Code No. P0133: Oxygen Sensor (front) Circuit Slow Response <M/T>

The sensor signal is inputted to the engine-ECU (terminal No. 38) from the oxygen sensor (front) output terminal (terminal No. 3).
The oxygen sensor (front) (terminal No. 4) is earthed with engine-ECU (terminal No. 39).

The oxygen sensor (front) converts the concentration of oxygen in the exhaust emission into a voltage and inputs the signal to the engine-ECU.
When the air-fuel ratio is richer than the theoretical air-fuel ratio, the oxygen sensor (front) outputs a voltage of about 1 V. When it is leaner than the theoretical air-fuel ratio, it outputs a voltage of about 0 V.
In response to the signal, the engine-ECU controls the fuel injection amount so that the air-fuel ratio can be equivalent to the theoretical air-fuel ratio.

Check Conditions

Engine coolant temperature is more than 50°C.
Engine speed is more than 1,500 r/min and is less than 3,000 r/min.
Inlet manifold pipe pressure is more than 27 kPa and is less than 60 kPa.
Under the closed loop air/fuel control.
The accelerator pedal is open.
Short-term fuel trim is more than -25 % and is less than +25 %.
More than 2 seconds have elapsed after the above mentioned conditions have been met.

Judgement Criterion

The average of the oxygen sensor (front) rich/lean switching frequency is less than 10 times per 10 seconds.
The engine-ECU monitors for this condition for 7 cycles of 10 seconds each during the drive cycle.

DIAGNOSIS PROCEDURE

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Go to Step 2 .

	Go to Step 3 .

	Replace the oxygen sensor (front).

	Go to Step 4 .

	Repair or replace the connector.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Replace the engine-ECU.