ECM SUZUKI SWIFT 2000 1.G SF310 Service Owner's Guide

Main fuse Ignition switch
Main fuseMalfunction indicator lamp in combination meter
Relay box“IG COIL METER”
6-42 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
TABLE A-3 ECM (PCM) POWER AND GROUND CIRCUIT CHECK – MIL
DOESN’T LIGHT AT IGNITION SWITCH ON AND ENGINE DOESN’T
START THOUGH IT IS CRANKED UP
CIRCUIT DESCRIPTION
When the ignition switch tuned ON, the main relay turns ON (the contact point closes) and the main power is sup-
plied to ECM (PCM).
INSPECTION
STEPACTIONYESNO
1Main Relay Operating Sound Check
Is operating sound of main relay heard at ignition switch ON?Go to Step 5.Go to Step 2.
2Main Relay Check
1) Turn OFF ignition switch and remove main relay (1).
2) Check for proper connection to main relay (1) at terminal
3 and 4.
3) Check resistance between each two terminals. See Fig. 1
and 2.
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. See Fig. 3.
Is main relay in good condition?Go to Step 3.Replace main
relay.
3Fuse Check
Is main “FI” fuse in good condition?Go to Step 4.Check for short in
circuits connected
to this fuse.
4ECM (PCM) Power Circuit Check
1) Turn OFF ignition switch, disconnect connectors from ECM
(PCM) and install main relay.
2) Check for proper connection to ECM (PCM) at terminals
C03-20, C02-2, C02-15 and C02-22.
3) If OK, then measure voltage between terminal C03-20 and
ground, C02-22 and ground with ignition switch ON.
Is each voltage 10 – 14 V?Go to Step 5.“B/W”, “W/R” or
“Bl / B” circuit
open.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-43
Fig. 1 for Step 2 Fig. 2 for Step 2 Fig. 3 for Step 2
1. Main relay
2. Relay box
STEPACTIONYESNO
5ECM (PCM) Power Circuit Check
1) Using service wire, ground terminal C02-22 and
measure voltage between terminal C02-2 and
ground at ignition switch ON.
Is it 10 – 14 V?Check ground circuits
“Bl / B” and “W / Bl” for
open.
If OK, then substitute a
known-good ECM
(PCM) and recheck.Go to Step 6.
6Is operating sound of main relay heard in Step 1?Go to Step 7.“W / R” or “W / Bl” wire
open.
7Main Relay Check
1) Check main relay according to procedure in
Step 2.
Is main relay in good condition?“W / R” or “W / Bl” wire
open.Replace main relay.

MAP sensorTo TP sensor
To other sensors
6-44 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
DTC P0105 MANIFOLD ABSOLUTE PRESSURE (MAP) CIRCUIT
MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE

MAP: 5 kPa, 37.5 mmHg or less
(Low pressure – High vacuums – Low voltage)
or

MAP: 130 kPa, 975 mmHg or more
(High pressure – Low vacuums – High voltage)
“G” circuit open

“Lg” circuit open or shorted to ground

“Lg / R” circuit open or shorted to ground

MAP sensor malfunction

ECM (PCM) malfunction
NOTE:

When DTC P0105, and / or P0120, P0510 are indicated together, it is possible that “Lg” circuit is open.

