Engine-Codes - Toyota - P0172 2009 Toyota Prius

P0172 2009 Toyota Prius Code - System Too Rich Bank 1

- Code Popularity: 5,111 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents
ChatAC AutoCodes.com AI Chat

What are the Possible Causes of the DTC P0172 2009 Toyota Prius?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty front heated oxygen sensor
  • Ignition misfiring
  • Faulty fuel injectors
  • Exhaust gas leaks
  • Incorrect fuel pressure
  • Faulty Mass Air Flow (MAF) sensor
  • EFI M relay
  • ECM
⚠ Does your Toyota have Safety Recalls? → Check here

How to Fix the DTC P0172 2009 Toyota Prius?

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 pins.

Search for P0172 2009 Toyota Prius Questions and Answers: Search here →

What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0172 2009 Toyota Prius code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair 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.)

What are Code Possible Symptoms?

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

What Does the P0172 2009 Toyota Prius Code Mean?

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).

P0172 2009 Toyota Prius Code - System Too Rich Bank 1

Need more Information on the Code?

Need more information on how to fix the P0172 2009 Toyota Prius code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0172 2009 Toyota Prius code diagnosed by a professional: Find a repair shop in your area