DTC 13

Oxygen Sensor Circuit:

Code 13 Wiring Diagram:

CIRCUIT DESCRIPTION:

The Oxygen Sensor (02) produces a varying voltage as engine temperature rises to normal operation. This voltage varies from 0 to 900 mV. The signal will vary depending on the content of the exhaust gases. If the voltage stays above 450 mV this indicates a rich condition or voltage remains below 450 mV and does not vary a lean condition is indicated. The 02 Sensor acts like an "open circuit" and produces no voltage when below 360°C (600°F). An open sensor circuit causes the engine to operate in an "open loop" operation.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Running the engine above 1200 rpm keeps the oxygen sensor hot, so that an accurate check of the sensor can be performed.

2. This will check the 02 Sensor.

3. Voltage above 900 mV and not varying indicates a short to voltage on 02 Sensor Circuit.

DIAGNOSTIC AIDS:

Normal voltage varies between 0 mV and 900 mV. Code 13 will set if voltage is indicated low (O volt) or high (9OO mV) all the time.