Exhaust Leaks

1995 Chevrolet Forward Control 4.3 Z, AutomaticSECTION Exhaust Leaks

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, proceed to the INTERMITTENTS in TESTS W/O CODES - GASOLINE article.

CODE 44 TERMINAL & CIRCUIT WIRING IDENTIFICATION

Engine Application ECM/PCM Terminal Wire Color
"C" & "K" Series
5.0L A/T
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
5.0L M/T
Oxygen Sensor Signal D7 Purple
Oxygen Sensor Ground D6 Tan
Fig 1: Code 44 Schematic (5.0L) Lean Exhaust Indication
G91H07378
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.