
EC-226
< SERVICE INFORMATION >
DTC P0133 A/F SENSOR 1
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
 WITH CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1minute under no load.
4. Let engine idle for 1 minute.
5. Select “A/F SEN1(B1) P1278/P1279” of “A/F SEN1” in “DTC WORK SUPPORT” mode with CONSULT-II.
6. Touch “START”.
If “COMPLETED” appears on CONSULT-II screen, go to step
10.
If “COMPLETED” does not appear on CONSULT-II screen, go to
the following step.
7. After perform the following procedure, “TESTING” will be dis-
played on the CONSULT-II screen.
a. Increase the engine speed up to 4,000 to 5,000 rpm and keep it
for 10 seconds.
b. Fully release accelerator pedal and then let engine idle for about
10 seconds.
If “TESTING” is not displayed after 10 seconds, refer to EC-
127.
8. Wait for about 20 seconds at idle at under the condition that
“TESTING” is displayed on the CONSULT-II screen.
9. Make sure that “TESTING” changes to “COMPLETED”.
If “TESTING” changed to “OUT OF CONDITION”, refer to
EC-127
. 
10. Make sure that “OK” is displayed after touching “SELF-DIAG
RESULT”.
If “NG” is displayed, go to EC-229, "
Diagnosis Procedure".
 WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Select Service $01 with GST.
3. Calculate the total value of “Short term fuel trim” and “Long term fuel trim” indications.
Make sure that the total percentage should be within ±15%.
If OK, go to the following step.
If NG, check the following.
• Intake air leaks
• Exhaust gas leaks
• Incorrect fuel pressure
PBIB0756E
PBIB1925E
PBIB0758E 

DTC P0137 HO2S2
EC-233
< SERVICE INFORMATION >
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DTC P0137 HO2S2
Component DescriptionINFOID:0000000001702733
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas.
Even if switching characteristics of the air fuel ratio (A/F) sensor 1
are shifted, the air/fuel ratio is controlled to stoichiometric, by the sig-
nal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000001702734
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000001702735
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the air fuel ratio (A/F) sensor 1. The oxy-
gen storage capacity before the three way catalyst (manifold) causes
the longer switching time. To judge the malfunctions of heated oxy-
gen sensor 2, ECM monitors whether the maximum voltage of the
sensor is sufficiently high during the various driving condition such
as fuel-cut.
DTC Confirmation ProcedureINFOID:0000000001702736
NOTE:
If DTC confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
 WITH CONSULT-II
TESTING CONDITION:
For the best results, perform DTC WORK SUPPORT at a temperature of 0 to 30°C (32 to 86°F).
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2  (B1) • Revving engine from idle to 3,000 rpm quickly after the following 
conditions are met.
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 
minute and at idle for 1 minute under no load0 - 0.3V ←→ Approx. 0.6 - 1.0V
HO2S2 MNTR (B1) LEAN ←→ RICH
SEF259VA
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0137
0137Heated oxygen sensor 2 cir-
cuit low voltageThe maximum voltage from the sensor is not 
reached to the specified voltage.• Harness or connectors
(Heated oxygen sensor 2 circuit open or 
shorted.)
• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector
• Intake air leaks 

DTC P0138 HO2S2
EC-241
< SERVICE INFORMATION >
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DTC Confirmation ProcedureINFOID:0000000001702745
Perform PROCEDURE FOR MALFUNCION A first.
If DTC cannot be confirmed, perform PROCEDURE FOR MALFUNCTION B.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
PROCEDURE FOR MALFUNCTION A
 With CONSULT-II
1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-II.
2. Start engine and warm it up to the normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and keep the engine speed between 3,500 and
4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 2 minutes.
6. If 1st trip DTC is detected, go to EC-244, "
Diagnosis Procedure".
 With GST
Follow the procedure “With CONSULT-II” above.
PROCEDURE FOR MALFUNCTION B
 With CONSULT-II
TESTING CONDITION:
For the best results, perform DTC WORK SUPPORT at a temperature of 0 to 30°C (32 to 86°F).
1. Turn ignition switch ON and select “DATA MONITOR ” mode
with CONSULT-II 
2.  Start engine and warm it up to the normal operating tempera-
ture.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and keep the engine speed between 3,500 and
4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.
6. Make sure that “COOLAN TEMP/S” indicates more than 70°C
(158°F).
If not, warm up engine and go to next step when “COOLAN
TEMP/S” indication reaches to 70°C (158°F).
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0138
0138Heated oxygen sensor 2 
circuit high voltageA)An excessively high voltage from the 
sensor is sent to ECM.• Harness or connectors
(Heated oxygen sensor 2 circuit is open 
or shorted.)
• Heated oxygen sensor 2
B)The minimum voltage from the sensor 
is not reached to the specified voltage.• Harness or connectors
(Heated oxygen sensor circuit is open or 
shorted.)
• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector
SEF174Y
SEF174Y 

