2000 SUZUKI SWIFT sensor

6-108 ENGINE GENERAL INFORMATION AND DIAGNOSIS
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.
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 and recheck.
DTC P1451 :
DTC DETECTING CONDITION POSSIBLE CAUSE
DTC P1450 :
Barometric pressure : Sensor voltage is 4.7 V or higher, or
1.6 V or lowerECM (barometric pressure sensor) malfunc-
tion
DTC P1451 :
Vehicle stopped
Engine cranking
Difference between barometric pressure and intake mani-
fold absolute pressure is 26 kPa, 200 mmHg or more
Difference between intake manifold absolute pressure at
engine start and the pressure after engine start is 1.3 kPa,
10 mmHg or less.
✱2 driving cycle detection logic, monitoring once/1 driving.Manifold absolute pressure sensor and its
circuit malfunction
ECM (barometric pressure sensor) malfunc-
tion
NOTE:
Note that atmospheric pressure varies depending on weather conditions as well as altitude.
Take that into consideration when performing these check.
Step Action Yes No
1 Check Barometric Pressure Valve.
1) 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 and recheck.Go to Step 2.

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-109
Table 1
Fig. 1 for Step 1
Fig. 2 for Step 22 Check MAP Sensor.
1) Remove MAP sensor from intake manifold
and connect vacuum pump gauge to MAP
sensor. See Fig. 2.
2) Connect scan tool to DLC and turn ignition
switch ON.
3) Check intake manifold absolute pressure
displayed on scan tool for specified valve.
See Table 1.
Is check result satisfactory?Check air intake system
for air being drawn in and
engine compression.
If OK, then substitute a
known-good ECM and
recheck.Replace MAP sensor. Step Action Yes No
Applying Vacuum Displayed Value on Scan Tool
0 Barometric pressure
(Approx. 100 kPa, 760 mmHg)
27 kPa
200 mmHgBarometric pressure – 27 kPa
(Approx. 73 kPa, 560 mmHg)
67 kPa
500 mmHgBarometric pressure – 67 kPa
(Approx. 33 kPa, 260 mmHg)

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-115
INSPECTION
Fig. 1 for Step 3Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Is SUZUKI scan tool available? Go to Step 3. Go to Step 4.
3 Check PNP Signal (“D” range signal).
1) Connect SUZUKI scan tool to DLC with igni-
tion switch OFF. See Fig. 1.
2) Turn ignition switch ON and check PNP sig-
nal (“P/N” or “D” range) on display when
shifting selector lever to each range.
Is “D” range on display (Is 0 – 1 V indicated) no
matter which of “R”, “D”, “2” and “L” range posi-
tions selector lever may be at? See Table 1.Intermittent trouble or
faulty ECM. Check for
intermittent referring to
“Intermittent and poor
connection” in Section 0A.Go to Step 5.
4 Check PNP Signal (“D” range signal).
1) Turn ignition switch ON.
2) Check voltage at terminal C41-14 (Case of
TYPE A. See NOTE) or G02-6 (Case of
TYPE B. See NOTE) of ECM connector
connected. See Fig. 2.
Is “D” range on display (Is 0 – 1 V indicated) no
matter which of “R”, “D”, “2” and “L” range posi-
tions selector lever may be at? See Table 1.Intermittent trouble or
faulty ECM. Check for
intermittent referring to
“Intermittent and poor
connection” in Section 0A.Go to Step 5.
5Is “P/N range on display (Is 10 – 14 V indicated)
when selector lever is at one of “R”, “D”, “2” and
“L” range positions only?Check transmission range
switch and circuits refer-
ring to section 7B.Go to Step 6.
6 Check PNP Signal Circuit.
1) Turn ignition switch OFF.
2) Disconnect TCM connectors.
3) Check for proper connection to TCM at ter-
minal C44-8.
4) If OK, then check voltage at terminal
C44-8 in TCM connector disconnected, with
ignition switch ON.
Is it 10 – 14 V? See Fig. 3“GRN/ORN” circuit open,
poor transmission range
switch connector connec-
tion, select cable malad-
justed, transmission
range sensor malad-
justed or transmission
range sensor malfunction.
If all above are OK, sub-
stitute a known-good
TCM and recheck.“LT BLU” (Case of TYPE
A. See NOTE) or “GRN
RED” (Case of TYPE B.
See NOTE) circuit open or
poor C41-14 (Case of
TYPE A. See NOTE) or
G02-6 (Case of TYPE B.
See NOTE) connection.
If wire and connection are
OK, substitute a known-
good ECM and recheck.

