1999 SUZUKI GRAND VITARA sensor

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-105
DTC P0500 (DTC No.24) Vehicle Speed Sensor Malfunction
WIRING DIAGRAM
DTC DETECTING CONDITION AND TROUBLE AREA
1. Speedometer
2. Vehicle speed sensor
3. Cruise control module (if equipped)
4. ECM (PCM)
DTC DETECTING CONDITION TROUBLE AREA
Vehicle speed signal not inputted although fuel is kept
cut for longer than 5 seconds
(2 driving cycle detection logic)•Vehicle speed sensor circuit open or short
•Vehicle speed sensor
•Vehicle speed sensor drive gear or driven gear
•Speedometer malfunction
•Cruise control module malfunction (if equipped)
•ECM (PCM)

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)

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-111
DTC P1408 Manifold Absolute Pressure Sensor Circuit Malfunction
WIRING DIAGRAM
DTC DETECTING CONDITION AND TROUBLE AREA
DTC CONFIRMATION PROCEDURE
1. MAP sensor
2. ECM (PCM)
DTC DETECTING CONDITION TROUBLE AREA
•While engine is running after being warmed up and
with throttle opening smaller than specification,
higher than 4.6 V manifold absolute pressure sen-
sor output voltage is detected for specified time or
with throttle opening larger than specification, lower
than 0.2 V manifold absolute pressure output volt-
age is detected for specified time.
(2 driving cycle detection logic)•Manifold absolute pressure sensor
•Manifold absolute pressure sensor vacuum pas-
sage
•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 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)

6-1-112 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.

6-1-122 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
3 Check IAC valve referring to “IAC VALVE
INSPECTION” in Section 6E2.
Is check result as specified?Go to Step 4. IAC valve malfunction, “BLU/
BLK”, “LT GRN/BLK”, “PPL/
BLK”, “GRY/BLU” or “PPL/
YEL” wire open or short or
poor coupler connection.
If all above are OK, substi-
tute a known-good ECM
(PCM) and recheck.
4 Was idle speed within specification in
Step 1?Check for following :
FIA valve, Vacuum leaks, air inhal-
ing, EVAP canister purge control
system, accessory engine load,
stuck of PCV valve, clog of idle air
passage, MAF sensor, TP sensor,
ECT sensor, EGR valve malfunc-
tion (leakage from valve seat), A/C
signal, transmission range switch
signal and power steering switch
signal.Go to Step 5.
5 Was idle speed higher than specification
in Step 1?Go to Step 6. Go to Step 8.
6 Check A/C (input) signal circuit referring
to Step 1 of “Table B-5”. (A/C signal can
be also checked by using SUZUKI scan
tool.)
Is it in good condition?Go to Step 7. A/C signal circuit open or
short, or A/C system mal-
function.
7 Was IAC duty less than about 2% in Step
1 of this table?
Check FIA valve.
Check abnormal air inhaling from
intake manifold, throttle body, PCV
valve and EVAP canister purge
control system.Check TP sensor (closed
throttle position) and ECT
sensor for performance.
If sensors are OK, substitute
a known-good ECM (PCM)
and recheck.
8 Check transmission range switch signal
referring to “INSPECTION OF ECM
(PCM) AND ITS CIRCUIT” in this section.
Is check result satisfactory?Go to Step 9. Transmission range switch
malfunction or its circuits
open or short.
9 Was IAC duty more than about 30% in
Step 1 of this table?Check parts or system which can
cause engine low idle.
Check FIA valve.
Air inhaling from between throttle
body and MAF sensor, EGR valve
malfunction (leakage from valve
seat), accessory engine load, clog
of idle air passage and etc.Substitute a known-good
ECM (PCM) and recheck. Step Action Yes No

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-123
Table B-5 A/C Signal Circuits Inspection (If Equipped)
WIRING DIAGRAM
INSPECTION
1. A/C control module (amplifier)
2. ECM (PCM)
Step Action Yes No
1 Check A/C Signal Circuit.
1) Check voltage at terminal E61-17 with ignition
switch ON.
A/C signal circuit specification :
A/C switch and/or heater blower switch OFF (A/
C is not operating) : 10 – 14 V
Both A/C switch and heater blower switch ON :
0 – 1.5 V
Are check result as specified?Go to Step 2.“YEL/BLK” circuit open or
short, Evaporative tem-
perature is below 1°C
(34°F) or faulty A/C sys-
tem.
2 Check A/C Cut Signal Circuit.
1) Check voltage at terminal E61-8.
A/C cut signal specification :
While engine running and A/C switch and/or
heater blower switch OFF
(A/C is not operating) : 0 – 1.5 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 result as specified?A/C control signal cir-
cuits are in good con-
dition.“GRY/WHT” circuit open
or short, Poor perfor-
mance of ECT sensor, TP
sensor, Engine start sig-
nal inputted or A/C ampli-
fier malfunction.
If none of the above
exists, substitute a
known-good ECM (PCM)
and recheck.