P0139
DTC P0139: Heated Oxygen Sensor Circuit Slow Response (bank 1, sensor 2)Right Bank Heated Oxygen Sensor (rear) Circuit Part 1:
Right Bank Heated Oxygen Sensor (rear) Circuit Part 2:
CIRCUIT OPERATION
- A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the ECM (terminal No. 74)
- Terminal No. 2 of the right bank heated oxygen sensor (rear) is grounded with ECM (terminal No. 49)
TECHNICAL DESCRIPTION
- The output signal of the right bank heated oxygen sensor (front) is compensated by the output signal of the right bank heated oxygen sensor (rear).
- The ECM
DESCRIPTIONS OF MONITOR METHODS
Right bank heated oxygen sensor (rear) output voltage does not change during specified go/stop operations including fuel cut are repeated.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Heated oxygen sensor heater (front) monitor
- Heated oxygen sensor heater (rear) monitor
- Air/fuel ratio feedback monitor
Sensor (The sensor below is determined to be normal)
- Volume airflow sensor
- Engine coolant temperature sensor
- Intake air temperature sensor
- Barometric pressure sensor
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- Engine coolant temperature is higher than 76 °C (169 °F).
- The right bank heated oxygen sensor (front) is active.
- The cumulative volume airflow sensor output frequency is higher than 4,000 Hz.
- Repeat 3 or more times: drive*1, stop*2.
Drive*1:
- Engine speed is higher than 1,500 r/min.
- Volumetric efficiency is higher than 40 percent.
- Vehicle speed is higher than 30 km/h (19 mph).
- A total of more than 10 seconds have elapsed with the above mentioned conditions, and more than 2 seconds have elapsed with the fuel shut off.
Stop*2:
- Vehicle speed is lower than 1.5 km/h (1.0 mph).
Judgement Criteria
- Change in the output voltage of the right bank heated oxygen sensor (rear) is lower than 0.312 volt.
NOTE: Monitoring stops after fuel has been shut off for more than 38 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to, Diagnostic Function - OBD-II Drive Cycle - Procedure 4 - Heated Oxygen Sensor Monitor. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Right bank heated oxygen sensor (rear) failed.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
- MB991316:Test Harness
STEP 1. Using scan tool MB991958, check data list item 69: Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991958 to the data reading mode for item 69, Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).
4. Warm up the engine.
- After increasing the output voltage 0.15 volt or more by the engine revving, finish it. Then confirm that the output voltage reduces to 0.15 volt or less within 3 seconds.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: It can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/ Inspection Service Points.
NO: Replace the right bank heated oxygen sensor (rear). Then go to Step 2.
STEP 2. Check the right bank heated oxygen sensor (rear).
1. Disconnect the right bank heated oxygen sensor (rear) connector B-28 and connect test harness special tool, MB991316, to the connector on the right bank heated oxygen sensor (rear) side.
2. Warm up the engine until engine coolant 80 °C (176 °F) or higher.
CAUTION: Be very careful when connecting the jumper wires; incorrect connection can damage the right bank heated oxygen sensor (rear).
3. Use the jumper wires to connect terminal No. 1 (red clip) to the positive battery terminal and terminal No. 3 (blue clip) to the negative battery terminal.
4. Connect a digital volt meter between terminal No. 2 (black clip) and terminal No. 4 (white clip).
5. While repeatedly revving the engine, measure the right bank heated oxygen sensor (rear) output voltage.
Standard value: 0.6 - 1.0 volt
Q: Is the voltage between 0.6 and 1.0 volt?
YES: Go to Step 3.
NO: Replace the right bank heated oxygen sensor (rear). Then go to Step 4.
STEP 3. Check harness connector B-28 at right bank heated oxygen sensor (rear) and harness connector C-58, C-62 at ECM or C-55, C-59 at PCM for damage.
Q: Is the harness connector in good condition?
YES: Replace the PCM.Then go to Step 4.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 4.
STEP 4. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 4 - Heated Oxygen Sensor Monitor. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0139 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.