P0172 - System Too Rich Bank 1

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3    What is this?
Table of contents

P0172 Possible Causes

  • Faulty Front Heated Oxygen Sensor
  • Faulty Spark Plugs
  • Faulty Mass Air Flow (MAF) sensor
  • Exhaust Gas Leaks
  • Ignition Misfiring
  • Incorrect Fuel Pressure
  • Faulty Fuel Injectors

How do I fix code P0172?

Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
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Cost of diagnosing the P0172 code

Labor: 1.0

The cost of diagnosing the P0172 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

When is the code detected?

- Fuel injection system does not operate properly.
- The amount of mixture ratio compensation is too large. (The mixture ratio is too rich.)

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Excessive Fuel Consumption

P0172 Description

With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The Engine Control Module (ECM) calculates the necessary compensation to correct the offset between the actual and the theoretical ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the MIL (2 trip detection logic).
OBDII Code P0172 - System Too Rich Bank 1 - AutoCodes.com

More Information

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