When DTC P0105, P0110, P0115 and / or P0120 are indicated together, it is possible that “G” circuit is
open.
DTC CONFIRMATION PROCEDURE
1) Clear DTC, start engine and keep it at idle for 1 min.
2) Select “DTC” mode on scan tool and check DTC.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-45
Fig. 1 for Step 2 Fig. 2 for Step 3
Scan tool
DLC
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE”
performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check MAP Sensor and Its Circuit.
1) Connect scan tool to DLC with ignition
switch OFF.
2) Turn ignition switch ON.
3) Check intake manifold pressure.
See Fig. 1.
Is it 130 kPa or more or 5 kPa or less?Go to Step 3.Intermittent trouble.
Check for intermittent
referring to
“INTERMITTENT AND
POOR CONNECTION” in
Section 0A.
3Check Wire Harness.
1) Disconnect MAP sensor connector with
ignition switch OFF.
2) Check for proper connection of MAP
sensor at “Lg / R” and “G” wire
terminals.
3) If OK, then with ignition switch ON, check
voltage at each of “Lg” and “Lg / R” wire
terminals. See Fig. 2.
Is voltage about 4 – 6 V at each terminal?Go to Step 4.“Lg” wire open or
shorted to ground circuit or
shorted to power circuit,
“Lg / R” wire open or
shorted to ground, poor
C01-5 connection or
C01-1 connection.
If wire and connection are
OK, confirm that MAP
sensor is normal and then
substitute a known-good
ECM (PCM) and recheck.
NOTE: When battery
voltage is applied to
“Lg” wire, it is possible
that MAP sensor is also
faulty.
4Check MAP sensor according to “MAP
Sensor Individual Check” in Section 6E1.
Is it in good condition?“Lg” wire shorted to
“Lg / R” wire, “G” wire
open, poor C01-9
connection.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.Replace MAP sensor.

To other sensors IAT sensor
6-46 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
DTC P0110 INTAKE AIR TEMP. (IAT) CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE

Low intake air temperature (High voltage-High resistance)
or

High intake air temperature (Low voltage-Low resistance)
“Gr” circuit open or shorted to power

“G” circuit open

IAT sensor malfunction

ECM (PCM) malfunction
NOTE:

When DTC P0105, P0110, P0115 and P0120 are indicated together, it is possible that “G” circuit is open.

Before inspecting, be sure to check that ambient temperature is higher than –40C (–40F).
DTC CONFIRMATION PROCEDURE
1) Clear DTC, start engine and keep it at idle for 1 min.
2) Select “DTC” mode no scan tool and check DTC.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-47
Fig. 1 for Step 2 Fig. 2 for Step 3 Fig. 3 for Step 4
Scan tool
DLC
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check IAT Sensor and Its Circuit.
1) Connect scan tool to DLC with ignition switch
OFF.
2) Turn ignition switch ON.
3) Check intake air temp. displayed on scan tool.
See Fig. 1.
Is –40C (–40F) or 119C (246F) indicated?Go to Step 3.Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection”
in Section 0A.
3Check Wire Harness.
1) Disconnect IAT sensor connector with ignition
switch OFF.
2) Check for proper connection to IAT sensor at
“Gr” and “G” wire terminals.
3) If OK, then with ignition switch ON, is voltage
applied to “Gr” wire terminal about 4 – 6 V? See
Fig. 2.Go to Step 5.“Gr” wire open or
shorted to power, or
poor C01-14
connection.
If wire and connection
are OK, substitute a
known-good ECM
(PCM) and recheck.
4Does scan tool indicate –40C (–40F) at Step 2.Go to Step 6.Go to Step 5.
5Check Wire Harness.
1) Check intake air temp. displayed on scan tool
with ignition switch ON.
Is –40C (–40F) indicated?Replace IAT sensor.“Gr” wire shorted to
ground.
If wire is OK, substitute
a known-good ECM
(PCM) and recheck.
6Check Wire Harness.
1) Using service wire, connect IAT sensor
connector terminals.
2) Check intake air temp. displayed on scan tool
with ignition switch ON. See Fig. 3.
Is 119C (246F) indicated?Replace IAT sensor.“Gr” wire open or poor
C01-9 connection.
If wire and connection
are OK, substitute a
known-good ECM
(PCM) and recheck.

ECT sensor
To combination
(ECT) meterTo other sensors
6-48 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
DTC P0115 ENGINE COOLANT TEMPERATURE (ECT) CIRCUIT
MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE

Low engine coolant temperature (High voltage-High resistance)
or

High engine coolant temperature (Low voltage-Low resistance)
“Gr / W” circuit open or shorted to power

