DTC 44

Code 44 "Oxygen Sensor Circuit:

Wiring Diagram - Oxygen Sensor Circuit:

CODE 44

OXYGEN SENSOR CIRCUIT (LEAN EXHAUST INDICATED)


Circuit Description:

Code 44 indicates that the ECM has monitored the 02 sensor voltage under the following conditions:
Voltage lower than specified and in "Closed Loop"

Within a specified TPS voltage range (part throttle) for a time longer than specified


Test Description: Numbers below refer to circled numbers on the diagnostic chart.

1. System will go "Open Loop" if 02 sensor cools off while idling engine. Scan "Loop" status often during test.

2. Checks to see if the ECM is able to respond to a rich condition caused by choking the engine. If it does, the problem is a lean engine condition NOT electrical.

3. This step puts a rich 02 signal (about 1 volt) into terminal "9" of the ECM. Dwell should increase (lean command).

4. If dwell increases to over 50 degrees, with heavy choking, the fault is an air leak, since the ECM was able to respond. If air is going to exhaust ports, disconnect the solenoid(s) for the air control valve. If air still goes to the ports, it is a faulty valve.


Diagnostic Aids:

Verify proper TPS operation, see CHART C-2F. Check for 02 signal wire shorted to ground. A cylinder misfire may also cause a Code 44. Refer to DIAGNOSIS BY SYMPTOM - NO TROUBLE CODE STORED.