Fuel Metering Unit Failure
The fuel metering unit has detected a failure in fuel delivery or measurement.
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 fuel metering unit measures how much fuel is delivered to the engine. If it fails, your engine may not get the fuel it needs to run properly, causing poor performance or a no-start condition.
What the computer is actually seeing
The ECM monitors signals from the fuel metering unit for correct fuel flow rates and pressures. If it detects irregularities, such as fuel rail pressure below 4 psi or too high of a fuel return rate, it triggers a fault.
What a healthy reading looks like
Normal fuel rail pressure should be around 20-80 psi depending on engine and load, with fuel return rates within specifications stated in the service manual.
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. Inspect fuel lines and connectors for leaks or damage.
- 22. Check fuel levels in the tank; should be above the minimum.
- 33. Verify fuel filter is clean; replace if contaminated.
- 44. Measure fuel pressure at the rail; should be within 20-80 psi. If not, replace the fuel pump if pressure is low or check metering unit if pressure is high.
- 55. Inspect and test the fuel metering unit for faults; repair or replace as needed.
Common causes
- Clogged fuel filters
- Faulty fuel metering unit
- Wiring issues or bad connections
- Fuel pump malfunction
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, it can lead to engine failure since the fuel delivery is compromised.
Will the code come back after clearing?
If the issue isn’t resolved, it will likely return after a short drive.
Why does it pair with SPN 519?
SPN 519 often relates to the fuel pressure sensor, which is affected by the fuel metering unit's performance.
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