2000 SUZUKI SWIFT engine

6-106 ENGINE GENERAL INFORMATION AND DIAGNOSIS
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 Idle Air Control System.
1) Connect SUZUKI scan tool to DLC with igni-
tion switch OFF, set parking brake and
block drive wheels.
2) Warm up engine to normal operating tem-
perature.
3) Clear DTC and select “MISC TEST” mode
on SUZUKI scan tool. See Fig. 1.
Is it possible to control (increase and reduce)
engine idle speed by using SUZUKI scan tool? Intermittent trouble or
faulty ECM.
Check for intermittent
referring to “Intermittent
and Poor Connection” in
Section 0A.Go to Step 5.
4 Check Idle Air Control System.
1) Remove IAC valve from throttle body refer-
ring to “IAC Valve Removal” in Section 6E1.
2) Check IAC valve for operation referring to
“IAC Valve Inspection” in Section 6E1. See
Fig. 2.
Is check result satisfactory?Intermittent trouble or
faulty ECM.
Check for intermittent
referring to “Intermittent
and Poor Connection” in
Section 0A.Go to Step 5.
5 Check Wire Harness for open and short.
1) Turn ignition switch OFF.
2) Disconnect IAC valve connector.
3) Check for proper connection to IAC valve at
each terminals.
4) If OK, disconnect ECM connector.
5) Check for proper connection to ECM at
C42-6 terminal.
6) If OK, check “BLK/RED”, “GRN/RED” and
“BLK” circuit for open and short.
Are they in good condition?Replace IAC valve and
recheck.Repair or replace.
[A] : When using SUZUKI scan tool:[ A]

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-107
Fig. 2 for Step 4
[A] : Without using SUZUKI scan tool:

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)

6-110 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P1500 ENGINE STARTER SIGNAL CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
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
1. Ignition switch 2. Transmission range switch (A/T) 3. Starter motor
[A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
321
BLK/YEL
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
ECM
C41-7 [A]
C41-20 [B]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
DTC DETECTING CONDITION POSSIBLE CAUSE
Low voltage at terminal C41-7 (Case of TYPE A. See
NOTE) or C41-20 (Case of TYPE B. See NOTE) when
cranking engine or
High voltage at terminal C41-7 (Case of TYPE A. See
NOTE) or C41-20 (Case of TYPE B. See NOTE) after
starting engine.
✱2 driving cycle detection logic, continuous monitoring.“BLK/YEL” circuit open
ECM malfunction
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Check Terminal Voltage.
1) Check for voltage at terminal C41-7 (Case of
TYPE A. See NOTE) or C41-20 (Case of
TYPE B. See NOTE) of ECM connector con-
nected, under following condition.
While engine cranking : 6 – 10 V
After starting engine : 0 V
Is voltage as specified?Poor C41-7 (Case of TYPE A. See
NOTE) or C41-20 (Case of TYPE B.
See NOTE)
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 and
recheck.“BLK/YEL” circuit open.

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-111
DTC P1510 ECM BACK-UP POWER SUPPLY MALFUNCTION
WIRING DIAGRAM / CIRCUIT DESCRIPTION
Battery voltage is supplied so that diagnostic trouble code memory, values for engine control learned by ECM,
etc. are kept in ECM even when the ignition switch is turned OFF.
DTC CONFIRMATION PROCEDURE
1) Clear DTC, start engine and run it at idle for 1 min.
2) Select “DTC” mode on scan tool and check DTC.
INSPECTION
[A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
WHT/RED
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
ECM
G02-17 [A]C41-7 [B]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
DTC DETECTING CONDITION POSSIBLE CAUSE
Low voltage at terminal G02-17 (Case of TYPE A.
See NOTE) or C41-7 (Case of TYPE B. See NOTE)
after starting engine.“WHT/RED” circuit open
ECM malfunction
Step Action Yes No
1 Check Terminal Voltage.
1) Check for voltage at terminal G02-17 (Case
of TYPE A. See NOTE) or C41-7 (Case of
TYPE B. See NOTE) of ECM connector
connected, under each condition, ignition
switch OFF and engine running.
Is it 10 – 14 V at each condition?Poor G02-17 (Case of
TYPE A. See NOTE) or
C41-7 (Case of TYPE B.
See NOTE) 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 and
recheck.“WHT/RED” circuit open.

6-112 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P1600 SERIAL COMMUNICATION PROBLEM BETWEEN ECM AND TCM
WIRING DIAGRAM
CIRCUIT DESCRIPTION
The serial data line is pulled up to about 12 V by ECM and TCM transmits information to ECM through it by con-
trolling its grounding.
TCM constantly sends information while ignition switch is ON as to whether judgement was made or not with
respect to all detectable DTCs as well as whether or not abnormality exists after judgement.
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Start engine and run it at idle for 1 min.
4) Select “DTC” mode on scan tool and check DTC.
INSPECTION
ECM
TCMIG1
BLK/WHT
12V
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
C44-20
C41-23
DTC DETECTING CONDITION POSSIBLE CAUSE
No signal inputted from TCM to ECM or check sum
error while engine running“BLK/WHT” circuit open or short
TCM power or ground circuit open
TCM malfunction
ECM malfunction
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Check Signal Voltage.
Check voltage between terminal C41-23 and
body ground with ignition switch ON.
Does it change between 0 – 12 V? See Fig. 1.Intermittent trouble or
faulty ECM or TCM.
Check for intermittent
trouble referring to “Inter-
mittent and poor connec-
tion” in Section 0A.Go to Step 3.

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-113
Fig. 1 for Step 2
Fig. 2 for Step 43 Is it about 12 V at Step 2?“BLK/WHT” wire open,
poor C44-20 connection
or TCM power or ground
circuit open. If wires and
connections are OK, sub-
stitute a known-good
TCM and recheck.Go to Step 4.
4 Check Signal Circuit.
1) Disconnect TCM coupler with ignition switch
OFF.
2) Check voltage between C44-20 terminal
and body ground with ignition switch ON.
See Fig. 2.
Is it about 12 V?Check TCM power and
ground circuit for open. If
OK, substitute a known-
good TCM and recheck.“BLK/WHT” wire shorted
to ground or poor C44-23
terminal connection.
If wire and connection are
OK, substitute a known-
good ECM and recheck. Step Action Yes No