P0139
P0139, P0159 HO2S2
Component Description
The heated oxygen sensor 2, after three way catalyst (manifold), 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 signal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1 V in richer conditions to 0 V in leaner conditions.
Under normal conditions the heated oxygen sensor 2 is not used for engine control operation.
On Board Diagnosis Logic
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 oxygen storage capacity of 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 sensor's voltage is faster than specified during various driving conditions such as fuel cut.
DTC Confirmation Procedure
1. INSPECTION START
Do you have SDT?
Do you have SDT?
YES
GO TO 2.
NO
GO TO 7.
2. PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
1 Turn ignition switch OFF and wait at least 10 seconds.
2 Turn ignition switch ON.
3 Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
For better results, perform "DTC work support" at a temperature of 0 to 30 °C (32 to 86 °F).
GO TO 3.
3. PERFORM DTC CONFIRMATION PROCEDURE
With SDT
1 Turn ignition switch ON and select "Data list" mode with SDT.
2 Start engine and warm it up to the normal operating temperature.
3 Turn ignition switch OFF and wait at least 10 seconds.
4 Turn ignition switch ON.
5 Turn ignition switch OFF and wait at least 10 seconds.
6 Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
7 Let engine idle for 1 minute.
8 Make sure that "COOLAN TEMP/S" indicates more than 70 °C (158 °F).
9 Drive the vehicle at a speed of 60 km/h (38 MPH) on the suitable gear position and keep the speed.
CAUTION:
Always drive vehicle at a safe speed.
10 Release the accelerator pedal fully at least 5 seconds.
CAUTION:
- Make it the condition that engine brake operates.
- Always drive vehicle safely.
- Never apply brake when releasing the accelerator pedal.
11 Repeat step 9 and 10 at least 8 times.
12 Check the following item of "Data list".
Is "CMPLT" displayed on SDT screen?
YES
GO TO 6.
NO-1: "CMPLT" are not displayed on DIAG 1
Perform DTC confirmation procedure again.
NO-2: "CMPLT" are not displayed on DIAG 2
ERROR! Unknown action!GO TO 4.
4. PERFORM DTC WORK SUPPORT
1 Open engine hood.
2 Select "HO2S2 (B1) P0139" or "HO2S2 (B2) P0159" of "HO2S2" in "DTC work support" mode with SDT.
3 Start engine and follow the instruction of SDT display.
NOTE:
It will take at most 10 minutes until "COMPLETED" is displayed.
Is "COMPLETED" displayed on SDT screen?
YES
GO TO 6.
NO
GO TO 5.
5. PERFORM DTC CONFIRMATION PROCEDURE AGAIN
1 Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).
2 Perform DTC confirmation procedure again.
GO TO 3.
6. PERFORM DTC CHECK
With SDT
Perform ECM DTC check.
Is DTC "P0139" or "P0159" detected?
YES
Proceed to "Diagnosis Procedure".
NO
INSPECTION END
7. PERFORM COMPONENT FUNCTION CHECK
Perform component function check. Refer to "Overall Function Check".
NOTE:
Use component function check to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st trip DTC might not be confirmed.
Is the inspection result normal?
YES
INSPECTION END
NO
Proceed to "Diagnosis Procedure".
Overall Function Check
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) Turn ignition switch ON.
4) Turn ignition switch OFF and wait at least 10 seconds.
5) Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
6) Let engine idle for 1 minute.
7) Set voltmeter probes between ECM terminal 74 [HO2S2 (B1) signal] or 55 [HO2S2 (B2) signal] and ground.
8) 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 0.8 V for 1 second during this procedure.
If the voltage can be confirmed in step 6, step 7 is not necessary.
9) 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), 5th gear position (M/T).
A change of voltage should be more than 0.8 V for 1 second during this procedure.
10) If NG, go to "Diagnosis Procedure".
Diagnosis Procedure
1. CHECK GROUND CONNECTIONS
1 Turn ignition switch OFF.
2 Loosen and retighten three ground screws on the body. Refer to [Power Supply and Ground Circuit Check] Power Supply and Ground Circuit Check.
OK or NG
OK
GO TO 2.
NG
Repair or replace ground connections.
2. CLEAR THE SELF-LEARNING DATA
With SDT
1 Start engine and warm it up to normal operating temperature.
2 Select "SELF-LEARNING CONT" in "Utility" mode with SDT.
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 SDT
1 Start engine and warm it up to normal operating temperature.
2 Turn ignition switch OFF.
3 Disconnect mass air flow sensor 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 connector.
5 Check DTC P0102 is displayed.
6 Erase the DTC memory. Refer to [On Board Diagnosis Function] On Board Diagnosis Function (Without SDT) or [SDT Function] SDT Function (With SDT).
7 Check 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?
Yes or No
Yes
Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to [P0171, P0174 Fuel Injection System Function] P0171 or [P0172, P0175 Fuel Injection System Function] P0172.
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.
3 Disconnect ECM harness connector.
4 Check harness continuity between HO2S2 terminal 4 and ECM terminal 78.
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.
5. CHECK HEATED OXYGEN SENSOR 2
Refer to "Component Inspection".
OK or NG
OK
GO TO 6.
NG
Replace malfunctioning heated oxygen sensor 2. Refer to [Exhaust System: Exploded View] Exploded View.
6. CHECK INTERMITTENT INCIDENT
Refer to [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.
INSPECTION END
Component Inspection
Heated Oxygen Sensor 2
With SDT
1) Turn ignition switch ON and select "Data list" mode with SDT.
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) Select "FUEL INJECTION" in "Active test" mode, and select "HO2S2 (B1)/(B2)" as the monitor item with SDT.
7) Check "HO2S2 (B1)/(B2)" at idle speed when adjusting "FUEL INJECTION" to ±25%.
"HO2S2 (B1)/(B2)" should be above 0.68 V at least once when the "FUEL INJECTION" is +25%.
"HO2S2 (B1)/(B2)" should be below 0.18 V at least once when the "FUEL INJECTION" is -25%.
CAUTION:
- Discard any heated oxygen sensor 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 SDT
8) Start engine and warm it up to the normal operating temperature.
9) Turn ignition switch OFF and wait at least 10 seconds.
10) Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
11) Let engine idle for 1 minute.
12) Set voltmeter probes between ECM terminal 74 [HO2S2 (B1) signal] or 55 [HO2S2 (B2) signal] and ground.
13) 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 0.68 V at least once during this procedure.
If the voltage is above 0.68 V at step 6, step 7 is not necessary.
14) Keep vehicle at 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), 5th gear position (M/T).
The voltage should be below 0.18 V at least once during this procedure.
15) If NG, replace heated oxygen sensor 2. Refer to [Exhaust System: Exploded View] Exploded View.
CAUTION:
- Discard any heated oxygen sensor 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.