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DTC P0121 Throttle Position Circuit Range / Performance Problem
WIRING DIAGRAM
Refer to DTC P0120 section.
CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
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. : –10 °C, 14 °F or higher
–Intake air temp. : 70 °C, 158 °F or lower
–Engine coolant temp. : 70 °C, 158 °F or higher
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.
INSPECTION
DTC DETECTING CONDITION POSSIBLE CAUSE
After engine warmed up.
Difference between actual throttle opening (detected from TP sensor)
and opening calculated by ECM (Obtained on the basis of engine
speed and intake manifold pressure) in larger than specified value.
✱2 driving cycle detection logic, continuous monitoringTP sensor malfunction
High resistance in the circuit
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, on a level road.
Step Action Yes No
1Was “Engine Diag. Flow Table” performed? 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 TP Sensor and Its Circuit.
1) Turn ignition switch OFF and connect
SUZUKI scan tool to DLC. See Fig. 1.
2) Turn ignition switch ON and check TP sen-
sor output voltage when throttle valve is at
idle position and fully opened. See Fig. 3.
Dose voltage vary within specified value linearly
as shown in figure?Substitute a known-good
ECM and recheck.Go to Step 5.
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[A] Fig. 1 for Step 3 / [B] Fig. 2 for Step 4 / [C] Fig. 3 for Step 3 and 4
Fig. 4 for Step 54 Check TP Sensor and its Circuit.
1) Turn ignition switch ON.
2) Check voltage at terminal E19-16 of ECM
connector connected, when throttle valve is
at idle position and fully opened. See Fig. 2
and 3.
Dose voltage vary within specified value linearly
as shown in figure?If voltmeter was used,
check terminal E19-16 for
poor connection.
If OK, substitute a known-
good ECM and recheck.Go to Step 5.
5 Check TP Sensor.
1) Turn ignition switch OFF.
2) Disconnect TP sensor connector.
3) Check for proper connection to TP sensor
at each terminal.
4) If OK, then measure resistance between
terminals and check if each measured value
is as specified below. See Fig. 4.
TP sensor resistance
Between 1 and 2 : 4.0 – 6.0 k
Ω
ΩΩ Ω
Between 1 and 3 : 0.02 – 6.0 k
Ω
ΩΩ Ω, varying
according to throttle valve opening.
Are measured values as specified?High resistance in “Lg/R”,
“Lg” or “B/Bl” circuit.
If wire and connection are
OK, substitute a known-
good ECM and recheck.Replace TP sensor. Step Action Yes No
[A] : When using SUZUKI scan tool.
[B] : When not using SUZUKI scan tool.
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DTC P0135 (DTC No.14) Heated Oxygen Sensor (HO2S) Heater Circuit Mal-
function (Sensor-1)
CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON, start engine and keep it at idle for 1 min.
3) Start vehicle and depress accelerator pedal fully for 5 sec. or longer.
4) Stop vehicle.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
1. Heated oxygen sensor-1 (HO2S-1) heater
DTC DETECTING CONDITION POSSIBLE CAUSE
DTC will set when A or B condition is met.
A :
Low voltage at terminal E19-7 when engine is running
at high load.
B :
High voltage at terminal E19-7 when engine is running
under condition other than above.
✱
✱✱ ✱2 driving cycle detection logic, Continuous monitoring.HO2S-1 heater circuit open or shorted to ground
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.
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INSPECTION
[A] Fig. 1 for Step 2 / [B] Fig. 2 for Step 3Step Action Yes No
1Was “Engine Diag. Flow Table” performed? Go to Step 2. Go to “Engine Diag. Flow
Table”.
2 Check Heater for Operation.
1) Check voltage at terminal E19-7. See Fig. 1.
2) Warm up engine to normal operating tem-
perature.
3) Stop engine.
4) Turn ignition switch ON and Check voltage
at terminal E19-7. See Fig. 1. Voltage
should be over 10 V.
5) Start engine, run it at idle and check voltage
at the same terminal. Voltage should be
below 1.9 V.
Are check results are specified?Intermittent trouble Check
for intermittent referring to
“Intermittent and Poor
Connection” in Section
0A.Go to Step 3.
3 Check Heater of Sensor-1.
1) Disconnect HO2S-1 coupler with ignition
switch OFF.
2) Check for proper connection to HO2S-1 at
“B/W” and “P/B” wire terminals.
3) If OK, then check heater resistance. See
Fig. 2.
Is it 5 – 6.4 Ω at 20 °C, 68 °F?“P/B” wire open or
shorted to ground or poor
connection at E19-7. If
wire and connection are
OK, substitute a known-
good ECM and recheck.Replace HO2S-1.
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DTC P0136 Heated Oxygen Sensor (HO2S) Circuit Malfunction (Sensor-2)
CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
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. : –10 °C, 14 °F or higher
–Intake air temp. : 70 °C, 158 °F or lower
–No exhaust gas leakage and loose connection
2) Warm up engine to normal operating temperature.
