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AutoCodes – Nissan – P1143 Nissan

P1143 Nissan Code - Heated Oxygen Sensor 1 Lean Shift Monitoring Bank 1

Quick Answer

The Heated Oxygen Sensor 1 is placed into the front tube. Common causes include Faulty Front Heated Oxygen Sensor Bank 1, Intake air leaks, Front Heated Oxygen Sensor Bank 1 harness is open or shorted. 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
P1143 Nissan indicates Heated Oxygen Sensor 1 Lean Shift Monitoring Bank 1.
Common causes
Common causes include Faulty Front Heated Oxygen Sensor Bank 1, Intake air leaks, Front Heated Oxygen Sensor Bank 1 harness is open or shorted.
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.
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Code Popularity 54,068
How popular is this code, among other codes? Medium
What is this?
Table of contents Created and updated by William Orellana on May 01, 2019
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Code P1143 Nissan Description

The Heated Oxygen Sensor 1 is placed into the front tube. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 has a closed-end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. The heated oxygen sensor 1 signal is sent to the Engine Control Module (ECM). The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.
OBDII Code P1143 Nissan - Heated Oxygen Sensor 1 Lean Shift Monitoring Bank 1 - AutoCodes.com
P1143 Nissan Code - Heated Oxygen Sensor 1 Lean Shift Monitoring Bank 1
What does this mean?

What are the Possible Causes of the DTC P1143 Nissan?

  • Faulty Front Heated Oxygen Sensor Bank 1
  • Intake air leaks
  • Front Heated Oxygen Sensor Bank 1 harness is open or shorted
  • Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection
  • Fuel pressure
  • Injectors

How to Fix the DTC P1143 Nissan?

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 does this mean?

Code Tech Notes

If there are no intake air leaks, the most likely cause of the P1143 code is the front O2 sensor bank 1.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1143 Nissan 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 P1143 Nissan code?

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Need Help with the Code?

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Information for Specific Nissan Models

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 P1143 Nissan Code

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