P0139
Right Bank Heated Oxygen Sensor (rear) Circuit:
Connectors:
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 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
DTC SET CONDITIONS
Check Conditions
- Engine coolant temperature is higher than 76 °C (169 °F).
- The right bank heated oxygen sensor (front) is active.
- The cumulative volume air flow 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 rpm.
- Volumetric efficiency is higher than 40 percent.
- Vehicle speed is higher than 30km/h (18.7 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 (0.9 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.
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 Tool:
- MB991502: Scan Tool (MUT-II)
STEP 1. Using scan tool MB991502, check data list item 69: Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).
CAUTION
To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991502 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 INTRODUCTION, How to Use Troubleshooting/Inspection Service Points.
NO: Replace the right bank heated oxygen sensor (rear). Then go to Step 2.
STEP 2. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Trouble Code Diagnosis - OBD-II Drive Cycle - Procedure 4 - Heated Oxygen Sensor Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0139 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.