3) Drive vehicle under usual driving condition for 5 min. and check HO2S-2 output voltage and “short term fuel
trim” with “Data List” mode on scan tool, and write it down.
4) Stop vehicle (don’t turn ignition switch OFF).
5) Increase vehicle speed to higher than 20 mph, 32 km/h and then stop vehicle.
1. Heated oxygen sensor-2 (HO2S-2) [A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
NOTE:
For TYPE A and TYPE B, refer to the NOTE in “ECM Terminal Voltage Values Table” for applicable
model.
DTC DETECTING CONDITION POSSIBLE CAUSE
Engine is warmed up and HO2S-2 voltage is 4.5 V or more.
(circuit open)
✱
✱✱ ✱2 driving cycle detection logic, monitoring once / 1 driving.Exhaust gas leakage
“W” or “B/Bl” circuit open or short
Heated oxygen sensor-2 malfunction
Fuel system 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, on a level road.
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DTC P0141 Heated Oxygen Sensor (HO2S) Heater Circuit Malfunction (Sen-
sor-2)
CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF once and then ON.
2) Clear DTC, start engine and warm up engine to normal operating temperature.
3) Keep it at 2000 r/min for 2 min.
4) Check pending DTC in “ON BOARD TEST” or “PENDING DTC” mode and DTC in “DTC” mode.
DTC DETECTING CONDITION POSSIBLE CAUSE
DTC will set when A or B condition it met.
1) Low voltage at terminal E18-4 for specified time after
engine start or while engine running at high load.
2) High voltage at terminal E18-4 while engine running
under other than above condition.
✱
✱✱ ✱2 driving cycle detection logic, continuous monitoring.HO2S-2 heater circuit open or shorted to ground
ECM malfunction
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INSPECTION
Fig. 1 for Step 2Step Action Yes No
1Was “Engine Diag. Flow Table” performed? Go to Step 2. Go to “Engine Diag. Flow
Table”.
2 Check HO2S-2 Heater and Its Circuit.
1) Warm up engine to normal operating tem-
perature.
2) Stop engine.
3) Turn ignition switch ON and check voltage at
terminal E18-4. See Fig. 1. Voltage should
be over 10 V.
4) Start engine, run it at idle and check voltage
at the same terminal after 1 min. from
engine start.
Voltage should be below 1.9 V.
Are check result as specified?Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection” in
Section 0A.Go to Step 3.
3 Check Heater or Sensor-2.
1) Disconnect HO2S-2 coupler with ignition
switch OFF.
2) Check for proper connection to HO2S-2 at
“B/W” and “R/Bl” wire terminals.
3) If OK, then check heater for resistance.
Is it 11.7 – 14.3 Ω at 20 °C, 68 °F?“R/Bl” wire open or
shorted to ground or poor
connection at E18-4. If
wire and connection are
OK, substitute a known-
good ECM and recheck.Replace HO2S-2.
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5 Check Fuel Injectors and Circuit.
1) Using sound scope (4) or such, check operating
sound of each injector (5) when engine is run-
ning. Cycle of operating sound should vary
according to engine speed. See Fig. 3.
If no sound or an unusual sound is heard, check
injector circuit (wire or coupler) or injector.
2) Turn ignition switch OFF and disconnect a fuel
injector connector.
3) Check for proper connection to fuel injector at
each terminal.
4) If OK, then check injector resistance.
See Fig. 4.
Injector resistance
11.3 – 13.8 ohm at 20 °C (68 °F)
5) Carry out steps 1) and 3) on each injector.
6) Check each injector for injected fuel volume
referring to Section 6E. See Fig. 5.
Injected fuel volume
43 – 47 cc/15 sec (1.45/1.51 – 1.58/1.65 US/
Imp.oz/15 sec)
7) Check each injector for fuel leakage after injec-
tor closed.
Fuel leakage
Less than 1 drop / min. (1)
Is check result in step 1) and 3) to 7) satisfactory?Go to Step 6. Check injector circuit or
replace fuel injector(s).
6 Check EVAP Canister Purge Valve.
1) Disconnect purge hose (2) 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. 6.
Is vacuum felt?Check EVAP control
system (See Section
6E).Go to Step 7.
7 Check intake manifold absolute pressure sensor for
performance (See step 4) of DTC P0105 (No.11)
Diag. Flow Table).
Is it in good condition?Go to Step 8. Repair or replace.
8 Check engine coolant temp. sensor for perfor-
mance (See Section 6E).
Is it in good condition?Go to Step 9. Replace engine coolant
temp. sensor.
9 Check intake air temp. sensor for performance
(See Section 6E).
Is it in good condition?Go to Step 10. Replace intake air temp.
sensor.
10 Check throttle position sensor for performance
(See step 5) of DTC P0121 Diag. Flow Table).
Is it in good condition?Go to Step 11. Replace throttle position
sensor.
11 Check PCV valve for valve clogging
(See Section 6E).
Is it good condition?Substitute a known-
good ECM and recheck.Replace PCV valve. Step Action Yes No