P0134

Electrical Diagram:

CIRCUIT DESCRIPTION

The PCM supplies a voltage of about 450 mV between the 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 the exhaust is lean. The PCM monitors and stores the heated oxygen sensor (HO2S) voltage information. The PCM evaluates the HO2S voltage samples in order to determine the amount of time the HO2S voltage was out of range. The PCM compares the stored HO2S voltage samples taken within each sample period and determines 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 P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0125, P0335, P0336, P0351-P0358, P1120, P1220, P1221, P1258 not set

^ The system voltage is greater than 9 volts.

^ The engine run time is greater than 70 seconds.

^ The fuel system is operating in Closed Loop.

^ The AIR and the Catalyst diagnostics are not active.

^ The engine coolant temperature is greater than 48°C (118°F).

^ The HO2S signal voltage is between 350 mV and 550 mV for 57 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM illuminates the Malfunction Indicator Lamp when the diagnostic runs and fails.

^ The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or the Failure Records.

^ Open Loop Fueling.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM turns the MIL OFF after three consecutive drive trip5 that the diagnostic runs and does not fail.

^ A last test failed (current DTC) clears when the diagnostic runs and does not fail.

^ A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.

^ The PCM battery voltage is interrupted.

^ Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS

^ An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provides the supply of oxygen. Inspect the HO2S wires and connections for breaks or contamination. Refer to Body and Accessories/Diagrams.

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

TEST DESCRIPTION

The numbers below refer to the step numbers on the diagnostic table.

2. The engine must be at the normal operating temperature before performing this test. For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616-A. Using this kit prevents damage to the harness connector terminals.

3. Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you can not duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine 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 the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that the PCM recorded. This will isolate when the DTC failed. Refer to Symptoms. Testing and Inspection

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

5. This step checks whether the signal circuit from the PCM is OK.

6. Disconnecting the PCM allows using a DMM J 39200 in order to check continuity of the circuits. This aids in locating an open or shorted circuit.

7. Disconnecting the PCM allows using a DMM J 39200 in order to check continuity of the circuits. This aids in locating an open or shorted circuit.