P1134

CIRCUIT DESCRIPTION
The Heated Oxygen Sensor (HO2S) is a sensor used to detect 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, indicating more oxygen, the sensor produces a low voltage signal. When the exhaust stream is rich, indicating less oxygen, the sensor produces a high voltage signal.

The PCM monitors the HO2S activity to determine a time ratio for the lean to rich and rich to lean switches. A lean to rich switch occurs when the HO2S signal voltage changes from less than 300 mV to more than 600 mV. A rich to lean switch occurs when the HO2S signal voltage switches from more than 600 mV to less than 300 mV. The PCM counts the number of lean to rich and rich to lean switches for 100 seconds. The PCM records the amount of time required to complete all transitions. With this information, the PCM determines an average transition time for the lean to rich switches, and the rich to lean switches. By dividing the rich to lean time by the lean to rich time, the PCM determines the average transition time ratio. This Diagnostic Trouble Code (DTC) indicates that the PCM detects an average transition time ratio that is out of range.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, Pal 17, P0118, P0121, P0122, P0125, P0130, P0132, P0135, P0150, P0152, P0171, P0172, P0175, P0201-P0208, P0300, P0403, P0404, P0405, P0410, P0412, P0418, P0440, P0442, P0443, P0446, P0449, P0560-P0563, P1106, P1107, P1111, P1112, P1114, P1115, P1121, P1122, P1133, P1153, P1404, P1415, or P1416 are not set.
^ The engine speed is between 1,200-2,800 RPM.
^ The Mass Air Flow (MAF) is between 15-35 g/s.
^ The Throttle Position (TP) angle is more than 3 percent.
^ The system voltage is between 9-18 volts.
^ The coolant temperature is above 75°C (167°F).
^ The Closed Loop fuel control is enabled.
^ The Exhaust Gas Recirculation (EGR) flow diagnostic test is not active.
^ The catalyst diagnostic test is not active.
^ The Secondary Air Injection (AIR) diagnostic test is not active.
^ The engine run time is more than 202 seconds.
^ The transmission is not in Park, Reverse, or Neutral.
^ The above conditions exist for 3 seconds.

CONDITIONS FOR SETTING THE DTC
^ The ratio of average transition times is not greater than 3.9 or less than 0.50.
^ The O2 voltage is between 325-625 mV.

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

NOTE: Refer to Heated Oxygen Sensor (HO2S) Wire Repair Notice in Service Precautions.

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

TEST DESCRIPTION

Steps 1-11:

The numbers below refer to the step numbers on the diagnostic table.
2. This step tests if other possible causes of this DTC have already been diagnosed.
3. Diagnose other DTCs first because other DTCs may be the cause of this DTC setting.
4. With the engine running warm and at fast idle, and with the coolant at least 85°C (185°F), the oxygen sensor voltage should rapidly swing above 600 mV and below 300 mV.
6. This step tests if the oxygen sensor voltage is swinging between rich and lean very slowly, or not at all.
9. This step tests for causes of oxygen sensor failure. If the sensor is replaced without finding the cause of contamination, premature failure of the new sensor may result.