P0134

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The PCM supplies a voltage of about 450 mV between the Heated Oxygen Sensor (HO2S) high and low signal circuits. The oxygen sensor varies the voltage over a range from about 1000 mV when the exhaust is rich, down through about 10 mV when exhaust is lean.

The PCM monitors and stores the heated oxygen sensor (HO2S) voltage information. The PCM evaluates the HO2S voltage samples to determine the amount of time the HO2S voltage was out of range. The PCM will compare the stored HO2S voltage samples taken within each sample period and determine if majority of the samples are out of the operating range.

The PCM monitors the HO2S voltage and detects if the voltage goes out of the bias range. If the PCM does not detect the voltage went out of the bias range, a DTC will set.

CONDITIONS FOR SETTING THE DTC

^ DTCs P0100, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0200, P0372, P1371 not set.

^ Engine operating longer than 68 seconds.

^ Engine coolant temperature greater than 48°C (118°F).

^ HO2S signal voltage steady between 352 mV and 552 mV for 45 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.

^ Open loop fueling.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and/or Failure Records.

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 fail.

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

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

^ PCM battery voltage is interrupted.

^ Using a Scan tool.

DIAGNOSTIC AIDS

^ 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.

^ For intermittents, refer to Symptoms. Testing and Inspection

TEST DESCRIPTION

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

2. Engine must be at normal operating temperature before performing this test. 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. 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. refer to Symptoms. Testing and Inspection

4. If the scan tool indicates the HO2S voltage goes below 200 mV, indicates the HO2S circuits and PCM are OK.

5. Checks whether the signal circuit from the PCM is OK.

6. Disconnecting the PCM will allow using the DVM (J 39200) to check continuity of the circuits. This will aid in locating an open or shorted circuit.

7. Disconnecting the PCM will allow using the DVM (J 39200) to check continuity of the circuits. This will aid in locating an open or shorted circuit.