P0133

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The PCM continuously monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During the monitor period the PCM counts the number of times that the HO2S responds from rich to lean and from lean to rich and adds the amount of time it took to complete all transitions. With this information, an average time for all transitions can be determined. If the average response time is too slow, a DTC will set.

A lean to rich transition is determined when the HO2S voltage changes from less than 300 mV to greater than 600 mV. A rich to lean transition is determined when the HO2S voltage changes from more than 600 mV to less than 300 mV. An HO2S that responds too slowly is most likely defective and should be replaced.

CONDITIONS FOR SETTING THE DTC

^ DTCs P0100, P0107, P0108, P0116, P0117, P0118, P0131, P0132, P0134, P0135, P0171, P0172, P0174, P0175, P0410, P1114, P1115, P1133, not set.

^ Fuel system operating in Closed Loop.

^ Engine speed between 1000 RPM and 1700 RPM.

^ Engine Air Flow between 12 grams per second and 28 grams per second.

^ EVAP Canister purge duty cycle less than 100%.

^ Lean to rich (Below 300 mV to above 600 mV) response average time is greater than 110 Milliseconds or 150 milliseconds if the vehicle is equipped with an L99 engine.

^ Rich to lean (Above 600 mV to below 300 mV) response average time is greater than 110 Milliseconds or 150 milliseconds if the vehicle is equipped with an L99 engine.

^ Above conditions are met for 100 seconds

ACTION TAKEN WHEN THE DTC SETS

^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) on the second consecutive drive trip that the diagnostic runs and fails.

^ The PCM will record operating conditions at the time the diagnostic tails. The first time the diagnostic fails, this information will be stored in Failure Records. It the diagnostic reports a failure on the second consecutive drive trip, the operating conditions at the time of failure will be written to Freeze Frame and the Failure record will be updated.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not tail.

^ A last test tailed (Current DTC) will clear when the ignition is cycled and the diagnostic runs and does not tail.

^ A History DTC will clear after forty consecutive warm-up cycles, it no failures are reported by this or any other emission related diagnostic.

^ PCM battery voltage is interrupted.

^ Using a Scan tool.

DIAGNOSTIC AIDS

^ A malfunction in the HO2S heater circuits will cause a DTC to set. Check HO2S heater circuits for intermittent opens/connections.

^ An oxygen supply inside the HO2S is necessary for proper operation. This supply of oxygen is provided through the HO2S wires. All HO2S wires and connections should be inspected for breaks or contamination.

^ Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that were noted. This will isolate when the DTC tailed. For intermittents, refer to Symptoms. Testing and Inspection

TEST DESCRIPTION

Number(s) below refer to step numbers on the diagnostic table.

2. Determines it the fault is present. This test may take 5 minutes for the diagnostic to run. For any test that requires probing the PCM or a component harness connector, must use the Connector Test Adapter Kit J 35616-A. Using this kit will prevent damage to the harness connector terminals.

3. When DTCs P0133 and P0153 are set at the same time, is good indication that a fuel contamination problem is present.

4. An exhaust leak 6-12 inches away from the HO2S can cause a DTC to set.

5. Checks whether a good ground circuit is available.

6. Checks the integrity of the signal circuit to the PCM.

7. Checks the integrity of the signal circuit to the PCM.

8. Certain RTV silicone gasket materials give off vapors that can contaminate the HO2S. There is also a possibility of silicone contamination caused by silicone in fuel. If it appears that the sensors are contaminated by silicone and all silicone sealant is a none silicone base, advise customer to try a different fuel company. A fuel tiller restrictor missing, indicates leaded fuel may have been used.