DTC 44

Code 44 Chart:

Code 44 Wiring Diagram:

CIRCUIT DESCRIPTION:

The Electronic Control Module (ECM) supplies a voltage of about 0.45 volt between terminals "GE14" and "GE15." (If measured with a 10 megohm digital voltmeter, this may read as low as 0.32 volt.) The 02 sensor varies the voltage within a range of about 1 volt if the exhaust is rich, down through about 0.10 volt if exhaust is lean. The sensor is like an open circuit and produces no voltage when it is below about 316~C (600~F) An open sensor circuit or cold sensor causes "Open Loop" operation.


TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Code 44 is set when the 02 sensor signal voltage on CKT 412 remains below 0.2 volt for 6O seconds and the system is operating in "Closed Loop".

DIAGNOSTIC AIDS:

^ Using the "Scan", observe the block learn values at different rpm and air flow conditions. The "Scan" also displays the block cells, so the block learn values can be checked in each of the cells to determine when the Code 44 may have been set. If the conditions for Code 44 exists the block learn values will be around 150.

^ 02 Sensor Wire. Sensor pigtail may be mis-positioned and contacting the exhaust manifold. Check for intermittent ground in wire between connector and sensor.



^ Lean Injector(s). Perform injector balance test CHART C-2A.

^ Fuel Contamination. Water, even in small amounts, near the in-tank fuel pump inlet can be delivered to the injectors. The water causes a lean exhaust and can set a Code 44.

^ Fuel Pressure. System will be lean if pressure is too low. It may be necessary to monitor fuel pressure while driving the car at various road speeds and/or loads to confirm, See CHART A-7.

^ Exhaust Leaks. If there is an exhaust leak, the engine can cause outside air to be pulled into the exhaust and past the sensor. Vacuum or crankcase leaks can cause a lean condition.


^ If the above are OK, it is a faulty oxygen sensor.