P0133
DTC P0133: Heated Oxygen Sensor Circuit Slow Response (sensor 1)Heated Oxygen Sensor (front) Circuit Part 1:
Heated Oxygen Sensor (front) Circuit Part 2:
CIRCUIT OPERATION
- A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the ECM (terminal No. 76)
- Terminal No. 2 of the heated oxygen sensor (front) is grounded with ECM (terminal No. 92)
TECHNICAL DESCRIPTION
- The heated oxygen sensor (front) detects the concentration of oxygen in the exhaust gas; it converts those data to voltage, and inputs the resulting signals to the ECM
- When the heated oxygen sensor (front) begins to deteriorate, the heated oxygen sensor signal response becomes poor.
- The ECM
DESCRIPTIONS OF MONITOR METHODS
- If the inversion frequency is low while monitoring the lean/rich inversion frequency of the heated oxygen sensor (front), the heated oxygen sensor (front) is determined to have deteriorated.
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 (front) heater monitor
- Misfire monitor
- Fuel system monitor
Sensor (The sensor below is determined to be normal)
- Manifold absolute pressure sensor
- Intake air temperature sensor
- Engine coolant temperature sensor
- Throttle position sensor
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flowchart
Check Conditions
- Engine coolant temperature is higher than 50 °C (122 °F).
- Engine speed is at between 1,200 and 3,000 r/min.
- Volumetric efficiency is at between 20 and 60 percent.
- Under the closed loop air/fuel control.
- Short-term fuel trim is at between -25 percent and +25 percent.
- The throttle valve is open.
- More than 2 seconds have elapsed after the mentioned conditions have been met.
- The ECM
Judgment Criteria
- The heated oxygen sensor (front) sends "lean" and "rich" signals alternately 10 times or less for 10 seconds.
NOTE: If the sensor switching frequency is lower than the Judgment Criteria due to the MUT-III OBD-II test Mode - HO2S Test Results, it is assumed that the heated oxygen sensor has deteriorated. If it is higher, it is assumed that the harness is damaged or has a short circuit.
If the heated oxygen sensor signal voltage has not changed even once (lean/rich) after the DTC was erased, the sensor switch time will display as 0 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Heated oxygen sensor (front) deteriorated.
- 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
STEP 1. Using scan tool MB991958, check data list item 11: Heated Oxygen Sensor (front).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool or 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 11, Heated Oxygen Sensor (front).
4. Warm up the engine, 2,500 r/min.
- Output voltage repeats 0.4 volt or less and 0.6 - 1.0 volt 10 times or more within 10 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 heated oxygen sensor (front). 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 Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0133 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.