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. 2 of the right bank heated oxygen sensor (rear) is grounded with ECM
- The ECM
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 reach 0.2 volt after fuel cut operation.
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)
- Mass 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 degrees C (169 degrees F).
- The right bank heated oxygen sensor (front) is active.
- The cumulative mass airflow sensor output is higher than 1638 g.
- Fuel is being shut off.
Judgement Criterion
- Right bank oxygen sensor (rear) output voltage does not reach 0.2 volt for 6 seconds from fuel cut start.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 11. 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.
- Connector damage.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Replace the right bank heated oxygen sensor (rear).
1. Replace the right bank heated oxygen sensor (rear).
2. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 11. OBD-II Drive Cycle Pattern Lists
3. Check the diagnostic trouble code (DTC).
Q: Is DTC P0139 set?
YES: Refer to, P0137 - Heated Oxygen Sensor Circuit Low Voltage (bank 1, sensor 2), DTC P0138 - Heated Oxygen Sensor Circuit High Voltage (bank 1, sensor 2).
NO: The inspection is complete.