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Powertrain fault code

P0174: System Too Lean (Bank 2)

Fix soon

Drivable short-term, but a lean engine can misfire and run hot. Have it checked soon.

What P0174 means

The engine is getting too much air or too little fuel, and the computer has reached the limit of what it can correct.

Common causes

  • Vacuum or intake air leak (cracked hose, intake gasket)
  • Dirty MAF sensor
  • Weak fuel pump or clogged fuel filter
  • Leaking PCV valve or hose

What to check first

  1. Listen for hissing from vacuum hoses with the engine running.
  2. Check the fuel trim numbers on a live scan.
  3. Clean the MAF sensor with proper MAF cleaner.

Get P0174 explained for your car: $2.99

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Read your car's codes yourself, free

Plug a cheap ELM327 OBD-II adapter into the port under the dashboard and open the scan tool: Chrome or Edge on a computer with a USB adapter, or Chrome on Android with a Bluetooth LE adapter. It reads and clears codes and shows emissions readiness. It does not work on iPhone.

Open the free scan tool

Need help with P0174?

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Related codes

P0171

General guidance only, not a diagnosis. A qualified mechanic should confirm the cause before you replace parts.