“G” circuit open

ECT sensor malfunction

ECM (PCM) malfunction
NOTE:
Before inspecting, be sure to check that coolant temp. meter in combination meter indicates normal oper-
ating temperature (Engine is not overheating).
DTC CONFIRMATION PROCEDURE
1) Clear DTC, start engine and keep it at idle for 1 min.
2) Select “DTC” mode on scan tool and check DTC.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-49
Fig. 1 for Step 2 Fig. 2 for Step 3 Fig. 3 for Step 4
Scan tool
DLC
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check ECT Sensor and Its Circuit.
1) Connect scan tool with ignition switch OFF.
2) Turn ignition switch ON.
3) Check engine coolant temp. displayed on scan
tool. See Fig. 1.
Is –40C (–40F) or 119C (246F) indicated?Go to Step 3.Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection”
in Section 0 A.
3Check Wire Harness.
1) Disconnect ECT sensor connector.
2) Check engine coolant temp. displayed on scan
tool.
Is –40C (–40F) indicated?Replace ECT sensor.“Gr / W” wire shorted to
ground.
If wire is OK, substitute
a known-good ECM
(PCM) and recheck.
4Does scan tool indicate –40C (–40F) at Step 2.Go to Step 6.Go to Step 5.
5Check Wire Harness.
1) Disconnect ECT sensor connector with
ignition switch OFF.
2) Check for proper connection to ECT sensor at
“G” and “Gr / W” wire terminals.
3) If OK, then with ignition switch ON, is voltage
applied to “G” wire terminal about 4 – 6 V?
See Fig. 2.Go to Step 4.“Gr / W” wire open or
shorted to power, or
poor C01-7 connection.
If wire and connection
are OK, substitute a
known-good ECM
(PCM) and recheck.
6Check Wire Harness.
1) Using service wire, connect ECT sensor
connector terminals. See Fig. 3.
2) Turn ignition switch ON and check engine
coolant temp. displayed on scan tool.
Is 119C (246F) indicated?Replace ECT sensor.“G” wire open or
poor C01-9 connection.
If wire and connection
are OK, substitute a
known-good ECM
(PCM) and recheck.

To other sensors Throttle
position
sensorTo other sensors
6-50 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
DTC P0120 THROTTLE POSITION CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE

Signal voltage high
or

Signal voltage low
“G” circuit open

“Lg / W” circuit open or shorted to ground

“Lg” circuit open or shorted to power or ground

TP sensor malfunction

ECM (PCM) malfunction
NOTE:

When DTC P0105, P0110, P0115 and / or P0120 are indicated together, it is possible that “G” circuit is
open.

When DTC P0105, P0120 and / or P0510 are indicated together it is possible that “Lg” circuit is open.
DTC CONFIRMATION PROCEDURE
1) Clear DTC, start engine and keep it at idle for 1 min.
2) Select “DTC” mode on scan tool and check DTC.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-51
Fig. 1 for Step 2 Fig. 2 for Step 3 Fig. 3 for Step 4
Scan tool
“Lg” “Lg/W”
“3”“4”
“1”
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE”
performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check TP Sensor and Its Circuit.
1) Connect scan tool to DLC with ignition
switch OFF and then turn ignition switch
ON.
2) Check throttle valve opening percentage
displayed on scan tool. See Fig. 1.
Is it displayed 2% or less?
3) Check throttle valve opening percentage
displayed on scan tool while opening
throttle valve from idle position to full open
position. See Fig. 1.
Is it displayed 96% or higher?Go to Step 3.Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection” in
Section 0 A.
3Check Wire Harness.
1) Disconnect connector from TP sensor
with ignition switch OFF.
2) Check for proper connection to TP sensor
at “Lg”, “Lg/W” and “G” wire terminal.
3) If OK, then with ignition switch ON, check
voltage at each of “Lg” and “Lg / W” wire
terminals. See Fig. 2.
Is voltage about 4 – 6 V at each terminal?Go to Step 4.“Lg” wire open, “Lg”
wire shorted to ground
circuit or power circuit or
“G” wire, “Lg / W” wire
open or shorted to ground
circuit or poor C01-1 or
C01-6 connection.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.
4Check TP Sensor.
1) Check resistance between terminals of
TP sensor. See Fig. 3.
Between 1 and 4: 2.87 – 5.33 kΩ
Between 1 and 3: 100 Ω – 20 kΩ, varying
according to throttle valve opening.
Are measured values within specifications?“G” wire open or poor
C01–9 connection.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.Replace TP sensor.