2000 SUZUKI SWIFT ignition

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

6-114 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P1717 A/T DRIVE RANGE (PARK/NEUTRAL POSITION) SIGNAL CIRCUIT
MALFUNCTION
WIRING DIAGRAM / CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Start engine and shift selector lever to “D” range.
4) Increase vehicle speed to higher than 20 mph, 32 km/h and then stop vehicle.
5) Repeat above step 4) 9 times.
6) Shift selector lever to “2” range and repeat above step 4) and 5).
7) Shift selector lever to “L” range and repeat above step 4) and 5).
8) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
1. From ignition switch 2. Transmission range switch
[A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
TCMECMIG1
12V P
R
N
D
2
L
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
IG11
C44-8
REDGRN/ORN1
2G02-6 [B] C41-14 [A]
C41-15 [A]
G02-2 [B] GRN RED [B]LT BLU [A]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
DTC DETECTING CONDITION POSSIBLE CAUSE
“D” range signal not inputted (Park/Neutral position
signal inputted) to ECM while vehicle running
✱2 driving cycle detection logic, continuous monitor-
ing.“LT BLU” circuit open
Transmission range switch malfunction
“R”, “D”, “2” or “L” range signal circuit open
TCM power or ground circuit open
TCM malfunction
ECM malfunction
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.

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.

6-120 ENGINE GENERAL INFORMATION AND DIAGNOSIS
TABLE B-3 FUEL PRESSURE CHECK
WIRING DIAGRAM
INSPECTION
1. Injector (A) : Fuel pressure gauge
2. Delivery pipe (B) : Hose
3. Fuel pump (C) : Attachment
Step Action Yes No
1 Check Fuel Pressure (Refer to Section 6E for
details).
1) Release fuel pressure from fuel feed line.
2) Install fuel pressure gauge.
3) Check fuel pressure by repeating ignition
switch ON and OFF. See Fig. 1.
Is fuel pressure then 270 – 310 kPa (2.7 – 3.1
kg/cm
2, 38.4 – 44.0 psi)?Go to Step 2. Go to Step 4.
2
Is 250 kPa (2.5 kg/cm
2, 35.6 psi) or higher fuel
pressure retained for 1 minute after fuel pump
is stopped at Step 1?Normal fuel pressure. Go to Step 3.
3 Is there fuel leakage from fuel feed line hose,
pipe or their joint?Fuel leakage from hose,
pipe or joint.Faulty fuel pressure regu-
lator.
4 Was fuel pressure higher than spec. in Step 1? Faulty fuel pressure regu-
lator.Clogged fuel filter,
Restricted fuel feed hose
or pipe, Faulty fuel pump
or Fuel leakage from hose
connection in fuel tank.

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)

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.

6-126 ENGINE GENERAL INFORMATION AND DIAGNOSIS
TABLE B-6 ELECTRIC LOAD SIGNAL CIRCUIT CHECK
INSPECTION
1. Blower fan motor 3. Rear defogger 5. To A/C switch
2. Blower fan switch 4. Position lamp
[A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
IG2
M
ECM
PNK/BLUG02-13
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
RED/BLK [A]
IG11
+BB
43 25 1
C42-17 [A]
C41-17 [B] RED/YEL [B]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
Step Action Yes No
1 Is SUZUKI scan tool available? Go to Step 2. Go to Step 3.
2 Check Electric Load Signal Circuit.
1) Connect SUZUKI scan tool to DLC with igni-
tion switch OFF.
2) Start engine and select “DATA LIST” mode
on scan tool.
3) Check electric load signal under following
each condition. See Fig. 1 and Table 1.
Is check result satisfactory?Electric load signal circuit
is in good condition.“RED/BLK” (Case of
TYPE A. See NOTE) or
C41-17 (Case of TYPE B.
See NOTE) and/or “PNK/
BLU” circuit open or short,
Electric load diodes mal-
function or Each electric
load circuit malfunction.
3 Check Electric Load Signal Circuit.
1) Turn ignition switch ON.
2) Check voltage at each terminals C42-17
(Case of TYPE A. See NOTE) or C41-17
(Case of TYPE B. See NOTE) and G02-13
of ECM connector connected, under above
each condition. See Fig. 2 and Table 1.
Is each voltage as specified?Electric load signal circuit
is in good condition.“RED/BLK” (Case of
TYPE A. See NOTE) or
C41-17 (Case of TYPE B.
See NOTE) and/or “PNK/
BLU” circuit open or short,
Electric load diodes mal-
function or Each electric
load circuit malfunction.