EC-250
< SERVICE INFORMATION >
DTC P0139 HO2S2
DTC P0139 HO2S2
Component DescriptionINFOID:0000000001702751
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas.
Even if switching characteristics of the air fuel ratio (A/F) sensor 1
are shifted, the air/fuel ratio is controlled to stoichiometric, by the sig-
nal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000001702752
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000001702753
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the air fuel ratio (A/F) sensor 1. The oxy-
gen storage capacity before the three way catalyst (manifold) causes
the longer switching time. To judge the malfunctions of heated oxy-
gen sensor 2, ECM monitors whether the switching response of the
sensor's voltage is faster than specified during the various driving
condition such as fuel-cut.
DTC Confirmation ProcedureINFOID:0000000001702754
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
 WITH CONSULT-II
TESTING CONDITION:
For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30 °C (32 to 86 °F).
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1) • Revving engine from idle to 3,000 rpm quickly after the following condi-
tions are met.
- Engine: After warming up
- Keep the engine speed between 3,500 rpm and 4,000 rpm for 1 minute 
and idle for 1 minute under no load0 - 0.3V ←→ Approx. 0.6 - 1.0V
HO2S2 MNTR (B1)LEAN ←→ RICH
SEF302U
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0139
0139Heated oxygen sensor 2 
circuit slow responseIt takes more time for the sensor to respond be-
tween rich and lean than the specified time.• Harness or connectors
(Heated oxygen sensor circuit is open or 
shorted.)
• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector
• Intake air leaks 

DTC P0171 FUEL INJECTION SYSTEM FUNCTION
EC-257
< SERVICE INFORMATION >
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DTC P0171 FUEL INJECTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000001702760
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the air fuel ratio (A/F) sensor 1. The
ECM calculates the necessary compensation to correct the offset between the actual and the theoretical
ratios. In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.),
the ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection
logic).
DTC Confirmation ProcedureINFOID:0000000001702761
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
 WITH CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-II.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Select “DATA MONITOR” mode with CONSULT-II.
6. Start engine again and let it idle for at least 10 minutes.
The 1st trip DTC P0171 should be detected at this stage, if a
malfunction exists. If so, go to EC-260, "
Diagnosis Procedure".
NOTE:
If 1st trip DTC is not detected during above procedure, perform-
ing the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar conditions to
(1st trip) Freeze Frame Data for 10 minutes. Refer to the table
below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following con-
ditions should be satisfied at the same time.
Sensor Input Signal to ECM ECM function Actuator
Air fuel ratio (A/F) sensor 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)Fuel injection control Fuel injector
DTC No.Trouble diagnosis 
nameDTC detecting condition Possible cause
P0171
0171Fuel injection system 
too lean• Fuel injection system does not operate properly.
• The amount of mixture ratio compensation is too 
large. (The mixture ratio is too lean.)• Intake air leaks
• Air fuel ratio (A/F) sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Mass air flow sensor
• Incorrect PCV hose connection
SEF215Z
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH) 

