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Troubleshooting

P0133 - H2OS Circuit Slow Responce (Bank 1 Sensor 1)

CIRCUIT DESCRIPTION




DTC Detection Condition:




To obtain a high purification rate of the CO, HC and NOx components of the exhaust gas, a three-way catalytic converter is used. 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 oxygen sensor has the characteristic whereby its output voltage changes suddenly in the vicinity of the stoichiometric air-fuel ratio. This characteristic is used to detect the oxygen concentration in the exhaust gas and provide the ECM with feedback to control the air-fuel ratio.

When the air-fuel ratio becomes LEAN, the oxygen concentration in the exhaust gas increases and the oxygen sensor informs the ECM of the LEAN condition (small electromotive force: <0.45 V).

When the air-fuel ratio is RICHER than the stoichiometric air-fuel ratio, the oxygen concentration in the exhaust gas is reduced and the oxygen sensor informs the ECM of the RICH condition (large electromotive force: >0.45 V). The ECM judges by the electromotive force from the oxygen sensor whether the air-fuel ratio is RICH or LEAN and controls the injection time accordingly. However, if a malfunction of the oxygen sensor causes an output of abnormal electromotive force, the ECM is unable to perform accurate air-fuel ratio control. The heated oxygen sensors include a heater which heats the zirconia element. The heater is controlled by the ECM. When the intake air volume is low (temperature of the exhaust gas is low), current flows to the heater to heat the sensor for accurate oxygen concentration detection.

HINT:
- Bank 1 refers to the bank that includes cylinder No.1.
- Bank 2 refers to the bank that does not include cylinder No.1.
- Sensor 1 refers to the sensor being closer to the engine body.

Wiring Diagram:






CONFIRMATION DRIVING PATTERN

Confirmation Driving Pattern:




1. Connect the hand-held tester to the DLC3.
2. Switch the hand-held tester from the normal mode to the check (test) mode.
3. Start the engine and let the engine idle for 100 seconds or more.
4. Drive the vehicle at 40 km/h (24 mph) or more for 20 seconds or more.
5. Let the engine idle for 20 seconds or more.
6. Let the engine idle for 30 seconds.

HINT: If a malfunction exists, the MIL will light up during step (6).

NOTE: If the conditions in this test are not strictly followed, detection of the malfunction will be impossible.
If you do not have a TOYOTA hand-held tester, turn the ignition switch OFF after performing steps (3) to (6) once, then perform steps (3) to (6) again.

Step 1:




Steps 2 - 4:




Steps 5 - 8:




INSPECTION PROCEDURE

HINT: Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool, as freeze frame data records the engine conditions when a 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 the 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 DTCs.
2. Set the check mode.
3. Perform a simulation test.
4. Check the connector and terminal.
5. Handle the connector.