P0170 – Fuel Trim Malfunction (Bank 1)

Description

Fuel trim on Bank 1 is outside the acceptable range. Learn how to interpret the correction in our Fuel Trims guide.

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Symptoms

  • Rough idle
  • Hesitation
  • Poor fuel economy
  • Check engine light
  • Weak acceleration

Causes

  • Vacuum leak
  • Faulty MAF sensor
  • Fuel pressure issue
  • Exhaust leak
  • O2/AFR imbalance

Diagnosis

  • Check fuel trims
  • Inspect for vacuum leaks
  • Test MAF sensor
  • Measure fuel pressure
  • Check exhaust leaks

Repair

  • Repair vacuum leaks
  • Replace MAF sensor
  • Fix fuel pressure issues
  • Repair exhaust leaks
  • Recalibrate fuel trims

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