Engine-CodesInfiniti – P1273 Infiniti

P1273 Infiniti Code - Air Fuel Ratio Sensor 1 Bank 1 Lean Shift Monitoring

Quick Answer

The P1273 Infiniti code indicates an issue with the Air Fuel Ratio Sensor 1 on Bank 1, specifically related to lean shift monitoring. Common causes include Faulty Air Fuel Ratio Sensor 1, Vacuum leaks in the intake system, Clogged fuel injectors. 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
P1273 Infiniti indicates Air Fuel Ratio Sensor 1 Bank 1 Lean Shift Monitoring.
Common causes
Common causes include Faulty Air Fuel Ratio Sensor 1, Vacuum leaks in the intake system, Clogged fuel injectors.
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.
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code P1273 Infiniti Description

The P1273 Infiniti code indicates an issue with the Air Fuel Ratio Sensor 1 on Bank 1, specifically related to lean shift monitoring. This sensor is responsible for monitoring the air-fuel mixture entering the engine and ensuring it is at the optimal ratio for combustion. When the sensor detects a lean condition, meaning there is too much air and not enough fuel in the mixture, it triggers this diagnostic trouble code. A lean air-fuel ratio can lead to poor engine performance, reduced fuel efficiency, and potential damage to the engine over time.

OBDII Code P1273 Infiniti - Air Fuel Ratio Sensor 1 Bank 1 Lean Shift Monitoring
P1273 Infiniti Code - Air Fuel Ratio Sensor 1 Bank 1 Lean Shift Monitoring

Common Causes of P1273 Infiniti

  1. Faulty Air Fuel Ratio Sensor 1
  2. Vacuum leaks in the intake system
  3. Clogged fuel injectors
  4. Issues with the fuel pressure regulator
  5. Exhaust leaks near the sensor

Symptoms of P1273 Infiniti

  1. Decreased fuel efficiency
  2. Rough idling or stalling
  3. Engine misfires
  4. Difficulty starting the vehicle
  5. Check Engine Light illuminated on the dashboard

How to Fix P1273 Infiniti

  1. Use an OBD-II scanner to confirm the P1273 code and pinpoint the issue
  2. Inspect the Air Fuel Ratio Sensor 1 on Bank 1 for any damage or contamination
  3. Check for vacuum leaks and repair or replace any damaged hoses
  4. Clean or replace clogged fuel injectors
  5. Test the fuel pressure regulator and replace if necessary

Cost to Fix P1273 Infiniti

The cost of repairing a P1273 Infiniti code can vary depending on the specific cause of the issue. In general, replacing the Air Fuel Ratio Sensor 1 can cost between $100 and $300 for the part alone. Labor costs at an auto repair shop can range from $100 to $200 per hour, and additional costs for diagnostic testing and any other necessary repairs should be factored in. Overall, the total repair cost for this issue can range from $200 to $600 or more, depending on the extent of the problem and the shop's rates.

Tech Notes for P1273 Infiniti

If one or more sensors are replaced the Engine Control Module (ECM) Mixture Ratio Self-Learning clearing procedure must be performed.

There is a Factory Service Bulletin for the following Infiniti models:
2003-2012 Infiniti FX
2002 Infiniti G20
2003-2006 Infiniti G35 Sedan
2003-2007 Infiniti G35 Coupe
2006-2012 Infiniti G37 Sedan
2008-2012 Infiniti G37 Coupe
2002-2004 Infiniti I35
2004-2012 Infiniti M
2002-2006 Infiniti Q45
2002-2003 Infiniti QX4
2004-2012 Infiniti QX56
Infiniti Factory Service Bulletin OBDII Code P1273

When is the Code Detected?

The output voltage computed by ECM from the A/F sensor 1 (Bank 1) signal is shifted to the lean side for a specified period.

Need more information about the P1273 Infiniti code?

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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 P1273 Infiniti Code

No Frequently Asked Questions about P1273 Infiniti Code found.

Discuss the causes and fixes for P1273 Infiniti OBDII Code

  • I will like to know does Bank 1 means (upstream or downstream left and right) cos am having thesame issue with my mum infinite FX 2005 too and its says Air Flow System Sensor Failure Bank 1

  • What does bank mean: https://www.autocodes.com/a...

    Do you have an FX45 or FX35?

  • I HAVE THE SAME FX35 HAVING SAME ISSUE
    CAN YOU HELP PLEASE?

    smoke tested no leaks except waay in the back after both sensors from muffler
    new spark plugs and new a/f sensor
    car runs smooth though

  • If you already replaced the A/F sensor and there are no leaks, then the next step is to clean or replace the Mass Air Flow (MAF) sensor.

  • I have and the Check engine like keeps coming back every 60 -70 miles