2009 NISSAN LATIO service

DTC P0139 HO2S2
EC-1251
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DTC P0139 HO2S2
Component Description INFOID:0000000004501151
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 c ontrolled 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 Val ue in Data Monitor Mode INFOID:0000000004501152
Specification data are reference values.
On Board Diagnosis Logic INFOID:0000000004500103
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 Procedure INFOID:0000000004500104
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
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 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 - 0.3V
←→ Approx. 0.6 - 1.0V
HO2S2 MNTR (B1) LEAN ←→ RICH SEF302U
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0139
0139 Heated oxygen sensor 2
circuit slow response It 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

EC-1252< SERVICE INFOMATION >
[MR TYPE 2]
DTC P0139 HO2S2
1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.
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 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 “C OOLAN TEMP/S” indication reaches to 70°C (158 °F).
7. Select “HO2S2 (B1) P0139” of “HO2S2” in “DTC WORK SUPPORT” mode with CONSULT-III.
8. Following the instruction of CONSULT-III. NOTE:
It will take at most 10 minutes until “COMPLETED” is displayed.
9. Make sure that “OK” is display ed after touching “SELF-DIAG RESULTS”.
If “NG” is displayed, refer to EC-1254, " Diagnosis Procedure " .
If “CAN NOT BE DIAG NOSED” is displayed, perform the following.
a. Turn ignition switch OFF and leave the vehi cle in a cool place (soak the vehicle).
b. Return to step 1.
Overall Function Check INFOID:0000000004500105
Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st
trip DTC might not be confirmed.
WITH GST
1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Start engine and keep the engine between 3,500 and 4,000 rpm for at least 1 minute under no load.
4. Let engine idle for 1 minute.
5. Set voltmeter probes between ECM terminal 50 (HO2S2 signal) and ground.
6. Check the voltage when revving up to 4,000 rpm under no load
at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
A change of voltage should be more than 0.8V for 1 second
during this procedure.
If the voltage can be confirmed in step 6, step 7 is not nec-
essary.
7. Keep vehicle at idling for 10 minutes, then check the voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in D
position with OD OFF (A/T), D position (CVT) or 3rd gear posi-
tion (M/T).
A change of voltage should be more than 0.8V for 1 second
during this procedure.
8. If NG, go to EC-1254, " Diagnosis Procedure " . PBIB2996E

DTC P0139 HO2S2
EC-1253
< SERVICE INFOMATION >
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Wiring Diagram
INFOID:0000000004501154
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-III.
CAUTION: BBWA2629E

EC-1254< SERVICE INFOMATION >
[MR TYPE 2]
DTC P0139 HO2S2
Do not use ECM ground terminals when measuring in put/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis Procedure INFOID:00000000045001071.
CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screw on the body. Refer to EC-1144, " Ground Inspection " .
OK or NG OK >> GO TO 2.
NG >> Repair or replace ground connections. 2.
CLEAR THE SELF-LEARNING DATA
With CONSULT-III
TERMI-
NAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
5 G Heated oxygen sensor 2
heater [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. Approximately 10V
[Ignition switch: ON]
• Engine stopped
[Engine is running]
• Engine speed: Above 3,600 rpm. BATTERY VOLTAGE
(11 - 14V)
50 W Heated oxygen sensor 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 - Approximately 1.0V
59 O Sensor ground
(Heated oxygen sensor 2) [Engine is running]
• Warm-up condition
• Idle speed Approximately 0V PBIA8148J
:
Vehicle front
1. Body ground E24 2. Engine ground F9 3. Engine ground F16
4. Body ground E15 BBIA0698E

DTC P0139 HO2S2
EC-1255
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1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “W ORK 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 or P0172 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 (1) harness connector, and
restart and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness con- nector.
5. Make sure that DTC P0102 is displayed.
6. Erase the DTC memory. Refer to EC-1052, " Emission-related
Diagnostic Information " .
7. Make sure that DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171 or P0172 detected?
Is it difficult to start engine?
Yes or No Yes >> Perform trouble diagnosis for DTC P0171 or P0172. Refer to
EC-1258 or
EC-1264 .
No >> GO TO 3. 3.
CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 2 harness connector (2).
- : Vehicle front
- Heated oxygen sensor 2 (1)
3. Disconnect ECM harness connector.
4. Check harness continuity between HO2S2 terminal 1 and ECM
terminal 59. 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 HO2S2 terminal 4 and ECM terminal 50. Refer to Wiring Diagram.
2. Check harness continuity between ECM terminal 50 or HO2S2 terminal 4 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. 5.
CHECK HEATED OXYGEN SENSOR 2
Refer to EC-1256, " Component Inspection " .
OK or NG BBIA0701E
Continuity should exist.
BBIA0700E
Continuity should exist.
Continuity should not exist.

