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Powertrain fault code

P0172: System Too Rich (Bank 1)

Fix soon

Drivable short-term, but fuel use rises and the catalytic converter can be damaged.

What P0172 means

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

Common causes

  • Leaking injector
  • Fuel pressure too high
  • Dirty MAF sensor or blocked air filter
  • Faulty coolant temperature sensor

What to check first

  1. Check the air filter.
  2. Check the fuel trim numbers on a live scan.
  3. Have fuel pressure and injectors tested.

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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.

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Related codes

P0175

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