OBD Codes

P0172

System Too Rich (Bank 1)

Moderatefuel system

Overview

The P0172 code indicates a system too rich (bank 1) condition has been detected by the vehicle's powertrain control module (PCM). This code relates to the fuel delivery and metering system, which is responsible for providing the correct amount of fuel to the engine. When this code is stored, the fuel system is not operating within the expected parameters, which can affect engine performance and fuel economy.

Symptoms

  • Reduced fuel economy
  • Engine hesitation during acceleration
  • Strong fuel odor from the engine bay
  • Black smoke from exhaust

Common Causes

  • Failed fuel pump or weak fuel pressure
  • Faulty fuel volume regulator control solenoid
  • Clogged or dirty fuel filter
  • Faulty PCM (Powertrain Control Module)

Diagnosis Steps

  1. 1Connect an OBD-II scanner and read all stored trouble codes and freeze frame data
  2. 2Check fuel pressure using a fuel pressure gauge; compare to manufacturer specifications
  3. 3Inspect fuel lines, connections, and injectors for leaks or damage
  4. 4Test the fuel pressure regulator for proper operation
  5. 5Check the fuel pump relay and electrical connections

Estimated Repair Cost

$150$800

Cost varies by vehicle, location, and repair shop. Includes parts and labor.

Commonly Affected Vehicles

Hyundai SonataBMW 3 SeriesFord F-150Kia Optima

Related Codes

More Fuel System Codes

Frequently Asked Questions

It depends on the severity. Minor sensor issues may allow short-distance driving, but fuel pressure or leak codes should be addressed immediately as they can cause stalling, engine damage, or fire hazards.