P0134

Diagnostic Chart:

Wiring Diagram:

The oxygen sensor consists of a zirconia electrolyte between two platinum plates. When the sensor reaches approximately 318°C (600°F) it becomes an electrical source that responds to the oxygen content in the exhaust. The PCM produces a bias voltage of approximately 470 millivolts on the oxygen sensor circuit. When the sensor is cold its internal resistance is extremely high, therefore, the PCM recognizes the bias as an open circuit. As the sensor warms up, the internal resistance decreases. When the sensor reads approximately 318°C (600°F), it starts producing a voltage based on the oxygen content in the exhaust stream. This voltage is used by the PCM to determine a rich or lean signal and adjust the fuel mixture accordingly.

DTC PARAMETERS

DTC P0134 will set if the 025 voltage is inactive (not reading outside 391-491 mV) for 90 seconds when:

^ The engine is at normal operating temperature (the ECT reads over 60°C [140°F]).
^ The engine has been running at least one minute.
^ The TP sensor reads over 6.5% (the engine is off idle).
^ No other engine sensor or misfire DTCs have been set.
^ Commanded A/F ratio is approximately 14.7 to 1.

NOTE: The 02S signal is continuously checked once the above conditions are met.

DIAGNOSTIC AIDS

The PCM will not go into closed loop if a DTC P0134 has failed during the current ignition cycle.

When attempting to diagnose an intermittent problem, use the Scan tool to review malfunction history diagnostic information. The supplemental data can be used to duplicate a problem.

Check the tightness of the female terminal grip with a spare male terminal.

Normal Scan tool readings in closed loop will show the oxygen sensor voltage varying between 10mV and 999mV.

P0134 can set or cause false oxygen sensor readings if the oxygen sensor ground becomes loose or corroded.