DTC 13

DTC 13 Chart:

Left (Bank 2) Oxygen Sensor Circuit:

Circuit Description:
The PCM supplies a voltage of about 45 volt between terminals "B20" and "B21." (If measured with a 10 megohm digital voltmeter, this may read as low as .35 volt.) The Oxygen Sensor (O2S) varies the voltage within a range of about 1 volt. If the left (Bank 2) exhaust is rich, the 02S will display close to 1000 millivolts and when the exhaust is lean the 02S will display close to 100 millivolts.
The sensor is like an open circuit and produces no voltage when it is below 316°C (600°F). An open 02S circuit or cold O2S causes "Open Loop" operation.

DTC 13 Will Set When:
The engine is in "Closed Loop," ECT is greater than 85°C (185°F), 02S voltage is between 350 and 550 millivolts, throttle angle is greater than 3% with all conditions met for 30 seconds.

Action Taken (PCM will default to):
The PCM will default to "Open Loop" operation and the MIL will become illuminated.

DTC 13 Will Clear When:
A current DTC 13 will clear when the 02S voltage begins to vary outside of the 350 to 550 millivolt window. A history DTC 13 will clear after 50 ignition key cycles without a current DTC 13 being stored.

Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.

1. If the conditions for a DTC 13 exist, the system will not go "Closed Loop."

2. This will determine if the sensor is at fault, or the wiring or PCM is the cause of the DTC 13.

3. In doing this test use only a high impedance digital volt ohmmeter. This test checks the continuity of CKT 1665 and CKT 351 because if CKT 351 is open, the PCM voltage on CKT 1665 will be over .6 volt (600 mV).

Diagnostic Aids:
Normal Tech 1 scan voltage varies between 100 mV to 999 mV (.1 and 1.0 volt) while in "Closed Loop." DTC 13 sets if voltage remains between .35 and .55 volt, but the system will go "Open Loop" in about 15 seconds. Refer to "Intermittents," in "Diagnosis By Symptom." - Intermittent Malfunctions