P0133

DTC PO133
FRONT OXYGEN SENSOR CIRCUIT SLOW RESPONSE (F02 - R)

Description
- The oxygen sensor is used to sense oxygen concentration in the exhaust gas. If the fuel ratio is leaner than the stoichiometric ratio in the mixture (i.e. excessive amount of air), the exhaust gas contains more oxygen. To the contrary, if the fuel ratio is richer than the stoichiometric ratio, the exhaust gas contains hardly any oxygen.
- Therefore, examination of the oxygen concentration in exhaust gas makes it possible to show whether the air/fuel ratio is leaner or richer than the stoichiometric ratio.
- The oxygen sensor has a zirconia tube (ceramic) which generates voltage if there is a difference in oxygen concentration between the inside and outside of the tube. Platinum is coated on the inside and outside of the zirconia tube for the purpose of catalysis and electrode provision. The hexagon screw on the outside is grounded to the exhaust pipe, and the inside is connected to the Engine Control Module (ECM) through the harness.
- A ceramic heater is employed to improve performance at low temperature.
- When rich air-fuel mixture is burnt in the cylinder, the oxygen in the exhaust gases reacts almost completely through the catalytic action of the platinum coating on the surface of the zirconia tube. This result is a very large difference in the oxygen concentration between the inside and outside, and the electromotive force generated is large.
- When a lean air-fuel mixture is burnt in the cylinder, oxygen remains in the exhaust gases even after the catalytic action, and this results in a small difference in the oxygen concentration. The electromotive force is very small.
- The difference in oxygen concentration changes greatly in the vicinity of the optimum air-fuel ratio and hence the change in the electromotive force is also large. By inputting this information into the Multiport Fuel Injected (MFI) Control Module the air/fuel ratio of the supplied mixture can be determined easily. The oxygen sensor does not generate much electromotive force when the temperature is low. The characteristics of the electromotive force stabilize at temperature of approximately 300 to 400°C (572 to 752°F).

DTC Detecting Condition
Two consecutive trips with fault.











1. Check DTC P0130 on display.

2. Check Exhaust System.
[CHECK]: Check the following.
- Looseness of installation portion of Front Exhaust Pipe onto Cylinder Heads
- Loosened connection of Front Exhaust Pipe and Front Catalytic Converter
- For damage of Exhaust Pipe which makes a hole.
[YES]: Repair exhaust system.
[NO]: Replace front Oxygen Sensor.