OBD
P218F
Reductant No Flow Detected
What it means
P218F stands for Reductant No Flow Detected. P218F is a P code, so the fault sits in the engine, transmission and emissions systems. For P218F, the second digit places it in fuel and air metering. For P218F, work through the cause list below, cheapest checks first.
What to check first
For P218F, clear the code, drive a short distance and read it again, since a code that comes back is still there and one that does not was history.
Check these first
- P218F: Faulty or contaminated sensor in the fuel/air metering circuit
- P218F: Damaged or shorted wiring or connector for the affected circuit
- P218F: Vacuum leak or intake system restriction
- P218F: Failing fuel pump, injector, or fuel pressure regulator
What to do next
P218F is a fault in the fuel and air metering system. The steps below are general, so what actually failed on your vehicle may not be what P218F names.
- P218F: Read freeze frame data and related codes with an OBD-II scanner
- P218F: Inspect the affected sensor wiring and connector for damage
- P218F: Compare live sensor readings (fuel trim, airflow, temperatures) to manufacturer specs
- P218F: Smoke test the intake system if lean or vacuum conditions are suspected
- P218F: Replace the failed component after confirming it with live data
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Updated
Generic SAE J2012 definition. Last updated 2026-08-30.