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DTC P0140-00: Heated oxygen sensor (rear) no activity detected
 
 
 
 
CIRCUIT OPERATION
  • The sensor signal is inputted to the ECM connector terminal number 49 from the heated oxygen sensor (rear) connector terminal number 4.
  • The heated oxygen sensor (rear) connector terminal number 3 is grounded with ECM connector terminal number 50.
  • The ECM connector terminal number 50 applies an offset voltage of 0.5 volt to the heated oxygen sensor (rear) connector terminal number 3.
 
 
TECHNICAL DESCRIPTION
  • The output signal of the linear air-fuel ratio sensor is compensated by the output signal of the heated oxygen sensor (rear).
  • The ECM checks for the heated oxygen sensor (rear) output voltage.
 
 
DESCRIPTIONS OF MONITOR METHODS
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 set in memory for the item monitored below)
  • Linear air-fuel ratio sensor monitor
  • Linear air-fuel ratio sensor heater monitor
  • Heated oxygen sensor (rear) heater monitor
  • Heated oxygen sensor offset voltage monitor
Sensor (The sensor below is determined to be normal)
  • Mass airflow sensor
  • Engine coolant temperature sensor
  • Intake air temperature sensor
  • Barometric pressure sensor
  • Fuel tank pressure sensor
 
 
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
  • Engine coolant temperature is higher than 76°C (169°F).
  • The linear air-fuel ratio sensor is active.
  • 5 seconds or more have passed since the estimated catalytic converter temperature is higher than 600°C (1,112°F).
  • Repeat one time or more: 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 30 km/h (19 mph) or higher.
      • Sum of time accumulated higher than 60 seconds.
    • Stop*2:
      • Vehicle speed is lower than 1.5 km/h (1 mph).
        or
      • Engine speed is lower than 1,000 r/min.
  • Time of continuous fuel-cut during each Go/Stop operation is longer than 3 seconds.
Judgment Criterion
  • Change in the output voltage of the heated oxygen sensor (rear) is lower than 0.313 volt.
    or
  • The maximum output voltage of the heated oxygen sensor (rear) is 0.508 volt or lower.
noteMonitoring stops when the estimated catalytic converter temperature is 500°C (932°F) or lower.
 
 
FAIL-SAFE AND BACKUP FUNCTION
None.
 
 
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 5 OBD- II DRIVE CYCLE.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
  • Heated oxygen sensor (rear) deteriorated.
  • Connector damage.
  • ECM failed.
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
1.STEP 1. Using scan tool (M.U.T.-III SE), check the data list.
Use scan tool (M.U.T.-III SE) to check the data list (Refer to DATA LIST REFERENCE TABLE).
  • Item number A1501: Oxygen sensor(bank1 sensor2)
Q: Is the check result normal?
Replace the heated oxygen sensor (rear) (Refer to ENGINE, Engine, Motor and Emission Control – Emission Control – Exhaust Gas Purification System CATALYTIC CONVERTER REMOVAL AND INSTALLATION). Then
 
2.STEP 2. Test the OBD-II drive cycle.
After erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Use scan tool (M.U.T.-III SE) to erase the DTC.
(2) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 5 OBD- II DRIVE CYCLE).
(3) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC P0140-00 set?
Replace the ECM (Refer to ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION).
Intermittent malfunction (Refer to GENERAL INFORMATION, General Information – How to Use Troubleshooting/Inspection Service Points – How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).
 
3.STEP 3. Test the OBD-II drive cycle.
After erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Use scan tool (M.U.T.-III SE) to erase the DTC.
(2) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 5 OBD- II DRIVE CYCLE).
(3) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC P0140-00 set?
Perform troubleshooting for the oxygen sensor (rear) system [Refer to diagnostic trouble code procedures for DTC P0137-00: Oxygen Sensor (rear) circuit low voltage DTC P0137-00: Oxygen Sensor (rear) circuit low voltage), and Refer to diagnostic trouble code procedure for DTC P0138-00: Oxygen Sensor (rear) circuit high voltage DTC P0138-00: Oxygen Sensor (rear) circuit high voltage)].
The inspection is complete.