P0133

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) continuously monitors the Heated Oxygen Sensor (HO2S) activity. The PCM counts the number of times that a rich to lean and a lean to rich response is indicated. Then, the PCM adds the amount of time to complete all transitions for a 100 second test period. With this information, an average time for each transition can be determined. If the average response time is too slow, this Diagnostic Trouble Code (DTC) will set. A lean to rich transition is indicated when the HO2S voltage changes from less than 300 mV to more than 600 mV. A rich to lean transition is indicated when the HO2S voltage changes from more than 600 mV to less than 300 mV. An HO2S that responds too slowly is likely to be faulty and should be replaced.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125. P0128, P0201-P0206, P0300, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
^ The engine has been running for more than 4 minutes.
^ The Engine Coolant Temperature (ECT) is more than 50°C (122°F).
^ The engine speed is between 1,000-3,000 RPM.
^ The Mass Air Flow (MAF) is between 13-30 grams per second.
^ The vehicle is in Closed Loop.

CONDITIONS FOR SETTING THE DTC
The HO2S lean-to-rich average transition response time was longer than 63 milliseconds. The rich-to-lean average transition response time was longer than 190 milliseconds.

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.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS
If the condition is intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-11:

Steps 12-16:

The numbers below refer to the step numbers on the diagnostic table.
2. When the system is operating correctly the HO2S voltage should toggle above and below the specified values.
5. If the HO2S low signal circuit is shorted to ground the HO2S voltage will be less than 400 mV when the HO2S high signal circuit is jumped to ground.
6. The specified value is what is measured on a correctly operating system.
7. The specified value is what is measured on a correctly operating system.
14. The new PCM must be programmed.