P1133

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematic:

CIRCUIT DESCRIPTION
The 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 lean to rich thresholds. A lean to rich switch is determined when the HO2S voltage changes from less than 300 mV to greater 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
^ No TP sensor, EVAP system, misfire, IAT sensor, MAP sensor, Fuel trim, injector circuit, EGR Pintle Position, MAF sensor, ECT sensor, CKP sensor, or HO2S sensor 1 heater circuit DTCs set.
^ Mass Air Flow is between 10 g/s and 30 g/s.
^ ECT is greater than 50°C (122°F).
^ Engine run time is greater than 60 seconds.
^ Engine speed is between 1000 RPM and 3000 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 PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
^ The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
A malfunction in the HO2S heater ignition feed or ground circuit may cause the DTC to set. Inspect HO2S heater circuitry for intermittent malfunctions or poor connections. If connections and wiring are OK and the DTC continues to set, replace the HO2S 1.

IMPORTANT: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

^ Poor terminal connection.
Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Diagrams for diagnosis and repair.
^ Damaged harness.
Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Diagrams for diagnosis and repair.
^ Inspect the PCM and the engine grounds for clean and secure connections.

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.

TEST DESCRIPTION
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 low circuit is shorted to ground the HO2S voltage will be less than 400 mV when the 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. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.