AutoCodes – Mercury – P2243 Mercury

P2243 Mercury Code - O2 Sensor Reference Voltage Circuit Open Bank 1 Sensor 1

Quick Answer

The Front Heated Oxygen Sensor (or O2 sensor 1) is placed into the exhaust manifold. Common causes include Faulty Front Heated Oxygen Sensor Bank 1, Front Heated Oxygen Sensor Bank 1 harness is open or shorted, Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P2243 Mercury indicates O2 Sensor Reference Voltage Circuit Open Bank 1 Sensor 1.
Common causes: Common causes include Faulty Front Heated Oxygen Sensor Bank 1, Front Heated Oxygen Sensor Bank 1 harness is open or shorted, Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 1,728

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Dec 28, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P2243 Mercury Description

The Front Heated Oxygen Sensor (or O2 sensor 1) is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The Powertrain Control Module (PCM) monitors the universal heated oxygen sensor (HO2S) for a circuit concern. This Diagnostic Trouble Code (DTC) sets when the PCM detects a concern with the circuit used to determine the oxygen content in the exhaust gas.

OBDII Code P2243 Mercury - O2 Sensor Reference Voltage Circuit Open Bank 1 Sensor 1 - AutoCodes.com — P2243 Mercury Code - O2 Sensor Reference Voltage Circuit Open Bank 1 Sensor 1

What does this mean?

What are the Possible Causes of the DTC P2243 Mercury?

Faulty Front Heated Oxygen Sensor Bank 1
Front Heated Oxygen Sensor Bank 1 harness is open or shorted
Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection

How to Fix the DTC P2243 Mercury?

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 P2243 Mercury 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.

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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.