DTC P0133: Notes

DETECTION CONDITION AND POSSIBLE CAUSE (DTC P0133)

DTC P0133	Front HO2S circuit problem
DETECTION CONDITION	Front HO2S malfunction is detected by measuring of the average frequency of front HO2S signal, time required to pass from rich to lean, time required to pass from lean to rich. If the average frequency of front HO2S signal is more than the threshold value, the PCM determines that there is the front HO2S circuit problem. MONITORING CONDITIONS HO2S heater, HO2S, and TWC Repair Verification Drive Mode Following conditions are met: Engine speed is 1,750-3,500 rpm . Charging efficiency is 25-63% (at engine speed 2,500 rpm ). Engine coolant temperature is above 70°C {158°F} Front HO2S heater monitor is completed. Fuel system loop status is closed loop fuel control. Diagnostic support note This is an intermittent monitor. (HO2S) The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. DIAGNOSTIC MONITORING TEST RESULTS is available. PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle. FREEZE FRAME DATA is available. The DTC is stored in the PCM memory.
POSSIBLE CAUSE	Front HO2S deterioration Front HO2S malfunction Front HO2S looseness Pressure regulator (built-in fuel pump unit) malfunction Fuel pump malfunction Clogged or restricted fuel filter (built-in fuel pump unit) Fuel leakage in fuel line between fuel distribution pipe and fuel pump Exhaust system leakage Purge solenoid valve malfunction Improper connection purge solenoid hose Insufficient compression Engine malfunction (Engine coolant leakage)

DTC P0133

Front HO2S circuit problem

DETECTION CONDITION

Front HO2S malfunction is detected by measuring of the average frequency of front HO2S signal, time required to pass from rich to lean, time required to pass from lean to rich. If the average frequency of front HO2S signal is more than the threshold value, the PCM determines that there is the front HO2S circuit problem.

MONITORING CONDITIONS

HO2S heater, HO2S, and TWC Repair Verification Drive Mode
Following conditions are met:

Engine speed is 1,750-3,500 rpm .
Charging efficiency is 25-63% (at engine speed 2,500 rpm ).
Engine coolant temperature is above 70°C {158°F}
Front HO2S heater monitor is completed.
Fuel system loop status is closed loop fuel control.

Diagnostic support note

This is an intermittent monitor. (HO2S)
The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
DIAGNOSTIC MONITORING TEST RESULTS is available.
PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
FREEZE FRAME DATA is available.
The DTC is stored in the PCM memory.

POSSIBLE CAUSE

Front HO2S deterioration
Front HO2S malfunction
Front HO2S looseness
Pressure regulator (built-in fuel pump unit) malfunction
Fuel pump malfunction
Clogged or restricted fuel filter (built-in fuel pump unit)
Fuel leakage in fuel line between fuel distribution pipe and fuel pump
Exhaust system leakage
Purge solenoid valve malfunction
Improper connection purge solenoid hose
Insufficient compression
Engine malfunction (Engine coolant leakage)