Oxygen Sensor (O2S) Non-Heated

Diagnostic Trouble Code 13:

Oxygen Sensor (O2S) Circuit:

CIRCUIT DESCRIPTION
The PCM applies a bias voltage of approximately 450 millivolts (350-550 mV is normal bias voltage) between terminals "A10" and "A12." The Oxygen Sensor (02S) varies the voltage within a range of about 1 volt if the exhaust is rich, and down to about 0.010 volt if exhaust is lean. DTC 13 is set when the voltage does not vary on CKT 412 within a predetermined amount of time.

The sensor is like an open circuit and produces no voltage when it is below 315°C (600°F). An open sensor circuit, or a cold sensor causes "Open Loop" operation.

DTC 13 WILL SET WHEN
^ Engine has been running longer than 2 minutes.
^ Engine Coolant Temperature (ECT) greater than 70°C (158°F).
^ Throttle Position (TP) signal has been above 5%.
^ 02S signal voltage steady between 0.35 and 0.55 volt.
^ All conditions must be met for about 2 minutes.

ACTION TAKEN (PCM WILL DEFAULT TO)
The Malfunction Indicator Lamp (MIL) will illuminate and system will go into "Open Loop."

DTC 13 WILL CLEAR WHEN
Conditions for fault are no longer present and Tech 1 "clear DTCs" function is used or 50 ignition switch keycycles have passed with no further faults or ignition switch is turned "OFF" and battery feed voltage is removed for 10 seconds.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test verifies operating temperature and "Closed Loop" conditions.

2. This will determine if the sensor is at fault.

3. For this test use J 39200. This test checks the continuity of CKT 412 and CKT 413. If CKT 413 is open, the voltage on CKT 412 will be over 0.6 volt (600 mV).

DIAGNOSTIC AIDS
Normal Tech 1 scan tool voltage varies between 100 mV to 1000 mV (0.1 and 1.0 volt), while in "Closed Loop." DTC 13 sets in one minute if voltage remains between 0.35 and 0.55 volt, however the system will go "Open Loop" in about 15 seconds.

Refer to Diagnosis By Symptom / Intermittents - Intermittent Malfunctions