6-122 ENGINE GENERAL INFORMATION AND DIAGNOSIS
TABLE B-4 IDLE AIR CONTROL SYSTEM CHECK
INSPECTION
1. IAC valve 2. Main relay 3. To TCM
[A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
GRN/RED
BLK/YEL
BRN/WHT
BLK/RED
BLK/RED
ECM
C41-10
C41-6
C41-5
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
3
1
2
C42-6 C41-14 [A]
G02-6 [B]
LT BLU [A]
GRN RED [B]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
Step Action Yes No
1 Check engine idle speed and IAC duty referring
to “Idle Speed/IAC Duty Inspection” in Section
6E1.
Is idle speed within specification?Go to Step 2. Go to Step 4.
2 Is IAC duty within specification in Step 1? Go to Step 3. Check for followings :
Vacuum leak
EVAP canister purge con-
trol system
Clog of IAC air passage
Accessory engine load
Closed throttle position
(TP sensor)
Stuck of PCV valve
3 Is engine idle speed kept specified speed even
with headlight ON?System is in good condi-
tion.Check IAC system for
operation referring to Step
2 of DTC P0505 Diag.
Flow Table.
4 Was idle speed higher than specification in
Step 1?Go to Step 5. Go to Step 8.

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-123
Fig. 1 for Step 105 Check A/C (input) signal circuit referring to Step
1 of Table B-5 A/C Signal Circuit Check, if
equipped. (A/C signal can be also checked by
using SUZUKI scan tool.)
Is it in good condition?Go to Step 6. Repair or replace A/C sig-
nal circuit or A/C system.
6 Check IAC system referring to Step 2 of DTC
P0505 Diag. Flow Table.
Is check result satisfactory?Go to Step 7. Go to Step 3 of DTC
P0505 Diag. Flow Table.
7 Was IAC duty less than about 3% (or more than
about 97% for OFF duty meter) in Step 1 of this
table?Check abnormal air inhal-
ing from air intake system,
PCV valve and EVAP
canister purge control
system.Check TP sensor (closed
throttle position) and ECT
sensor for performance.
If sensors are OK, substi-
tute a known-good ECM.
8 Is SUZUKI scan Tool available? Go to Step 9. Go to Step 10.
9 Check PNP signal (“D” range signal).
1) Connect SUZUKI scan tool to DLC with igni-
tion switch OFF.
2) Turn ignition switch ON and check PNP sig-
nal (“P/N” and “D” range) on display when
shifting selector lever to each range. See
Table 1.
Is check result satisfactory?Go to Step 11. Repair or replace.
10 Check PNP signal (“D” range signal).
1) Turn ignition switch ON.
2) Check voltage at terminal C41-14 (Case of
TYPE A. See NOTE) or G02-6 (Case of
TYOE B. See NOTE) of ECM connector
connected. See Fig. 1 and Table 1.
Is check result satisfactory?Go to Step 11. Repair or replace.
11 Check IAC system referring to Step 2 of DTC
P0505 Diag. Flow Table.
Is check result satisfactory?Go to Step 10. Go to Step 3 of DTC
P0505 Diag. Flow Table.
12 Was IAC duty more than about 30% (or less
than 70% for OFF duty meter) in Step 1 of this
table?Check parts or system
which can cause engine
low idle.
Accessory engine load
Clog of air passage
Etc.Substitute a known-good
ECM and recheck. Step Action Yes No
[A] : Case of TYPE A is shown (See NOTE)
[B] : Case of TYPE B is shown (See NOTE)

