Exhaust Leaks

WARNING: This page does not describe the selected car, but rather 24 other vehicles, including the 1992 GMC Yukon, 1992 GMC Vandura Special, 1992 GMC Vandura, 1992 GMC Value Van, and 1992 GMC Suburban. However, it is still accessible from the selected car via links, so may be relevant.

If exhaust system has large leaks, exhaust system negative pressure pulses can cause outside air to be drawn into system and past O2 sensor. Vacuum or crankcase leaks can also cause a lean condition. If Code 44 is intermittent, see INTERMITTENTS in TESTS W/O CODES article in this section.

CODE 44 ECM TERMINAL & CIRCUIT WIRING IDENTIFICATION

Application	ECM Terminal	Wire Color
All With 4L80-E
Oxygen Sensor Signal	C14	Purple
Oxygen Sensor Ground	C13	Tan
All Others Except 3.8L
Oxygen Sensor Signal	D7	Purple
Oxygen Sensor Ground	D6	Tan

Fig 1: Code 44, Schematic, Lean Exhaust Indication

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code 44, Flow Chart, Lean Exhaust Indication

Courtesy of GENERAL MOTORS CORP.