P0133

CIRCUIT DESCRIPTION
Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the vehicle is first started, the powertrain control module (PCM) operates in an open loop mode, ignoring the HO2S signal voltage when calculating the air-to-fuel ratio. The PCM supplies the HO2S with a reference, or bias, voltage of 450 mV. The HO2S generates a voltage within a range of 0-1000 mV, that fluctuates above and below bias voltage once in closed loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. A heating element inside the HO2S reduces the time required for the sensor to reach operating temperature, and provide an accurate voltage signal.

The PCM monitors the rich-to-lean and lean-to-rich HO2S. This DTC will set if the HO2S voltage response time is higher than a calibrated threshold response.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441, or P1621 are not set.
^ The engine coolant temperature (ECT) is more than 70°C (158°F).
^ The battery voltage is more than 10 volts.
^ The fuel level is more than 10 percent.
^ The engine run time is more than 200 seconds.
^ The engine speed is between 1,750-3,500 RPM.
^ The engine is operating in Closed Loop.
^ The throttle position (TP) angle is between 10-30 percent.
^ The evaporative emissions control system is commanded open for more than 36 percent.
^ The purge learned memory is more than approximately 0.78.
^ The diagnostic completes when 30 seconds of accumulated time has been spent in the above conditions.
^ The above conditions are met for more than 2 seconds.

CONDITIONS FOR SETTING THE DTC
The average HO2S 1 response times are more than 875 mS for rich to lean sweeps, or 600 mS for lean to rich sweeps.

Or

Sum of rich-to-lean and lean-to-rich is more than 875 mS.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Clear the MIL and the DTC with a scan tool.

TEST DESCRIPTION

Steps 1-7:

Steps 8-16:

Steps 17-20:

The numbers below refer to the step numbers on the diagnostic table.
2. When the system is operating correctly, the HO2S 1 voltage should toggle above and below the specified values. You may need to operate the vehicle within the Freeze Frame conditions and Conditions for Setting the DTC in order to duplicate the malfunction that was detected by the PCM.
4. The specified value is what is measured on a correctly operating system.
5. The specified value is what is measured on a correctly operating system.