What is the general information about Oxygen Sensor and their role on Mercury Mariner?

An oxygen sensor functions as a galvanic battery that generates a small voltage output based on the oxygen levels in exhaust gases, providing essential input for the feedback loop with the Powertrain Control Module (PCM) to maintain the ideal air/fuel ratio of 14.7:1 for optimal catalyst performance. Vehicles equipped with On-Board Diagnostics II (OBD-II) utilize two Oxygen Sensor-one before and one after the catalytic converter-to assess converter efficiency by comparing oxygen levels in the exhaust gases. Four-cylinder models feature one upstream and one downstream heated oxygen sensor, while V6 models have four heated sensors, with two for each cylinder head and multiple catalysts. All sensors are heated to reduce warm-up time, and care must be taken during servicing to avoid damaging the permanently attached pigtail and electrical connector, as well as to keep contaminants away from the sensor. When replacing an oxygen sensor, it is advisable to warm the engine to ease removal, apply anti-seize compound to the threads if reusing an old sensor, and ensure proper torque during installation. After reconnecting the battery, the PCM must relearn its idle and fuel trim strategy for optimal performance.

Genuine Mercury Mariner Oxygen Sensor

Oxygen O2 Sensor

Select Vehicle by Model
Select Vehicle by VIN

Select Vehicle by Model

Make

Model

Year

Select Vehicle by VIN

For the most accurate results, select vehicle by your VIN (Vehicle Identification Number).