EC-1256< SERVICE INFOMATION >
[MR TYPE 2]
DTC P0139 HO2S2
OK >> GO TO 6.
NG >> Replace heated oxygen sensor 2. 6.
CHECK INTERMITTENT INCIDENT
Refer to EC-1138 .
>> INSPECTION END
Component Inspection INFOID:0000000004501156
HEATED OXYGEN SENSOR 2 With CONSULT-III
1. Start engine and warm it up to the 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 1 minute under no load.
4. Let engine idle for 1 minute.
5. Select “FUEL INJECTION” in “ACT IVE TEST” mode, and select “HO2S2 (B1)” as the monitor item with
CONSULT-III.
6. Check “HO2S2 (B1)” at idle speed when adjusting “FUEL INJECTION” to ±25%.
“HO2S2 (B1)” should be above 0.68V at least once when the “FUEL INJECTION” is +25%.
“HO2S2 (B1)” should be below 0.18V at least once when the “FUEL INJECTION” is −25%.
CAUTION:
• Discard any heated oxygen senso r which has been dropped from a height of more than 0.5 m
(19.7 in) onto a hard surface such as a concrete floor; use a new one.
• Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor
Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Without CONSULT-III
1. Start engine and warm it up to the 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 1 minute under no load.
4. Let engine idle for 1 minute.
5. Set voltmeter probes between ECM terminal 50 (HO2S2 signal) and ground.
6. Check the voltage when revving up to 4,000 rpm under no load at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
The voltage should be above 0.68V and below 0.18V at least
once during this procedure.
If the voltage can be confirmed at step 6, step 7 is not nec-
essary.
7. Keep vehicle idling for 10 minutes, then check voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in D position
with OD OFF (A/T), D position (CVT) or 3rd gear position (M/T).
The voltage should be above 0.68 and below 0.18V at least
once during this procedure.
8. If NG, replace heated oxygen sensor 2. PBIB3458E
PBIB2996E

DTC P0171 FUEL INJECT
ION SYSTEM FUNCTION
EC-1259
< SERVICE INFOMATION >
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CAUTION:
Always drive vehicle at a safe speed.
d. Check 1st trip DTC.
e. If 1st trip DTC is detected, go to EC-1261, " Diagnosis Procedure " .
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Disconnect mass air flow sensor (1) harness connector.
4. Restart engine and let idle for at least 5 seconds.
5. Stop engine and reconnect mass air flow sensor (1) harness connector.
6. Select Service $03 with GST. Make sure DTC P0102 is detected.
7. Select Service $04 with GST and erase the DTC P0102.
8. Start engine. If it is difficult to start engine, the fuel injection system has a mal-
function.
Perform the following procedure is advised.
a. Crank engine while depressing accelerator pedal. NOTE:
When depressing accelerator pedal three-fourths (3/4) or more, the control system does not start the
engine. Do not depress accelerator pedal too much.
b. If engine starts, go to EC-1261, " Diagnosis Procedure " .
If engine does not start, check exhaust and intake air leak visually.
9. Keep engine at idle for at least 5 minutes.
10. Check 1st trip DTC. The 1st trip DTC P0171 should be det ected at this stage, if a malfunction exists. If so, go to EC-1261," Diagnosis Procedure " .
NOTE:
If 1st trip DTC is not detected during above proc edure, performing the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine.
c. Maintain the following conditions for at least 10 consecutive minutes. Hold the accelerator pedal as steady as possible.
CAUTION:
Always drive vehicle at a safe speed.
d. Check 1st trip DTC.
e. If 1st trip DTC is detected, go to EC-1261, " Diagnosis Procedure " .
VHCL SPEED SE 50 – 120 km/h (31 – 75 MPH)
VHCL SPEED SE 50 – 120 km/h (31 – 75 MPH) BBIA0701E

DTC P0171 FUEL INJECT
ION SYSTEM FUNCTION
EC-1261
< SERVICE INFOMATION >
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Do not use ECM ground terminals wh
en measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis Procedure INFOID:00000000045001131.
CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).
OK or NG OK >> GO TO 2.
NG >> Repair or replace. 2.
CHECK FOR INTAKE AIR LEAK AND PCV HOSE
TERMI-
NAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
3 G A/F sensor 1 heater [Engine is running]
• Warm-up condition
• Idle speed (More than 140 seconds after starting engine) Approximately 2.9 - 8.8V
25
29
30
31 V
Y
O
L Fuel injector No. 4
Fuel injector No. 3
Fuel injector No. 2
Fuel injector No. 1 [Engine is running]
• Warm-up condition
• Idle speed NOTE:
The pulse cycle changes depending on rpm at
idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
• Warm-up condition
• Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
49 W A/F sensor 1 [Engine is running]
• Warm-up condition
• Engine speed: 2,000 rpm Approximately 1.8V
Output voltage varies with air
fuel ratio.
53 B A/F sensor 1 [Ignition switch: ON] Approximately 2.2V PBIA8148J
PBIB0529E
PBIA4943J
PBIB1216E