P1133

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this test period, the PCM counts the number of times that the HO2S signal voltage crosses the rich-to-lean and the lean-to-rich thresholds. A lean-to-rich switch is determined when the HO2S voltage changes from less than 300 mV to more than 600 mV. A rich-to-lean switch is determined when the HO2S voltage changes from more than 600 mV to less than 300 mV. If the PCM determines that the HO2S did not switch enough times, DTC P1133 will set.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
^ The Mass Air Flow (MAF) is between 10-30 g/s.
^ The Engine Coolant Temperature (ECT) is more than 50°C (122°F).
^ The engine run time is more than 60 seconds.
^ The engine speed is between 1,000-3,000 RPM.
^ The engine is running in closed loop.

CONDITIONS FOR SETTING THE DTC
^ The above conditions are present for a 100 second monitoring period.
^ The PCM monitors fewer than 40 rich-to-lean and 40 lean-to-rich switches for HO2S 1.

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 DTC
^ 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 non-emission related diagnostic.
^ Use a scan tool in order to clear the DTC.

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.