CODE 13, OPEN OXYGEN SENSOR CIRCUIT GMC Suburban I

CODE 13, OPEN OXYGEN SENSOR CIRCUIT

When exhaust temperature is less than 600°F (316°C), O2 sensor is open and produces no voltage. An open sensor circuit or cold sensor will not allow system to enter closed loop. On some models, oxygen sensor is equipped with an internal heating unit. This allows sensor to reach operating temperature quicker and maintain closed loop operation even during extended idle. Heating element resistance should be 3.5-14 ohms at 662°F (350°C).

Note. Test numbers refer to test numbers on diagnostic chart.

1. Code 13 will set at normal operating temperature if at least 2 minutes have passed since engine start, Code 21 or 22 is not present, O2 signal voltage is steady at .35-.55 volt and throttle position sensor signal is greater than idle. All conditions must be met for at least one minute.
2. This determines if fault is in O2 sensor, control module or wiring.
3. Use only a high-impedance Digital Volt-Ohmmeter (DVOM) while checking for continuity in signal and ground circuits. If ground circuit is open, voltage on signal circuit will be greater than .6 volt.

Verify a clean, tight connection for sensor ground. An open circuit at sensor signal terminal or ground terminal will result in a Code 13.

CODE 13 TERMINAL & CIRCUIT WIRING IDENTIFICATION

Code 13 Schematic (All Models) Open Oxygen Sensor Circuit. Scheme 293

Code 13 Flow Chart (All Models) Open Oxygen Sensor Circuit. Scheme 294