Engine-Codes.com
Engine-Codes – Mitsubishi – P0172 Mitsubishi

P0172 Mitsubishi Code - System Too Rich- Cylinders 1-4

Quick Answer

The P0172 Mitsubishi diagnostic trouble code indicates that the engine control module (ECM) has detected a rich air-fuel mixture in cylinders 1-4 of the vehicle's engine. Common causes include Faulty oxygen sensor, Malfunctioning fuel injectors, Clogged air filter. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0172 Mitsubishi indicates System Too Rich- Cylinders 1-4.
Common causes
Common causes include Faulty oxygen sensor, Malfunctioning fuel injectors, Clogged air filter.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 10, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P0172 Mitsubishi Description

The P0172 Mitsubishi diagnostic trouble code indicates that the engine control module (ECM) has detected a rich air-fuel mixture in cylinders 1-4 of the vehicle's engine. This means that there is an excess of fuel being injected into the combustion chamber in relation to the amount of air present, leading to a "rich" condition. This can negatively impact the vehicle's performance, fuel efficiency, and emissions output.

OBDII Code P0172 Mitsubishi - System Too Rich- Cylinders 1-4
P0172 Mitsubishi Code - System Too Rich- Cylinders 1-4

Common Causes of P0172 Mitsubishi

  1. Faulty oxygen sensor
  2. Malfunctioning fuel injectors
  3. Clogged air filter
  4. Faulty mass airflow sensor
  5. Vacuum leak

Symptoms of P0172 Mitsubishi

  1. Reduced fuel efficiency
  2. Rough idling or stalling
  3. Engine misfires
  4. Strong fuel odor from the exhaust
  5. Check Engine Light illuminated

How to Fix P0172 Mitsubishi

  1. Diagnose the root cause of the rich air-fuel mixture by using a scan tool to retrieve the trouble codes and data from the vehicle's ECM.
  2. Inspect and test the oxygen sensor, fuel injectors, air filter, mass airflow sensor, and vacuum lines for any issues or malfunctions.
  3. Replace any faulty components identified during the diagnostic process, such as a defective oxygen sensor or clogged air filter.
  4. Clear the trouble codes from the ECM's memory and test drive the vehicle to ensure that the issue has been resolved.
  5. If the problem persists, further diagnosis may be required to identify any underlying issues that were not initially detected.

Cost to Fix P0172 Mitsubishi

The cost of repairing a rich air-fuel mixture issue can vary depending on the specific cause of the problem and the cost of parts and labor. On average, the repair cost for this issue can range from $200 to $800, including parts and labor. However, it's important to note that the cost can be higher or lower based on the extent of the repairs needed and the rates charged by the auto repair shop. Additionally, diagnosis time and labor rates can vary, so it's recommended to obtain quotes from multiple shops to ensure a competitive price.

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.)

Need more information about the P0172 Mitsubishi code?

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

Need Help with the Code?

Get the P0172 Mitsubishi code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0172 Mitsubishi Code

1. What are the common symptoms of OBDII code P0172 in a Mitsubishi indicating a rich fuel mixture in cylinders 1-4?

Symptoms may include decreased fuel efficiency, black smoke from the exhaust, rough idling, and a strong smell of gasoline.

2. What are the possible causes of OBDII code P0172 in a Mitsubishi?

Potential causes include a faulty oxygen sensor, clogged fuel injectors, a malfunctioning mass airflow sensor, a vacuum leak, or issues with the fuel pressure regulator.

3. How can I diagnose the source of OBDII code P0172 in my Mitsubishi?

To pinpoint the issue, you can perform a thorough inspection of the oxygen sensor, check for any vacuum leaks, test the fuel pressure, clean or replace the fuel injectors, and ensure the mass airflow sensor is functioning correctly.

4. What steps can I take to repair OBDII code P0172 in a Mitsubishi?

Repair options may include replacing a faulty oxygen sensor, cleaning or replacing clogged fuel injectors, fixing any vacuum leaks, repairing or replacing the mass airflow sensor, or addressing issues with the fuel pressure regulator.

5. Is it safe to continue driving my Mitsubishi with OBDII code P0172 present?

It is not recommended to drive your vehicle with a rich fuel mixture, as it can lead to engine damage over time and potentially cause other issues. It's best to address the problem promptly.

6. Can a dirty air filter cause OBDII code P0172 in a Mitsubishi?

Yes, a dirty air filter can disrupt the air-fuel mixture ratio and potentially contribute to a rich condition in cylinders 1-4, triggering OBDII code P0172.

7. Will resetting the OBDII code P0172 in my Mitsubishi make the issue go away?

Resetting the code may temporarily turn off the check engine light, but it will not fix the underlying problem causing the rich fuel mixture. The issue should be diagnosed and repaired to prevent further complications.

8. How often should I check and replace the oxygen sensor in my Mitsubishi to prevent OBDII code P0172?

It is recommended to inspect and replace the oxygen sensor as part of regular maintenance, typically every 60,000 to 90,000 miles, to help prevent issues like OBDII code P0172.

9. Can a failed catalytic converter cause OBDII code P0172 in a Mitsubishi?

A failing catalytic converter can potentially cause a rich fuel mixture by restricting exhaust flow, but it is not a common direct cause of OBDII code P0172 related to cylinders 1-4.

Discuss the causes and fixes for P0172 Mitsubishi OBDII Code

Submit a New Comment

Code P0172 Mitsubishi comments

No comments found for this page.