GM 44 Oxygen Sensor Error Lean Condition Indicated
How to read it
Code 44 reads as 4 flashes, pause, 4 flashes on the check-engine light. Jump terminals A and B on the ALDL connector with the key off, then turn the key on with the engine off and count the check-engine flashes.
New to flash codes? The How to Read GM OBD-I Codes with a Paperclip walks through the test and what the numbers mean. The general OBD-I guide covers the rest.
What does GM code 44 mean?
Oxygen Sensor Error Lean Condition Indicated
Common causes of 44
- Vacuum leak leaning the mixture
- Low fuel pressure from a weak pump or clogged filter
- Dirty fuel injectors with poor spray
- Exhaust leak ahead of the sensor skewing the reading
How to fix 44
- Check fuel pressure against specification under load
- Inspect vacuum hoses and intake gaskets for leaks
- Watch oxygen sensor cross counts on a scan tool through the ALDL port
- Repair leaks and fuel delivery faults before replacing the sensor
- Replace the sensor only if it stays lean with fuel trim and pressure normal
Sources and review
Review: qualified. Read the source limits below.
- GM OBD1 trouble codes, model and year page
live reference page (troublecodes.net)
Supports: code identity and GM meaning
Fetched directly from the linked model page. Single publisher, so the record is qualified, not verified.
Last updated 2026-09-19.
Report a correction for 44. Include your vehicle, the issue and a source if you have one.