DTC 13

- Chart - Code 13 Open Oxygen Sensor Circuit.:

- Wiring Diagram for Code 13 Oxygen Sensor Circuit.:

CODE 13, OXYGEN SENSOR CIRCUIT

CIRCUIT DESCRIPTION
Code 13 means an open in the oxygen sensor circuit with the following conditions:
a. Oxygen sensor voltage is within a specified range.
b. Above a specified TPS value.
c. More than a specified time after the engine has warmed up.
The ECM supplies a voltage of about .45V between Terminals "9 and 14". (Voltage may read as low as .32V when measured with a 10 megohm DVM.) The O2 sensor varies the voltage within a range from about 1 volt if the exhaust is rich down through about .1V if exhaust is lean.

CHART DESCRIPTION
1. This step is to determine if the problem is still present.
A normal dwell will vary indicating the fault is not present, while a fixed dwell indicates the fault is still present.
2. By grounding the O2 sensor circuit to the ECM, a "low voltage (lean) signal" is sent to the ECM. If the ECM is not faulty and the circuit is complete a "low voltage signal" should result in a full rich command (low dwell) from the ECM.
3. This step determines if the O2 sensor is functioning. With the rich command, the O2 sensor should read a high voltage, over .8V if it is functional, since the exhaust is rich. If the O2 sensor functions, fault is in the connections to the sensor.