21 Oxygen Sensors found

View related parts
Mercury Mariner Lower Oxygen Sensor
Part Number: BE5Z-9G444-A
$72.47 MSRP: $117.38
You Save: $44.91 (39%)
Ships in 1 Business Day
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen
- Position: Front
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2011 Mercury Mariner | 4 Cyl 2.5L PFI Gas/Electric, 6 Cyl 3.0L OHC Duratec | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Hego Sensor
Part Number: 5C5Z-9F472-AA
$58.47 MSRP: $94.73
You Save: $36.26 (39%)
Ships in 1 Business Day
ADD TO CART
Product Specifications
- Other Name: Sensor - Hego
- Position: Passenger Side
- Replaced by: GU2Z-9G444-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2007-2008 Mercury Mariner | 6 Cyl 3.0L DOHC EFI Modular | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Lower Oxygen Sensor
Part Number: BE5Z-9G444-B
$80.86 MSRP: $114.76
You Save: $33.90 (30%)
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen
- Manufacturer Note: Rear
- Position: Passenger Side
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2011 Mercury Mariner | 6 Cyl 3.0L OHC Duratec | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Front Oxygen Sensor
Part Number: 5L8Z-9F472-BA
$60.60 MSRP: $98.16
You Save: $37.56 (39%)
Ships in 1 Business Day
ADD TO CART
Product Specifications
- Other Name: Sensor - Hego
- Manufacturer Note: Rear
- Position: Front
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2005-2010 Mercury Mariner | 4 Cyl 2.3L, 4 Cyl 2.3L Hybrid Gas/Electric DOHC, 4 Cyl 2.5L Duratec (110kW/150PS) | 4AT CD4E, 5-Speed Manual Transmission, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Four-Wheel Drive (Right Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive, Two-Wheel Drive (Left Hand Drive), Two-Wheel Drive (Right Hand Drive)
View related parts
Mercury Mariner Front Oxygen Sensor
Part Number: 8F9Z-9F472-B
$101.69 MSRP: $164.73
You Save: $63.04 (39%)
Ships in 1 Business Day
ADD TO CART
Product Specifications
- Other Name: Sensor - Hego
- Manufacturer Note: Front Or Rear
- Position: Upper
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2009-2011 Mercury Mariner | 4 Cyl 2.5L PFI Gas/Electric | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Front Oxygen Sensor
Part Number: 9E5Z-9F472-D
$99.42 MSRP: $161.05
You Save: $61.63 (39%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Sensor - Hego
- Position: Front And Rear
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2010-2011 Mercury Mariner | 6 Cyl 3.0L OHC Duratec | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Front Oxygen Sensor
Part Number: 5L8Z-9F472-AA
$60.45 MSRP: $84.13
You Save: $23.68 (29%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Sensor - Hego
- Manufacturer Note: Rear
- Position: Front
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2009 Mercury Mariner | 6 Cyl 3.0L OHC Duratec | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Oxygen Exhaust Gas Sensor
Part Number: 5W6Z-9G444-BA
$58.47 MSRP: $94.73
You Save: $36.26 (39%)
Ships in 1 Business Day
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen
- Position: Front
- Replaced by: GU2Z-9G444-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2008-2010 Mercury Mariner | 4 Cyl 2.3L, 4 Cyl 2.5L PFI Gas/Electric, 6 Cyl 3.0L OHC Duratec | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
- 2005-2006 Mercury Mariner | 4 Cyl 2.3L | 4AT CD4E, 5-Speed Manual Transmission, 5-Speed Manual Transmission - AK, Four-Wheel Drive (Full Time) (Left Hand Drive), Four-Wheel Drive (Right Hand Drive), Left Hand Drive, Two-Wheel Drive (Left Hand Drive), Two-Wheel Drive (Right Hand Drive)
View related parts
Mercury Mariner Lower Oxygen Sensor
Part Number: 5L8Z-9G444-F
$59.44 MSRP: $96.29
You Save: $36.85 (39%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen
- Manufacturer Note: Rear
- Replaces: 5L8Z-9G444-H, 5L8Z-9G444-J
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2007-2010 Mercury Mariner | 6 Cyl 3.0L DOHC EFI Modular, 6 Cyl 3.0L OHC Duratec | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Lower Oxygen Sensor
Part Number: 5L8Z-9G444-K
$49.51 MSRP: $83.35
You Save: $33.84 (41%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen; Lower Oxygen Sensor, Oxygen Sensor
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2009-2010 Mercury Mariner | 4 Cyl 2.5L Duratec (110kW/150PS) | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Lower Oxygen Sensor
Part Number: BL8Z-9G444-A
$92.82 MSRP: $150.36
You Save: $57.54 (39%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen; Lower Oxygen Sensor, Oxygen Sensor
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2011 Mercury Mariner | 4 Cyl 2.5L Duratec (110kW/150PS) | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Hego Sensor
Part Number: XC2Z-9F472-AA
$58.47 MSRP: $94.73
You Save: $36.26 (39%)
Ships in 1 Business Day
ADD TO CART
Product Specifications
- Other Name: Sensor - Hego
- Position: Passenger Side
- Replaced by: GU2Z-9G444-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2005-2006 Mercury Mariner | 6 Cyl 3.0L DOHC EFI Modular | 4AT CD4E, 5-Speed Manual Transmission, 5-Speed Manual Transmission - AK, Four-Wheel Drive (Full Time) (Left Hand Drive), Four-Wheel Drive (Right Hand Drive), Left Hand Drive, Two-Wheel Drive (Left Hand Drive), Two-Wheel Drive (Right Hand Drive)
View related parts
Mercury Mariner Sensor Assembly
Part Number: YL8Z-9G444-CA
$59.94 MSRP: $97.09
You Save: $37.15 (39%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Position: Passenger Side
- Replaced by: 5L8Z-9G444-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2005-2006 Mercury Mariner | 6 Cyl 3.0L DOHC EFI Modular | 4AT CD4E, 5-Speed Manual Transmission, 5-Speed Manual Transmission - AK, Four-Wheel Drive (Full Time) (Left Hand Drive), Four-Wheel Drive (Right Hand Drive), Left Hand Drive, Two-Wheel Drive (Left Hand Drive), Two-Wheel Drive (Right Hand Drive)
View related parts
Mercury Mariner Oxygen Exhaust Gas Sensor
Part Number: 5M6Z-9G444-A
$49.04 MSRP: $79.45
You Save: $30.41 (39%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen
- Replaces: 1R3Z-9G444-DA
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2005-2008 Mercury Mariner | 4 Cyl 2.3L Hybrid Gas/Electric DOHC | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Oxygen Exhaust Gas Sensor
Part Number: 5F9Z-9G444-BA
$58.47 MSRP: $94.73
You Save: $36.26 (39%)
Ships in 1 Business Day
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen
- Manufacturer Note: Rear
- Replaced by: GU2Z-9G444-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2007-2008 Mercury Mariner | 4 Cyl 2.3L | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Oxygen Exhaust Gas Sensor
Part Number: 5L8Z-9G444-J
$59.44 MSRP: $96.29
You Save: $36.85 (39%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen
- Position: Front
- Replaced by: 5L8Z-9G444-F
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2008 Mercury Mariner | 6 Cyl 3.0L DOHC EFI Modular | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Oxygen Exhaust Gas Sensor
Part Number: 5L8Z-9G444-H
$59.44 MSRP: $96.29
You Save: $36.85 (39%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen
- Manufacturer Note: Rear
- Position: Front
- Replaced by: 5L8Z-9G444-F
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2007 Mercury Mariner | 6 Cyl 3.0L DOHC EFI Modular | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Oxygen Exhaust Gas Sensor
Part Number: 5L8Z-9G444-G
$59.94 MSRP: $97.09
You Save: $37.15 (39%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen
- Manufacturer Note: Rear
- Replaced by: 5L8Z-9G444-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2007-2008 Mercury Mariner | 6 Cyl 3.0L DOHC EFI Modular | 4AT CD4E, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Oxygen Exhaust Gas Sensor
Part Number: 1R3Z-9G444-DA
$49.04 MSRP: $79.45
You Save: $30.41 (39%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Sensor - Exhaust Gas - Oxygen
- Replaced by: 5M6Z-9G444-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2005 Mercury Mariner | 4 Cyl 2.3L Hybrid Gas/Electric DOHC | CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Sensor - Hego
Part Number: 9E5Z-9F472-E
$112.95 MSRP: $180.15
You Save: $67.20 (38%)
Product Specifications
- Other Name: Oxygen Sensor, Upper Oxygen Sensor
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2010-2011 Mercury Mariner | 4 Cyl 2.5L Duratec (110kW/150PS) | 6-Speed Automatic Transmission 6F Mid-Range, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive

| Page 1 of 2 |Next >

1-20 of 21 Results

Mercury Mariner Oxygen Sensor

A Mercury Mariner vehicle employs an Oxygen Sensor as part of its emission control system to detect unburned oxygen during engine exhaust which feeds information to the engine control computer. The Mercury Oxygen Sensor computer receives feedback through this mechanism that enables it to regulate the air/fuel mixture for top catalytic converter performance and minimal emission output. A voltage signal emerges from the sensors which reports both lean and rich mixture status to implement precise control through closed-loop systems. Every Mariner vehicle uses multiple Oxygen Sensor units that get installed both before the catalytic converter as upstream measurements and after the converter for determining its operational efficiency. The majority of traditional boats utilize zirconium dioxide sensors yet certain newer models may implement wideband air/fuel ratio Mercury Mariner Oxygen Sensor to deliver improved accuracy through the enlarged measurement capabilities. Periodic sensor aging contributes to performance reduction and emissions control problems in addition to contamination issues.

We provide a wide range of Mercury Mariner Oxygen Sensor at the optimal prices. If you need Mercury Mariner Oxygen Sensor, you can shop with confidence on our website. All our OEM parts come with a manufacturer's warranty and are delivered to your doorstep with a fast delivery service.

Mercury Mariner Oxygen Sensor Parts Questions & Experts Answers

Lower Oxygen Sensor
BE5Z-9G444-A
Q:
What is the general information about Oxygen Sensor and their role on Mercury Mariner?
Posted by Tinashe C.
A:
An oxygen sensor functions as a galvanic battery that generates a small voltage output based on the oxygen levels in exhaust gases, providing essential input for the feedback loop with the Powertrain Control Module (PCM) to maintain the ideal air/fuel ratio of 14.7:1 for optimal catalyst performance. Vehicles equipped with On-Board Diagnostics II (OBD-II) utilize two Oxygen Sensor-one before and one after the Catalytic Converter-to assess converter efficiency by comparing oxygen levels in the exhaust gases. Four-cylinder models feature one upstream and one downstream heated oxygen sensor, while V6 models have four heated sensors, with two for each cylinder head and multiple catalysts. All sensors are heated to reduce warm-up time, and care must be taken during servicing to avoid damaging the permanently attached pigtail and electrical connector, as well as to keep contaminants away from the sensor. When replacing an oxygen sensor, it is advisable to warm the engine to ease removal, apply anti-seize compound to the threads if reusing an old sensor, and ensure proper torque during installation. After reconnecting the battery, the PCM must relearn its idle and fuel trim strategy for optimal performance.
Answered by Ford Parts Specialist George / Sep 23, 2025

Related Mercury Mariner Parts

Browse by Year

2011 Oxygen Sensor 2010 Oxygen Sensor 2009 Oxygen Sensor 2008 Oxygen Sensor 2007 Oxygen Sensor 2006 Oxygen Sensor 2005 Oxygen Sensor