Air Mass Sensor Signal Voltage Low
The air mass sensor is reporting a voltage that is too low.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The air mass sensor measures the amount of air going into the engine; if it's not sending enough voltage, the engine control module (ECM) might think there's less air than there actually is, which could lead to poor engine performance.
What the computer is actually seeing
The ECM expects a certain voltage from the air mass sensor, typically between 0.5 to 4.5 volts under normal conditions. When it reads below 0.5 volts, it triggers SPN 2773.
What a healthy reading looks like
Normal voltage values from the air mass sensor range from 0.5 to 4.5 volts depending on engine load and speed.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the air mass sensor connector for damage or corrosion. Repair as needed.
- 22. Inspect the wiring between the air mass sensor and the ECM for shorts or opens. Replace if damaged.
- 33. With the engine running, use a scan tool to monitor the air mass sensor voltage. It should be between 0.5 and 4.5 volts.
- 44. If the voltage is below 0.5 volts, replace the air mass sensor and retest.
- 55. If the voltage is normal, proceed to check for vacuum leaks using a smoke test.
- 66. Clear the fault code and do a test drive to confirm the issue is resolved.
Common causes
- Faulty air mass sensor
- Damaged wiring or connectors
- Vacuum leaks
- Dirty air filter
- Inlet obstruction
Typical repair cost
$$ - $$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable, but expect reduced power and fuel efficiency until fixed.
Will this code come back after clearing?
If the underlying issue isn't resolved, yes, it will return.
Why does this code pair with others?
Related codes may indicate problems with air intake or sensor reliability.
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