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Code 44 - Lean Exhaust Indication

Code 44 indicates that the ECM has seen O2 sensor voltage lower than .2 volts for 8 seconds or more, 2 minutes after engine start. The ECM supplies a voltage of about .45 volt between terms. "8" and "15" (2.0L--"D7" and "D8"). The O2 sensor varies the voltage from 1 volt (rich indication) to .10 volt (lean indication). An open sensor circuit or a bad sensor causes open loop operation.

NOTE: The following step numbers refer to the numbers in the accompanying flow chart(s).
  1. This test allows the ECM to confirm either open or closed loop operation.
  2. A light out or "open loop" indicates presence of fault. Disconnecting the O2 sensor will raise the signal voltage above .2 volt. If the ECM and wiring are good, the ECM should recognize the higher voltage, .35 to .55 volt, and flash "open loop" when the engine is started.
  3. Code 44 may be set by any of the conditions listed in the chart. If these systems are found to be operating, O2 sensor is faulty.
Fig 1: Code 44, Lean Exhaust Indication Flow Chart
G4733
Fig 2: Code 44, Lean Exhaust Indication Flow Chart
GB0048025