Fuel Injector Quantity
Fuel injector quantity is outside of the normal range.
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 engine computer tracks how much fuel is injected into the engine. If it sees that the amount being used is way too high or low, it triggers this code. This can mean that injectors are malfunctioning or there's a fuel delivery issue.
What the computer is actually seeing
The engine control module (ECM) monitors the fuel quantity delivered via the fuel injectors. It compares the expected injector pulse width and fuel flow rates against actual measurements. If the difference exceeds a preset threshold (often around 10-15% deviation), this fault code is registered.
What a healthy reading looks like
Expected pulse width for fuel injectors typically ranges from 1.5ms to 8ms depending on engine size and load conditions; normal fuel rail pressure is generally between 40 to 60 psi.
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 wiring and connectors for the fuel injectors. Look for frayed wires or corrosion. Are the connections tight?
- 22. Verify fuel pressure at the rail. Is it within the expected 40-60 psi range?
- 33. Inspect the fuel filter. Is it clogged or overdue for a change?
- 44. Test each fuel injector for resistance. Is each one between 12-16 ohms? Swap with a known good injector if necessary.
- 55. Clear the code and run the engine to see if the code returns. Did it come back?
Common causes
- Faulty fuel injectors
- Blocked fuel filter
- Faulty fuel pump
- Low fuel pressure
- Wiring issues to the injectors
- ECM malfunction
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's usually safe for short distances, but fix it soon to prevent potential engine damage.
What happens if the problem comes back?
If it comes back, the issue is likely not resolved; further diagnosis of the fuel system is necessary.
Why do I see this code along with SPN 426?
SPN 426 relates to a different aspect of fuel injection; both indicate potential issues with fuel delivery.
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