Page 309 of 720

DTC P0138, P0158 HO2S2
EC-309
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Revision: 2006 November2007 350Z
2. CLEAR THE SELF-LEARNING DATA
With CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CONSULT-III.
3. Clear the self-learning control coefficient by touching “CLEAR”.
4. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0172 or P0175 detected?
Is it difficult to start engine?
Without CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
3. Disconnect mass air flow sensor (bank 1) harness connector, and restart and run engine for at least 5 sec-
onds at idle speed.
4. Stop engine and reconnect mass air flow sensor (bank 1) harness connector.
5. Make sure DTC P0102 is displayed.
6. Erase the DTC memory. Refer to EC-61, "
HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFOR-
MATION" .
7. Make sure DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0172 or P0175 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0172, P0175. Refer to EC-334, "DTC P0172, P0175 FUEL
INJECTION SYSTEM FUNCTION" .
No >> GO TO 3.
1. Mass air flow sensor (with intake air
temperature sensor) (bank 1)2. Mass air flow sensor (with intake air
temperature sensor) (bank 2)
PBIB3501E
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EC-310
DTC P0138, P0158 HO2S2
Revision: 2006 November2007 350Z
3. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 2 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between HO2S2 terminal 1 and ECM terminal 84.
Refer to Wiring Diagram.
5. Also check harness for short to ground and 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 HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal and HO2S2 terminal as follows.
Refer to Wiring Diagram.
2. Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.
3. Also check harness for short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
1. Heated oxygen sensor 2 (bank 2) 2. Heated oxygen sensor 2 (bank 2)
harness connector3. Heated oxygen sensor 2 (bank 1)
4. Heated oxygen sensor 2 (bank 1)
harness connector
:Vehicle front
Continuity should exist.
PBIB3502E
DTCTerminals
Bank
ECM Sensor
P0138 76 4 1
P0158 80 4 2
Continuity should exist.
DTCTerminals
Bank
ECM Sensor
P0138 76 4 1
P0158 80 4 2
Continuity should not exist.
Page 313 of 720

DTC P0139, P0159 HO2S2
EC-313
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DTC P0139, P0159 HO2S2PFP:226A0
Component DescriptionNBS0006R
The heated oxygen sensor 2, after three way catalyst 1, monitors the
oxygen level in the exhaust gas on each bank.
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-III Reference Value in Data Monitor ModeNBS0006S
Specification data are reference values.
On Board Diagnosis LogicNBS0006T
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 1 causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the switching response of the sen-
sor's voltage is faster than specified during the various driving condi-
tion such as fuel-cut.
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)
Revving engine from idle to 3,000 rpm quickly after the following condi-
tions 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)
HO2S2 MNTR(B2)
Revving engine from idle to 3,000 rpm quickly after the following condi-
tions 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 loadLEAN ←→ RICH
SEF302U
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0139
0139
(Bank 1)
Heated oxygen sensor
2 circuit slow responseIt takes more time for the sensor to respond
between rich and lean than the specified time.
Harness or connectors
(The sensor circuit is open or shorted)
Heated oxygen sensor 2
Fuel pressure
Fuel injector
Intake air leaks P0159
0159
(Bank 2)
Page 315 of 720
DTC P0139, P0159 HO2S2
EC-315
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Revision: 2006 November2007 350Z
Wiring DiagramNBS006UU
BANK 1
TBWT1634E
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EC-316
DTC P0139, P0159 HO2S2
Revision: 2006 November2007 350Z
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
17 PHeated oxygen sensor 2
heater (bank 1)[Engine is running]
Engine speed: Below 3,600 rpm 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 load.0 - 14V
[Ignition switch: ON]
Engine stopped
[Engine is running]
Engine speed: Above 3,600 rpmBATTERY VOLTAGE
(11 - 14V)
76 W/RHeated oxygen sensor 2
(bank 1)[Engine is running]
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 load.0 - 1.0V
84 GSensor ground
(Heated oxygen sensor 2,
Engine coolant temperature
sensor, Engine oil tempera-
ture sensor)[Engine is running]
Warm-up condition
Idle speed0V
PBIB3545E
Page 317 of 720
DTC P0139, P0159 HO2S2
EC-317
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Revision: 2006 November2007 350Z
BANK 2
TBWT1635E
Page 318 of 720

EC-318
DTC P0139, P0159 HO2S2
Revision: 2006 November2007 350Z
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
33 PU/WHeated oxygen sensor 2
heater (bank 2)[Engine is running]
Engine speed: Below 3,600 rpm 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 load.0 - 14V
[Ignition switch: ON]
Engine stopped
[Engine is running]
Engine speed: Above 3,600 rpmBATTERY VOLTAGE
(11 - 14V)
80 R/YHeated oxygen sensor 2
(bank 2)[Engine is running]
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 load.0 - 1.0V
84 GSensor ground
(Heated oxygen sensor 2,
Engine coolant temperature
sensor, Engine oil tempera-
ture sensor)[Engine is running]
Warm-up condition
Idle speed0V
PBIB3545E
Page 320 of 720

EC-320
DTC P0139, P0159 HO2S2
Revision: 2006 November2007 350Z
2. CLEAR THE SELF-LEARNING DATA
With CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CONSULT-III.
3. Clear the self-learning control coefficient by touching “CLEAR”.
4. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Without CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
3. Disconnect mass air flow sensor (bank 1) harness connector, and restart and run engine for at least 5 sec-
onds at idle speed.
4. Stop engine and reconnect mass air flow sensor (bank 1) harness connector.
5. Make sure DTC P0102 is displayed.
6. Erase the DTC memory. Refer to EC-61, "
HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFOR-
MATION" .
7. Make sure DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to EC-324, "DTC
P0171, P0174 FUEL INJECTION SYSTEM FUNCTION" or EC-334, "DTC P0172, P0175 FUEL
INJECTION SYSTEM FUNCTION" .
No >> GO TO 3.
1. Mass air flow sensor (with intake air
temperature sensor) (bank 1)2. Mass air flow sensor (with intake air
temperature sensor) (bank 2)
PBIB3501E