OBD Guide

P0173

Fuel Trim Bank 2

P0173 is an OBD-II diagnostic trouble code meaning: Fuel Trim Bank 2. Common causes: dirty/defective fuel injectors, vacuum leaks in bank 2. Estimated repair cost: $22–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$22–167 (est.)

Symptoms

  • Increased fuel consumption
  • Unstable idle
  • Reduced engine power
  • Smell of gasoline from the exhaust pipe

Causes

  • Dirty/defective fuel injectors
  • Vacuum leaks in bank 2
  • Malfunction of the mass air flow sensor (MAF)
  • Problems with oxygen sensors
  • Dirty air filter
  • Malfunction of the fuel pump or pressure regulator
  • Leaks in the intake system

How to Fix

  1. Check the system for vacuum leaks (especially bank 2)
  2. Clean or replace the mass air flow sensor
  3. Check oxygen sensor readings
  4. Clean or replace fuel injectors
  5. Check fuel pressure and pump performance
  6. Clean throttle body

Related codes

Error P0173 by Vehicle Brand

FAQ

What does the P0173 code mean?

P0173 is an OBD-II diagnostic trouble code that indicates: Fuel Trim Bank 2

What causes a P0173 error code?

The most common causes of P0173 include: Dirty/defective fuel injectors; Vacuum leaks in bank 2; Malfunction of the mass air flow sensor (MAF); Problems with oxygen sensors.

How do I fix a P0173 diagnostic trouble code?

To fix P0173: Check the system for vacuum leaks (especially bank 2). Clean or replace the mass air flow sensor. Check oxygen sensor readings. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0173?

Limited driving only, diagnose soon

How much does it cost to fix P0173?

The estimated repair cost for P0173 is $22–167. Actual cost depends on your vehicle, location, and labor rates.

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