P0133

CIRCUIT DESCRIPTION
The heated oxygen sensor (HO2S) is a sensor used in order to detect the oxygen content in the exhaust. The powertrain control module (PCM) supplies the sensor with a signal circuit and a ground circuit. The PCM supplies a bias voltage between the circuits. The sensor varies the voltage based on the oxygen content in the exhaust. When the exhaust stream is lean (more oxygen), the sensor produces a low voltage signal. When the exhaust stream is rich (less oxygen), the sensor produces a high voltage signal. The PCM monitors the HO2S signal during Closed Loop. To correct for rich or lean conditions, the PCM adjusts the injector pulse width.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0135, P0151, P0152, P0201-P0208, P0300, P0410, P0410, P0418, P0419, P0440, P0442, P0443, P0446, P0449, P1133, P1415, P1416, or P1441 are not set.
^ The engine speed is between 1,200-2,300 RPM.
^ The throttle position (TP) angle is more than 3 percent.
^ The mass air flow (MAF) is between 15-35 g/s.
^ The system voltage is between 9-18 volts.
^ The coolant temperature is more than 68°C (154°F).
^ The transmission is not in Park, in Reverse, or in Neutral.
^ The catalyst diagnostic test is not active.
^ The engine run time is more than 200 seconds.
^ The EGR flow diagnostic test is not active.
^ The AIR diagnostic test not active.
^ The Closed Loop fuel enabled.
^ The above conditions are met for 3 seconds.

CONDITIONS FOR SETTING THE DTC
^ The HO2S bank 1 sensor 1 lean-to-rich average transition response time during the sample period was longer than 219 milliseconds.

or

^ The HO2S bank 1 sensor 1 rich-to-lean average transition response time during the sample period was longer than 219 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.
^ Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS

NOTE:
^ Refer to Heated Oxygen Sensor (HO2S) Wire Repair Notice in Service Precautions.
^ Refer to Connector Test Adapter kit J 35616-A Notice in Service Precautions.

Check for the following conditions:
^ Inspect the harness connectors for backed-out terminals, for improper mating, for broken locks, for improperly formed or damaged terminals, and for poor terminal-to-wire connections. Refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.
^ A damaged harness-Inspect the wiring harness for damage. If the harness appears to be OK, observe the scan tool while moving connectors and wiring harnesses related to the HO2S bank 1 sensor. A change in the display will indicate the location of the malfunction. Refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.
^ For intermittent conditions, refer to Symptoms - Computers and Controls Systems. Symptom Related Diagnostic Procedures

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help to diagnose the condition. The information may help determine how often the condition that set the DTC occurs.

TEST DESCRIPTION

Steps 1-8:

Steps 9-14:

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. The specified value is what is measured on a correctly-operating system.
6. The specified value is what is measured on a correctly-operating system.