Except Vehicles For California

DTC P0133: Linear Air-Fuel Ratio Sensor Circuit Slow Response [Except vehicles for California]










TECHNICAL DESCRIPTION

- The ECM effects air/fuel ratio feedback control in accordance with the signals from the linear air-fuel ratio sensor.
- If the linear air-fuel ratio sensor has deteriorated, corrections will be made by the heated oxygen sensor (rear).

DESCRIPTIONS OF MONITOR METHODS

- If the response speed of the linear air-fuel ratio sensor to the change in the air-fuel ratio is too slow, the DTC is stored as the linear air-fuel ratio sensor deterioration.

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)

- Linear air-fuel ratio sensor heater monitor
- Misfire monitor
- Fuel system monitor
Sensor (The sensor below is determined to be normal)

- Mass airflow sensor
- Engine coolant temperature sensor
- Intake air temperature sensor
- Barometric pressure sensor
- Throttle position sensor
- Accelerator pedal position sensor

DTC SET CONDITIONS

Logic Flow Chart






Check Conditions

- Engine speed is between 1,500 and 3,500 r/min[M/T] or 1,219 and 3,000 r/min[CVT].
- Volumetric efficiency is between 22 and 65 percent[M/T] or 25 and 70 percent[CVT].
- Engine coolant temperature is more than 60°C (140°F).
- Under the closed loop air/fuel control.
- The accelerator pedal is depressed.
- Short-term fuel trim is between -25 and +25 percent.
- More than 3 seconds have passed after the above mentioned conditions have been met.
- During the drive cycle, the ECM performs monitoring with the accumulated total time of 10 seconds, 5 times.
Judgement Criteria

- The average frequency is less than 8 times.
- The frequency is less than 13 times.

FAIL-SAFE AND BACKUP FUNCTION

- None

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnosis 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:)

- Linear air-fuel ratio sensor failed.
- Connector damage.

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A

STEP 1. Check harness connector C-55 at linear air-fuel ratio sensor and harness connector B-108 at ECM for damage.

Q. Is the harness connector in good condition?

YES Go to Step 2.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 3.
STEP 2. Test the OBD-II drive cycle.





CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

(1)Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to the "ON" position and delete the DTC.
(3)Carry out the test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 Monitors, Trips, Drive Cycles and Readiness Codes.
(4)Check the diagnostic trouble code (DTC).

Q. Is DTC P0133 set?

YES Replace the linear air-fuel ratio sensor. Then go to Step 3.

NO It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.

STEP 3. 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 Retry the troubleshooting.
NO The inspection is complete.