2000 SUZUKI SWIFT Coolant

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
6-52 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
DTC P0121 THROTTLE POSITION CIRCUIT RANGE / PERFORMANCE
PROBLEM
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE

After engine warmed up.

While vehicle running at specified engine speed.

No change in intake manifold pressure (constant throttle opening)

Difference between actual throttle opening (detected from TP sensor)
and opening calculated by ECM (PCM) (Obtained on the basis of
engine speed and intake manifold pressure) in larger than specified
value.
2 driving cycle detection logic, continuous monitoring
TP sensor malfunction

High resistance in the circuit

ECM (PCM) malfunction
DTC CONFIRMATION PROCEDURE
WARNING:

When performing a road test, select a place where there is no traffic or possibility of a traffic accident
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.
1) Turn ignition switch OFF. Clear DTC with ignition switch ON, check vehicle and environmental condition for:
–Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Ambient temp.: –10C, 14F or higher
–Intake air temp.: 70C, 158F or lower
–Engine coolant temp.: 70 – 11 0C, 158 – 230F
2) Warm up engine to normal operating temperature.
3) Increase vehicle speed to 30 – 40 mph, 50 – 60 km / h in 3rd gear or “D” range and hold throttle valve at that
opening position for 1 min.
4) Stop vehicle.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-67
Fig. 1 for Step 3 Fig. 2 for Step 4 Fig. 3 for Step 5
Fig. 4 for Step 6
1. Throttle body
2. Fuel feed hose
GoodNo good
STEPACTIONYESNO
8Check engine coolant temp. sensor for performance
(See Section 6E1).
Is it in good condition?Go to Step 9.Replace engine
coolant temp. sensor.
9Check intake air temp. sensor for performance
(See Section 6E1).
Is it in good condition?Go to Step 10.Replace intake air
temp. sensor.
10Check throttle position sensor for performance (See
Step 4 of DTC P0121 Diag. Flow Table).
Is it in good condition?Go to Step 11.Replace throttle
position sensor.
11Check PCV valve for valve clogging (See Section
6E1).
Is it good condition?Substitute a known-
good ECM (PCM) and
recheck.Replace PCV valve.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-69
Below
specified value DTC DETECTING CONDITION
POSSIBLE CAUSE

Engine under other than high revolution condition

Not on rough road

Engine speed changing rate

Manifold absolute
pressure changing rate

Throttle opening changing rate

Misfire rate per 200 or 1000 engine revolutions (how
much and how often crankshaft revolution speed
changes) is higher than specified value
Engine overheating

Vacuum leaks (air inhaling) from air intake system

Ignition system malfunction (spark plug(s), high-
tension cord(s), ignition coil assembly)

Fuel pressure out of specification

Fuel injector malfunction (clogged or leakage)

Engine compression out of specification

Valve lash (clearance) out of specification

Manifold absolute pressure sensor malfunction

Engine coolant temp. sensor malfunction

PCV valve malfunction

EVAP control system malfunction
DTC CONFIRMATION PROCEDURE
WARNING:

When performing a road test, select a place where there is no traffic or possibility of a traffic accident
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.
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Check vehicle and environmental condition for:
–Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Ambient temp.: –10C, 14F or higher
–Intake air temp.: 70C, 158F or lower
–Engine coolant temp.: –10 – 11 0C, 14 – 230F
4) Start engine and keep it at idle for 2 min. or more.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
6) If DTC is not detected at idle, consult usual driving based on information obtained in “Customer complaint analy-
sis” and “Freeze frame data check”.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-71
1. Throttle body
2. Fuel feed hose
GoodNo good1. Injector connector
STEPACTIONYESNO
6Check PCV valve for clogging (See Section 6E1).
Is it in good condition?Go to Step 7.Replace PCV valve.
7Check EVAP Canister Purge Valve for Closing.
1) Disconnect purge hose (1) from EVAP canister.
2) Place finger against the end of disconnected hose.
3) Check that vacuum is not felt there, when engine is
cool and running at idle. See Fig. 5.
Is vacuum felt?Check EVAP
control system
(See Section 6E1).Go to Step 8.
8Check intake manifold pressure sensor for performance
(See Section 6E1).
Is it in good condition?Go to Step 9.Repair or replace.
9Check engine coolant temp. sensor for performance
(See Section 6E1).
Is it in good condition?Go to Step 10.Replace engine
coolant temp.
sensor.
10Check parts or system which can cause engine rough
idle or poor performance.
–Engine compression (See Section 6A).
–Valve lash (See Section 6A).
–Valve timing (Timing belt installation. See Section 6A).
Are they in good condition?Check wire harness
and connection of
ECM (PCM) ground,
ignition system and
fuel injector for
intermittent open
and short.Repair or replace.
Fig. 1 for Step 3 Fig. 2 for Step 3 Fig. 3 for Step 4
Fig. 4 for Step 5 Fig. 5 for Step 7

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-77
1) 2) 3) 4) 35 – 45 mph
(55 – 65 km / h)
30 – 40 mph
(50 – 60 km / h)
DTC CONFIRMATION PROCEDURE
WARNING:

When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and be very careful during testing to avoid occurrence of an accident.

Road test should be carried out with 2 persons, a driver and tester, on a level road.
1) Turn ignition switch OFF.
Clear DTC with ignition switch ON, check vehicle and environmental condition for:
–Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Ambient temp.: –10C, 14F or higher
–Intake air temp.: 70C, 158F or lower
–Engine coolant temp.: 70 – 11 0C, 158 – 230F
2) Start engine and drive vehicle at 40 – 47 mph, 65 – 75 km / h for 15 min. or longer.
While this driving, if “Catalyst Monitoring TEST COMPLETED” is displayed in “READINESS TESTS” mode and
DTC is not displayed in “DTC” mode, confirmation test is completed.
If “TEST NOT COMPLTD” is still being displayed, continue test driving.
3) Decrease vehicle speed at 28 – 34 mph, 45 – 55 km / h, and hold throttle valve at that opening position for 2 min.
and confirm that short term fuel trim vary within –20% –+20% range.
4) Stop vehicle (do not turn ignition switch OFF) and confirm test results according to following “Test Result Con-
firmation Flow Table”.
Test Result Confirmation Flow Table
STEPACTIONYESNO
1Check DTC in “DTC” mode and pending DTC in
“ON BOARD TEST” or “PENDING DTC” mode.
Is DTC or pending DTC displayed?Proceed to applicable
DTC Diag. Flow Table.Go to Step 2.
2Set scan tool to “READINESS TESTS” mode and
check if testing has been completed.
Is test completed?No DTC is detected
(confirmation test is
completed).Repeat DTC
confirmation
procedure.

6-80 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
Fig. 1 for Step 1
Main
fuseIgnition switch“IG COIL METER”
Radiator fan
relay
Radiator fan motor
DTC P0480 RADIATOR FAN CONTROL SYSTEM MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE

Low voltage at terminal C02-20 when engine coolant
temp. is below 91C, 195F.
2 driving cycle detection logic, continuous monitoring.
“B/W” or “BI” circuit open or short

Radiator fan relay malfunction

ECM (PCM) malfunction
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Warm up engine until radiator cooling fan starts to operate.
4) Check pending DTC in “ON BOARD TEST” or “PENDING DTC” mode and DTC in “DTC” mode.