Fuel Flow Rate - Low
The engine control unit (ECU) detects a fuel flow rate below the desired threshold.
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What it means (plain English)
The computer is seeing that the amount of fuel being delivered to the engine is less than what it expects when you're trying to accelerate.
What the computer is actually seeing
The ECU measures fuel flow rates via various sensors. For instance, if it's expecting a flow of 35-50 liters per hour under specific conditions, but only sees 10 liters per hour, it triggers this code.
What a healthy reading looks like
Fuel flow rates should match specifications, typically around 35-50 liters per hour during acceleration depending on engine load.
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 fuel level in the tank. Is it adequate (above 1/4 tank)? Yes: Proceed. No: Fill the tank and see if the code clears.
- 22. Inspect the fuel lines for visible leaks or damage. Issues found: Repair/replace as needed. No issues: Proceed.
- 33. Check the fuel filter for clogs. Is it clean? Yes: Proceed. No: Replace the fuel filter and see if the code clears.
- 44. Measure voltage at the fuel pump connector while cranking (should be around 12V). Is it present? Yes: Proceed. No: Check electrical issues starting from the relay to the ECU.
- 55. Test the fuel flow sensor with a scan tool or multimeter. Is it within spec? Yes: Possible bad fuel pump. Replace it. No: Replace the fuel flow sensor.
Common causes
- Clogged fuel filter
- Bad fuel pump
- Leaky fuel line or injector
- Faulty fuel flow sensor
- Low fuel level or quality issues
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not dangerous to drive, but your engine performance will suffer, and you should repair it soon.
Will this fault come back after I clear it?
If the underlying issue isn't fixed, the code will likely return after a short period.
Why do I see this paired with SPN 4802?
SPN 4802 is often related, indicating a problem with fuel pressure, which can lead to low flow rates.
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