P1133

CIRCUIT DESCRIPTION

DTC Detecting Condition:

To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three-way catalytic converter is used, but for the most efficient use of the three-way catalytic converter, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric air-fuel ratio.

The A/F sensor has the characteristic that provides output voltages approximately proportional to the existing air-fuel ratio. The A/F sensor output Voltage* is used to provide feedback for the ECM to control the air-fuel ratio.

By the A/F sensor output, the ECM can determine the deviation amount from the stoichiometric air-fuel ratio and control the proper injection time immediately. If the A/F sensor is malfunctioning, ECM is unable to perform accurate air-fuel ratio control.

The A/F sensor is equipped with a heater which heats the zirconia element. The heater is controlled by the ECM. When the intake air volume is low (the temperature. of the exhaust gas is low), current flows to the heater to heat the sensor for accurate oxygen concentration detection.

*: The voltage value changes at the inside of the ECM only

Step 1:

Step 2:

Steps 3 - 6:

Steps 7 - 10:

INSPECTION PROCEDURE

HINT: Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air-fuel ratio lean or rich, etc. at the time of the malfunction.

CHECK FOR INTERMITTENT PROBLEMS

TOYOTA HAND-HELD TESTER only:
By putting the vehicle's ECM in check mode, 1 trip detection logic is possible instead of 2 trip detection logic and sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.
1. Clear the DTC.
2. Set the check mode.
3. Perform a simulation test.
4. Check the connector and terminal.
5. Handle the connector.

CONFIRMATION DRIVING PATTERN




1. Connect the TOYOTA hand-held tester to the DLC3.
2. Switch the TOYOTA hand-held tester from normal mode to check mode.
3. Start the engine and warm it up with all accessory switches OFF.
4. Drive the vehicle at 60 - 120 km/h (38 - 75 mph) and engine speed at 1,600 - 3,200 rpm for 3 - 5 mm.

HINT: If a malfunction exists, the MIL will light up during step (4).

NOTE: If the conditions in this test are not strictly followed, detection of the malfunction will not be possible. If you do not have a TOYOTA hand-held tester, turn the ignition switch OFF after performing steps (3) and (4), then perform steps (3) and (4) again.