Page 130 of 557

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-79
Main
fuseMain relay
To other valves
EVAP canister
purge valve
EVAP canister
purge valveSurge
tank
Tank pressure
control valveFuel vapor separator
Fuel filter cap
Fuel
level
sensor
Fuel tank EVAP
canister
DTC P0443 PURGE CONTROL VALVE CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
Canister Purge control valve circuit is opened
or shorted.“R/G” circuit open or short
“W/BI” circuit open
Canister purge valve malfunction
DTC CONFIRMATION PROCEDURE
1) Clear DTC with ignition switch ON.
2) Select “DTC” mode on scan tool and check DTC.
INSPECTION
STEPACTIONYESNO
1Check EVAP canister purge valve operation
1) With ignition switch OFF, disconnect coupler
from canister purge valve.
2) Check resistance of EVAP canister purge
valve. See Fig. 1.
Resistance between
two terminals : 30 – 34 Ω at 20C (68F)
Resistance between
terminal and body : 1M Ω or higher
Is it as specified?“R/G” circuit open or
short.Replace EVAP canister
purge valve.
Page 133 of 557

6-82 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
Vehicle speed
sensor in
combination meterC03-2
C03-2
DTC P0500 VEHICLE SPEED SENSOR (VSS) MALFUNCTION (M / T)
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
VSS signal not inputted while vehicle running in “D”
range or during fuel cut at deceleration.
2 driving cycle detection logic, continuous monitoring“B/Bl” circuit open
“Y/G” circuit open or short
VSS malfunction
ECM malfunction
Speedometer cable malfunction
DTC CONFIRMATION PROCEDURE
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
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.
1) Clear DTC and warm up engine to normal operating temperature.
2) Increase vehicle speed to 50 mph, 80 km / h in 3rd gear or “2” range while observing vehicle speed displayed
on scan tool.
3) Release accelerator pedal and with engine brake applied, keep vehicle coasting (fuel cut condition) for 4 sec.
or more.
4) Check pending DTC and DTC.
Page 135 of 557

6-84 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
Vehicle speed sensor (on A / T)
Counter
shaft
gearPCMC03-2
C03-13
Bl
P
C03-2
C03-13
DTC P0500 VEHICLE SPEED SENSOR (VSS) MALFUNCTION FOR A / T
VEHICLE (A / T)
CIRCUIT DESCRIPTION – Refer to Section 6E1 for VSS operation.
DTC DETECTING CONDITIONPOSSIBLE CAUSE
While fuel is kept cut at lower than 4000 r / min for
longer than 4 sec.
VSS signal not inputted.
2 driving cycle detection logic, continuous
monitoring.“BI” or “P” circuit open or short.
Vehicle speed sensor malfunction.
Foreign material being attached or sensor installed
improperly.
Gear damaged.
DTC CONFIRMATION PROCEDURE
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
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.
1) Turn ignition switch OFF and then ON.
2) Clear DTC and warm up engine to normal operating temperature.
3) Increase vehicle speed to 50 mph, 80 km / h in “2” range.
4) Release accelerator pedal and with engine brake applied, keep vehicle coasting (fuel cut condition) for 4 sec.
or more.
5) Stop vehicle and check DTC and pending DTC.
Page 137 of 557

Main
fuseMain relay
Idle speed
control relay
To TP sensor
Idle speed control actuator
6-86 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
DTC P0505 IDLE CONTROL SYSTEM MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
DTC will set when A, B or C condition is met.
A: Throttle opening change is small as compared with
electrically live time.
B: Throttle valve opening is not within its target range
with CTP switch ON.
C: Drive voltage exists though ECM (PCM) is not
outputting ISC drive command.Malajusted accelerater cable
Poor movement of throttle valve
Closed throttle position switch malfunction
Idle speed control actuator malfunction
Idle speed control relay malfunction
“Gr / B”, “Gr / Y”, “Gr”, “Gr / R”, “Gr / G”, “Lg” or “B/Bl”
circuit open or short
Throttle position sensor malfunction
ECM (PCM) malfunction
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Start cold engine.
4) Run it idle for 5 min.
5) Select “DTC” mode on scan tool and check DTC.
NOTE:
If engine speed changes up and down when engine speed is increased by opening throttle valve more
than half but not changing its opening, it is possible that closed throttle position switch is malfunction-
ing.
Page 138 of 557

