AutoCodes – Infiniti – P0172 Infiniti

P0172 Infiniti Code - Fuel Injection System Too Rich Bank 1

Quick Answer

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. Common causes include Faulty Front Heated Oxygen Sensor, Faulty Spark Plugs, Faulty Mass Air Flow (MAF) sensor. 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 Infiniti indicates Fuel Injection System Too Rich Bank 1.
Common causes: Common causes include Faulty Front Heated Oxygen Sensor, Faulty Spark Plugs, Faulty Mass Air Flow (MAF) sensor.
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.

Save to My Repairs Step-by-Step Diagnostic Guide My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 20,008

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 02, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0172 Infiniti 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 Infiniti - Fuel Injection System Too Rich Bank 1 - AutoCodes.com — P0172 Infiniti Code - Fuel Injection System Too Rich Bank 1

What does this mean?

What are the Possible Causes of the DTC P0172 Infiniti?

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 to Fix the DTC P0172 Infiniti?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0172 Infiniti code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0172 Infiniti code?

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

Need Help with the Code?

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

Information for Specific Infiniti Models

P0172 2003 Infiniti G35 — Fuel Injection System Too Rich Bank 1
P0172 2004 Infiniti G35 — Fuel Injection System Too Rich Bank 1
P0172 2005 Infiniti G35 — Fuel Injection System Too Rich Bank 1
P0172 2006 Infiniti G35 — Fuel Injection System Too Rich Bank 1

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.