Exhaust Leaks

If the exhaust system has large leaks, exhaust system negative pressure pulses can cause outside air to be drawn into the system and past the O2 sensor. Vacuum or crankcase leaks can also cause a lean condition.

If Code 44 is intermittent, see INTERMITTENTS in H - TESTING W/O CODES article.

Fig 1: Code 44: Flow Chart Lean Exhaust Indication