DTC P0171 FUEL INJECTION SYSTEM FUNCTION
EC-261
< SERVICE INFORMATION >
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1. Listen for an intake air leak after the mass air flow sensor.
2. Check PCV hose connection.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace.
3.CHECK AIR FUEL RATIO (A/F) SENSOR 1 CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect air fuel ratio (A/F) sensor 1 harness connector (1).
- Air fuel ratio (A/F) sensor 1 (2)
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals.
Refer to Wiring Diagram.
5. Check harness continuity between ECM terminals 49, 53 or A/F sensor 1 terminals 1, 2 and ground.
Refer to Wiring Diagram.
6. Also check harness for short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-78, "
Fuel Pressure Check".
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-78, "
Fuel Pressure Check".
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
• Fuel pump and circuit (Refer to EC-526
.)
• Fuel pressure regulator (Refer to EC-78, "
Fuel Pressure Check".)
• Fuel lines (Refer to EM-33
.)
• Fuel filter for clogging
>> Repair or replace.
6.CHECK MASS AIR FLOW SENSOR
 With CONSULT-II
1. Install all removed parts.
2. Start engine and warm it up to normal operating temperature. 
3. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-II.
 With GST
A/F sensor 1 terminal ECM terminal
149
253
Continuity should exist.
Continuity should not exist.
BBIA0699E
At idling: Approximately 350 kPa (3.57 kg/cm2, 51 psi)
at idling : 1.0 - 4.0 g·m/sec
at 2,500 rpm : 2.0 - 10.0 g·m/sec 

EC-264
< SERVICE INFORMATION >
DTC P0172 FUEL INJECTION SYSTEM FUNCTION
DTC P0172 FUEL INJECTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000001702764
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the air fuel ratio (A/F) sensor 1. The
ECM calculates the necessary compensation to correct the offset between the actual and the theoretical
ratios. In case the amount of the compensation value is extremely large (The actual mixture ratio is too rich.),
the ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection
logic).
DTC Confirmation ProcedureINFOID:0000000001702765
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
 WITH CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-II.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Select “DATA MONITOR” mode with CONSULT-II.
6. Start engine again and let it idle for at least 10 minutes.
The 1st trip DTC P0172 should be detected at this stage, if a
malfunction exists. If so, go to EC-267, "
Diagnosis Procedure".
NOTE:
If 1st trip DTC is not detected during above procedure, perform-
ing the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar conditions to
(1st trip) Freeze Frame Data for 10 minutes. Refer to the table
below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following con-
ditions should be satisfied at the same time.
Sensor Input Signal to ECM ECM function Actuator
Air fuel ratio (A/F) sensor 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)Fuel injection control Fuel injector
DTC No.Trouble diagnosis 
nameDTC detecting condition Possible cause
P0172
0172Fuel injection system 
too rich• Fuel injection system does not operate properly.
• The amount of mixture ratio compensation is too 
large. (The mixture ratio is too rich.)• Air fuel ratio (A/F) sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Mass air flow sensor
SEF215Z
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH) 

EC-268
< SERVICE INFORMATION >
DTC P0172 FUEL INJECTION SYSTEM FUNCTION
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace.
3.CHECK AIR FUEL RATIO (A/F) SENSOR 1 CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect air fuel ratio (A/F) sensor 1 harness connector (1).
- Air fuel ratio (A/F) sensor 1 (2)
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals. 
Refer to Wiring Diagram.
5. Check harness continuity between ECM terminals 49, 53 or A/F sensor 1 terminals 1, 2 and ground.
Refer to Wiring Diagram.
6. Also check harness for short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-78, "
Fuel Pressure Check".
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-78, "
Fuel Pressure Check".
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
• Fuel pump and circuit (Refer to EC-526
.)
• Fuel pressure regulator (Refer to EC-78, "
Fuel Pressure Check".)
>> Repair or replace.
6.CHECK MASS AIR FLOW SENSOR
 With CONSULT-II
1. Install all removed parts.
2. Start engine and warm it up to normal operating temperature.
3. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-II.
 With GST
1. Install all removed parts.
2. Start engine and warm it up to normal operating temperature.
3. Check mass air flow sensor signal in Service $01 with GST.
A/F sensor 1 terminal ECM terminal
149
253
Continuity should exist.
Continuity should not exist.
BBIA0699E
At idling: Approximately 350 kPa (3.57 kg/cm2, 51 psi)
at idling : 1.0 - 4.0 g·m/sec
at 2,500 rpm : 2.0 - 10.0 g·m/sec