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-87
Fig. 1 for Step 3 Fig. 2 for Step 3 Fig. 3 for Step 3
1. ISCA relay
2. Relay box
DTC P0505
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check Idle Control System.
1) Connect SUZUKI scan tool to DLC with ignition
switch OFF, set parking brake and block drive
wheels.
2) Warm up engine to normal operating
temperature.
3) Clear DTC and select “MISC TEST” mode on
SUZUKI scan tool.
Is it possible to control (increase and reduce)
engine idle speed by using SUZUKI scan tool?Check TP sensor (Go to
DTC P0121 Flow Table)
If TP sensor is OK,
intermittent trouble or
faulty ECM (PCM).
Check for intermittent
referring to “Intermittent
and Poor Connection”
in Section 0A.Go to Step 3.
3Check ISC Relay.
1) Ignition switch OFF and remove ISC relay
(“ISCA”).
2) Check for proper connection to ISC relay at
terminals 3 and 4.
3) Check resistance between each two terminals.
Between terminals 1 and 2: Infinity
Between terminals 3 and 4: 100 – 120 Ω
4) Check that there is continuity between
terminals 1 and 2 when battery is connected to
terminals 3 and 4.
Is ISC relay in good condition?Go to Step 4.Replace ISC relay.
4Check Idle Speed Control Actuator.
1) Check ISC actuator operation by referring to
ISC ACTUATOR INSPECTION in Section 6.
Is it good condition?Check “Gr / B”, “Gr / Y”,
“Gr” and “Gr / R” circuit
for open and short.
If wires and connections
are OK, substitute a
known-good ECM
(PCM) and recheck.Replace throttle lower
body with ISC actuator.
Page 143 of 557

6-92 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
Fig. 1 for Step 1
DTC P1450 BAROMETRIC PRESSURE SENSOR LOW / HIGH INPUT
DTC P1451 BAROMETRIC PRESSURE SENSOR PERFORMANCE PROBLEM
WIRING DIAGRAM / CIRCUIT DESCRIPTION
Barometric pressure sensor is installed in ECM (PCM).
DTC DETECTING CONDITION
POSSIBLE CAUSE
DTC P1450:
Barometric pressure: 136 kPa 1025 mmHg or higher, or
33 kPa 250 mmHg or lowerECM (PCM) (barometric pressure sensor)
malfunction
DTC P1451:
Vehicle stopped.
Engine cranking.
Difference between barometric pressure and intake
manifold absolute pressure is 26 kPa, 200 mmHg or more.
2 driving cycle detection logic, monitoring once / 1 driving.Manifold absolute pressure sensor and its
circuit malfunction
ECM (PCM) (barometric pressure sensor)
malfunction
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Turn ignition switch ON for 2 sec., crank engine for 2 sec. and run it at idle for 1 min.
4) Check pending DTC in “ON BOARD TEST” or “PENDING DTC” mode and DTC in “DTC” mode.
INSPECTION
DTC P1450:
Substitute a known-good ECM (PCM) and recheck.
DTC P1451:
NOTE:
Note that atmospheric pressure varies depending on weather conditions as well as altitude.
Take that into consideration when performing these check.
STEP
ACTIONYESNO
11) Connect scan tool to DLC with ignition switch
OFF.
2) Turn ignition switch ON and select “DATA
LIST” mode on scan tool.
3) Check manifold absolute pressure. See Fig. 1.
Is it barometric pressure (approx. 100 kPa,
760 mmHg) at sea level?Substitute a known-
good ECM (PCM) and
recheck.Check intake manifold
pressure sensor and its
circuit.
Go to P0105 DIAG.
FLOW TABLE.
Page 144 of 557

Main
fuse
M / T vehicle
Ignition
switch
(starter
switch)Starter
A / T vehicle
Main
fuse
Ignition
switch
(starter
switch)Transmission
range sensor (switch)
StarterPCM
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-93
DTC P1500 ENGINE STARTER SIGNAL CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
High voltage at terminal C01-16 for 3 min. after engine
start.
Low voltage at terminal C01-16 during starting engine.
2 driving cycle detection logic, continuous monitoring.“B/Y” circuit open
ECM (PCM) malfunction
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON, crank engine and run it at idle for 3 min.
3) Check pending DTC in “ON BOARD TEST” or “PENDING DTC” mode and DTC in “DTC” mode.
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check for voltage at terminal C01-16 of ECM
(PCM) connector connected, under following
condition.
While engine cranking : 6 – 10 V
After starting engine : 0 V
Is voltage as specified?Poor C01-16
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.“B/Y” circuit open.
Page 153 of 557

A/C
amplifier(A / C ON output signal)
(A / C input signal)
6-102 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
TABLE B-4 A / C SIGNAL CIRCUITS CHECK (VEHICLE WITH A / C)
INSPECTION
STEPACTIONYESNO
1Check A / C (Input) Signal Circuit.
1) Check voltage at terminal C03-19.
While engine running and A / C switch
and / or heater blower switch OFF
(A / C is not operating) : 10 – 14 V
While engine running and both A / C
switch and heater blower switch ON
(A / C is operating) : About 0 V
Are check results as specified?Go to Step 2.“Bl / R” wire open or
short.
Poor C03-19
connection.
Poor A / C amplifier
coupler connection
or faulty A / C
system.
2Check A / C ON (Output) Signal Circuit.
1) Check voltage at terminal C03-17.
While engine running and A / C switch
and / or heater blower switch OFF
(A / C is not operating) : About 0 V
While engine running at idle speed
and both A / C switch and heater blower
switch ON (A / C is operating) : 10 – 14 V
Are check results as specified?A / C control signal
circuits are in good
condition.“Lg / R” wire open or
short.
Poor performance of
ECT sensor, TP
sensor.
Engine start signal
inputted or
Poor C03-17
connection.
If none of the above
exists, substitute a
known-good ECM
(PCM) and recheck.