P0133
DTC P0133: Heated Oxygen Sensor Circuit Slow Response (bank 1, sensor 1)
CIRCUIT OPERATION
- A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the ECM (terminal No. 54) from the output terminal (terminal No. 4) of the right bank heated oxygen sensor (front).
- Terminal No. 2 of the right bank heated oxygen sensor (front) is grounded with ECM
(terminal No. 55).
- The ECM applies an off set voltage of 0.5 volt to terminal No. 2 of the right bank oxygen sensor (front).
TECHNICAL DESCRIPTION
- The right bank 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 right bank heated oxygen sensor (front) begins to deteriorate, the heated oxygen sensor signal response becomes poor.
- The ECM also checks for the right bank heated oxygen sensor (front) rich learn switching frequency.
DESCRIPTIONS OF MONITOR METHODS
Right bank heated oxygen sensor (front) rich/lean switching frequency is under specified value.
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)
- Engine coolant temperature sensor
- Mass airflow sensor
- Intake air temperature sensor
- Barometric pressure sensor
- Throttle position sensor
- Accelerator pedal position sensor
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
- Engine coolant temperature is higher than 60°C (140°F).
- Engine speed is between 1,188 and 3,000 r/min.
- Volumetric efficiency is between 21 and 69 percent.
- Under the closed loop air/fuel control.
- The accelerator pedal is depressed.
- Short-term fuel trim is between -25 and +25 percent.
- More than 2 seconds have elapsed after the above mentioned conditions have been met.
- During the drive cycle, the ECM performs monitoring with the accumulated total time of 12 seconds, 5 times.
Judgement Criteria
- The average of the right bank heated oxygen sensor (front) rich/lean switching frequency is less than 11 times [Except for California] or 12 times [California] for the accumulated time of 12 seconds.
- The right bank heated oxygen sensor (front) rich/lean switching frequency is less than 20 times for the accumulated time of 12 seconds.
NOTE:
If the sensor switching frequency is lower than the Judgment Criteria due to the M.U.T.-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 second.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 Monitors, Trips, Drive Cycles and Readiness Codes.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
- Right bank heated oxygen sensor (front) deteriorated.
- ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991316: Test Harness
STEP 1. Check the right bank heated oxygen sensor (front)
(1)Disconnect the right bank heated oxygen sensor (front) connector B-03 and connect test harness special tool, MB991316, to the connector on the right bank heated oxygen sensor
(front) side.
(2)Warm up the engine until engine coolant temperature reaches 80°C (176°F) or higher.
(3)Rev the engine for 5 minutes or more with the engine speed of 4,500 r/min.
(4)Connect a digital voltage meter between terminal No. 2 (black clip) and terminal No. 4
(white clip).
(5)Warn up the engine, 2,500 r/min.
- Output voltage repeats 0 - 0.4 volt or less and 0.6 - 1.0 volts 13 times or more within 12 seconds.
CAUTION:
- Be very careful when connecting the jumper wires; incorrect connection can damage the heated oxygen sensor
- Be careful the heater can be damaged if a voltage beyond 8 volts is applied to the heated oxygen sensor heater.
NOTE:
If the temperature of sensing area does not reach the high temperature [of approximately 400°C (752°F) or more] even though the oxygen sensor is normal, the output voltage would be possibly low in spite of the rich air-fuel ratio. Therefore, if the output voltage is low, use a jumper wire to connect the terminal No.1 (red clip) and the terminal No. 3 (blue clip) of the heated oxygen sensor with the positive terminal and the negative terminal of 8 volts power supply respectively, then check again.
Q. Is the sensor operating properly?
YES Go to Step 2.
NO Replace the right bank 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 - Pattern 1 Monitors, Trips, Drive Cycles and Readiness Codes.
(2)Check the diagnostic trouble code (DTC).
Q. Is DTC P0133 set?
YES Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID registration procedure manual - ID codes registration judgement table [Vehicles with KOS] or ID registration procedure manual - ID codes registration judgement table [Vehicles with WCM].
NO It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.