6-124 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Table 1 for Step 9 and 10
TABLE B-5 A/C SIGNAL CIRCUITS CHECK (VEHICLE WITH A/C)
Scan tool or voltmeter
SUZUKI SCAN TOOL
DISPLAYVOLTAGE AT C41-14
Selector lever
position“P” and “N” range P/N range 10 – 14V
“R”, “D”, “2” and “L” range D range 0 – 1V
1. Blower fan motor 3. A/C switch 5. A/C evaporator temp. sensor
2. Blower fan switch 4. A/C pressure switch 6. A/C compressor clutch
[A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
IG2
M
ECM
PNK/BLU
YEL/GRN
PNK/GRN
WHT/BLK
ORN
PNK/BLK
G02-13
C41-16
C41-1
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
1
234
5
6
C41-18 [A]
C42-30 [B]
G02-14 [A]
G02-1 [B]
G02-14 [B] G02-10 [A]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-125
INSPECTION
Fig. 1 for Step 1Step Action Yes No
1 Check evaporator temp. sensor resistance.
1) Disconnect ECM connectors with ignition
switch at OFF position.
2) Check resistance between G02-14 terminal
and G02-10 terminal (Case of TYPE A. See
NOTE) or between G02-1 terminal and
G02-14 terminal (Case of TYPE B. See
NOTE). See Fig. 1.
Is it within specification?
At 0°C 6.3 – 6.9 k
Ω
At 25°C 1.8 – 2.2 k
ΩGo to Step 2. Faulty A/C evaporator
temp. sensor or its circuit.
2 Check A/C switch signal.
1) Check voltage at C41-16 terminal under
each condition given below.
Ignition switch ON A/C switch OFF
: 10 – 14V
Ignition switch ON A/C switch ON
: 0 – 1V
Is check result satisfactory?Go to Step 3.“YEL/GRN” wire open or
short
Poor C41-16 terminal
connection
If wire and connection are
OK, substitute a known-
good ECM and recheck.
Go to Step 3.
3 1) Check voltage at C41-1 terminal under each
condition given below.
While engine running, A/C switch OFF
: 0 V
While engine running, A/C switch ON
: 10 – 14V
Is check result satisfactory?A/C control system cir-
cuits are in good condi-
tion.“PNK/BLK” wire open or
short
Poor C41-1 terminal con-
nection
If wire and connection are
OK, substitute a known-
good ECM and recheck.
NOTE:
When A/C evaporator thermistor temp. is below 2.5°C (36.5°F), A/C remain OFF (C41-1 terminal volt-
age become 0 – 1 V). This condition is not abnormal.

6-128 ENGINE GENERAL INFORMATION AND DIAGNOSIS
TABLE B-7 RADIATOR FAN CONTROL SYSTEM CHECK
INSPECTION
1. Radiator fan relay No.1 3. Radiator fan relay No.3 [A] : Case of TYPE A is shown (See NOTE)
2. Radiator fan relay No.2 4. Radiator fan [B] : Case of TYPE B is shown (See NOTE)
BATT
80A30A
15A
BLKBLU/WHT
ECM
BLK/ORN
BLK/ORNC42-1
C42-3
L+
L–
H– H+
BLU
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
C41-18
GRN/RED [B]PPL/YEL [A]
BLK/RED
BLU/WHT
BLU/RED
BLK
BLU
BLU/BLK
PPL/YEL
BLU/REDBLK/YEL
BRN/WHT
1
2
34
G02-3 [A]
C41-9 [B]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
Step Action Yes No
1 Check Fan Control System.
1) Connect scan tool to DLC with ignition switch OFF.
2) Start engine and select “DATA LIST” mode on scan
tool.
3) Warm up engine until coolant temp. is 97.5°C, 208°F or
higher and A/C switch turn OFF. (If engine coolant
temp. does not rise, check engine cooling system or
ECT sensor.) See Fig. 1.
Is radiator cooling fan started when engine coolant temp.
reached above temp.?Radiator cooling fan
control system is in
good condition.Go to Step 2.
2 Check Radiator Fan Relay and Its Circuit.
1) Check DTC and pending DTC with scan tool.
Is DTC P0480 displayed?Go to DTC P0480 Diag.
Flow Table.Go to Step 3.
3 Check Radiator Fan Relays.
1) Turn ignition switch OFF and remove radiator cooling
fan relays. (No.1 – No.3)
2) Check for proper connection to relay at terminals “c”
and “d”.
3) If OK, check that there is continuity between “c” and “d”
when battery is connected to terminals “a” and “b”. See
Fig. 2.
Is check result satisfactory?Go to Step 4. Replace radia-
tor fan relay(s).