OFF, disconnect ECM
(PCM) couplers.
2) Check for proper connection to IAC valve at
C51-1-4, C51-1-5, C51-1-16 and C51-1-17
terminals.
3) If OK, check resistance between C51-1-4
and C51-1-5, C51-1-16 and C51-1-17.
Is each resistance 51 – 67 Ω?Go to Step 5.“LT GRN/BLK”, “PPL/
BLK”, “GRY/BLU” or
“PPL/YEL” wire open or
short.
If wire and connections
are OK, replace IAC
valve.
5 IAC valve power supply voltage check:
1) Connect ECM (PCM) couplers.
2) With ignition switch OFF, disconnect C29
coupler of IAC valve.
3) With ignition switch ON, check voltage
between C29-2 and ground, C29-5 and
ground.
Is each voltage 10 – 14 V?IAC valve or ECM (PCM)
malfunction.Open “BLU/BLK” wire.

6-1-110 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0601 (DTC No.71) Internal Control Module Memory Check Sum Error
SYSTEM DESCRIPTION
Internal control module is installed in ECM (PCM).
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.
3) Start engine and run it at idle if possible.
4) Check DTC by using scan tool.
TROUBLESHOOTING
Substitute a known-good ECM (PCM) and recheck.6 Was idle speed higher than specification in
Step 2?Check FIA valve for mal-
function.
Check abnormal air inhal-
ing from intake manifold,
throttle body, PCV valve
and EVAP canister purge
control system.Check parts or system
which can cause engine
low idle.
Check FIA valve for stuck.
Air inhaling from between
throttle body and MAF
sensor, EGR valve mal-
function (leakage from
valve seat), accessory
engine load, clog of idle
air passage, engine
mechanical, engine over-
heat and etc. Step Action Yes No
DTC DETECTING CONDITION TROUBLE AREA
Data write error or check sum error ECM (PCM)

6-1-112 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
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) Run engine at idle speed for 1 min. (engine coolant temp. becomes 76°C (169°F) or more).
4) Increase vehicle speed to 80 km/h (50 mph).
5) Keep driving above vehicle speed for 1 min (Change of vehicle speed is permitted in this step).
6) Stop vehicle and check pending DTC by using scan tool.
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 MAP sensor signal check :
1) Remove ECM (PCM) cover.
2) Check voltage between C51-3-8 and C51-
3-25 under following conditions.
•With ignition switch ON leaving engine OFF
: 0.2 V or higher
•At idling : 4.6 V or lower
Is check result as specified?Intermittent trouble or
faulty ECM (PCM).
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.Go to Step 3.
3 MAP sensor check :
1) Disconnect connector from MAP sensor.
2) Check for proper connection to MAP sensor
at each terminal.
3) If OK, check MAP sensor for performance
referring to “MAP SENSOR INSPECTION”
in Section 6E2.
Is check result satisfactory?“RED/WHT”, “GRY/YEL”
or “GRY/RED” circuit
open/short.
If wire and connections
are OK, substitute a
known-good ECM (PCM)
and recheck.Replace MAP sensor.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-113
DTC P1450/P1451 Barometric Pressure Sensor Circuit Malfunction/Perfor-
mance Problem
SYSTEM DESCRIPTION
Barometric pressure sensor is installed in ECM (PCM).
DTC DETECTING CONDITION AND TROUBLE AREA
DTC CONFIRMATION PROCEDURE
For DTC P1450
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC by using scan tool and run engine for 1 min.
3) Check DTC by using scan tool.
For DTC P1451
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 to normal operating temperature.
3) Increase engine speed to 3,000 r/min. in 3rd gear in case of M/T and “2” range in case of A/T.
4) Release accelerator pedal and with engine brake applied, keep vehicle coasting for 5 sec. or more (keep fuel
cut condition for 5 sec. or more). If fuel cut condition is not kept for 5 sec. or more, coast down a slope in
engine speed 1600 – 3000 r/min for 5 sec. or more.
5) Stop vehicle and run engine at idle.
6) Repeat steps 3) – 5) 2 times.
7) Check pending DTC by using scan tool.
TROUBLESHOOTING (DTC P1450/P1451)
DTC DETECTING CONDITION TROUBLE AREA
DTC P1450 :
Barometric pressure out of specification is detected.•Barometric pressure sensor in ECM
(PCM)
DTC P1451 :
While running under conditions described for “DTC CONFIRMATION
PROCEDURE”, barometric pressure value compared with intake
manifold vacuum value in fuel cut state is not as specified.
(2 driving cycle detection logic)•Manifold absolute pressure sensor
performance problem
•Barometric pressure sensor in 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.
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE DIAG. FLOW
TABLE” in this section.
2 Is DTC P1451 set? Go to Step 3. Substitute a known-good
ECM (PCM) and recheck.
3 MAP sensor check :
1) Check MAP sensor and its circuit referring to
Steps 2 and 3 of “DTC P1408 Diag. Flow Table”.
Is check result satisfactory?Substitute a
known-good
ECM (PCM) and
recheck.MAP sensor or its circuit mal-
function.

6-1-114 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P1500 Engine Starter Signal 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 by using scan tool, then start engine and run it for 3 min. or more.
3) Check pending DTC by using scan tool.
TROUBLESHOOTING
1. Engine start switch in ignition (main) switch 2. Starting motor 3. Transmission range sensor (switch) 4. ECM (PCM)
DTC DETECTING CONDITION TROUBLE AREA
•Engine starts even though vehicle is at stop and engine start signal is
not inputted.
or
•Engine start signal is inputted continuously for specified time while
engine is running.
(2 driving cycle detection logic)•Engine start signal 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)
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 Check for voltage at terminal C51-1-24 of
ECM (PCM) connector connected, under fol-
lowing condition.
Engine starter signal specification :
While engine cranking : 6 – 14 V
After starting engine : 0 – 1 V
Is voltage as specified?Poor C51-1-24 connection or
intermittent trouble.
Check for intermittent referring to
“INTERMITTENT AND POOR
CONNECTION” in Section 0A.
If wire and connections are OK,
substitute a known-good ECM
(PCM) and recheck.“BLK/YEL” circuit open.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-115
DTC P1510 Ecm Back-Up Power Supply Malfunction
WIRING DIAGRAM
CIRCUIT DESCRIPTION
Battery voltage is supplied to keep DTC memory, values that ECM has learned to control engine, etc. in ECM
even when ignition switch is turned OFF.
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 1min.
3) Check DTC by using scan tool.
TROUBLESHOOTING
1. Main fuse box 3. ECM (PCM)
2. To DLC
DTC DETECTING CONDITION TROUBLE AREA
Back-up circuit voltage lower than specification is detected
while engine is running.•ECM (PCM) back-up 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)
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE DIAG. FLOW
TABLE” in this section.
2 Battery voltage supply circuit check :
1) Remove ECM (PCM) cover.
2) While engine running, check voltage between E61-
2 and ground.
Is voltage 10 – 14 V?Poor E61-2 connection or
intermittent trouble.
Check for intermittent referring
to “INTERMITTENT AND
POOR CONNECTION” in
Section 0A.
If wire and connections are
OK, substitute a known-good
ECM (PCM) and recheck.“WHT” circuit open or short.