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Mass Air Flow Sensor
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Mass Air Flow Sensor (Walker Products) for 1999-2010 Audi, BMW, Land Rover, & Mercedes-Benz NEW

$ 83 .72
120-DayReturns
LifetimeWarranty
100%Money-Back

Product Notes Read before buying

Sensor Only
Walker Products MAF sensors are always 100% NEW and NEVER remanufactured! All sensors are 100% programmed and tested for fit, form, and function before being available to be sold. As an industry leading program, Walker Products manufacturers high demand SKUs in our USA facilities with OEM quality components, custom engineered circuit boards, and programing. Many of the Walker MAF parts are designed and built here in the USA at Walker Products facilities. The Walker Mass Air Flow Sensor program offers replacement sensors in both Sensor Only and Complete Sensor and Housing Assemblies. Sensor only replacement is typically faster and more economical, but some manufacturers recommend that you replace the complete housing assembly to ensure the connector air tubes are clean and to protect the sensor itself, which can be damaged by oils on your hands or even air pollution. Walker Products Mass Airflow Sensors stand apart from the competition due to the focus on ensuring customers receive the best product possible. The most popular applications are made entirely in the United States which allows for the highest quality sensors. When it comes to MAFs, it is vital that they are properly tuned to the vehicle, which is why Walker’s team of engineers work to create sensors that have custom tuned flow characteristics for the full flow spectrum. Walker MAFs continue to meet or exceed OE long-term fuel trim percentages, and calibrations go through 100% production testing and are always verified using on vehicle testing. Walker Products provides our customers with the confidence that they are investing in nothing short of the best. Walker Products began supplying the fuel system needs of the automotive industry in 1946. Today, Walker is an ISO 9001/ IATF16949 certified manufacturer, and one of the largest privately owned manufacturers of fuel system components and engine sensors.
Brand: Walker Products
Condition: New
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Specifications & Info


Attribute Value
CA Prop65 Lead Warning: This Product Can Expose You To Chemicals, Including Lead, Which Is Known To The State Of California To Cause Cancer Or Birth Defects Or Other Reproductive Harm. Www.p65warnings.ca.gov
Connector Gender Female
Housing Included No
Mounting Hardware Included Yes
Terminal Quantity 5

Vehicle Fitment Guide

This part fits the following vehicles:

Audi 1 model (tapclick to expand)(tapclick to hide)
A3 1999-2001 (tapclick to expand)(tapclick to hide)
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SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
Ambiente Hatchback 2001 L4 1.8L Turbo FWD Automatic & Manual
Ambition Hatchback 2000 - 2001 L4 1.8L Turbo FWD Automatic & Manual
Attraction Hatchback 2000 - 2001 L4 1.8L Turbo FWD Automatic & Manual
Base Hatchback 1999 L4 1.8L Turbo FWD Automatic & Manual
BMW 5 models (tapclick to expand)(tapclick to hide)
540i 1999-2003 (tapclick to expand)(tapclick to hide)
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SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
Base Sedan 1999 - 2003 V8 4.4L RWD Automatic & Manual
Base Wagon 1999 - 2003 V8 4.4L RWD Automatic & Manual
740i 1999-2001 (tapclick to expand)(tapclick to hide)
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SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
Base Sedan 1999 - 2001 V8 4.4L RWD Automatic
740iL 1999-2001 (tapclick to expand)(tapclick to hide)
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SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
Base Sedan 1999 - 2001 V8 4.4L RWD Automatic
X5 2000-2003 (tapclick to expand)(tapclick to hide)
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SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
3.0i SUV 2001 - 2003 L6 3.0L AWD Automatic & Manual
4.4i SUV 2000 - 2003 V8 4.4L AWD Automatic
4.4i Formula 1 SUV 2003 V8 4.4L AWD Automatic & Manual
4.4i Lujo SUV 2000, 2002 - 2003 V8 4.4L AWD Automatic & Manual
4.4i Top Line SUV 2000, 2002 - 2003 V8 4.4L AWD Automatic & Manual
4.6is SUV 2002 - 2003 V8 4.6L AWD Automatic
Z8 2003 (tapclick to expand)(tapclick to hide)
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SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
Alpina Convertible 2003 V8 4.8L RWD Automatic
Base Convertible 2003 V8 4.9L RWD Manual
Base Convertible 2003 V8 5.0L RWD Manual
Land Rover 1 model (tapclick to expand)(tapclick to hide)
Range Rover 2003-2004 (tapclick to expand)(tapclick to hide)
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SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
Base SUV 2003 - 2004 V8 4.4L AWD Automatic
HSE SUV 2003 - 2004 V8 4.4L 4WD Automatic
Mercedes-Benz 3 models (tapclick to expand)(tapclick to hide)
G55 AMG 2010 (tapclick to expand)(tapclick to hide)
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SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
Base SUV 2010 V8 5.4L Supercharged AWD Automatic
Base SUV 2010 V8 5.5L Supercharged 4WD Automatic
S55 AMG 2004 (tapclick to expand)(tapclick to hide)
Swipe left/right to see more info
SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
Base Sedan 2004 V8 5.4L Supercharged RWD Automatic
Base Sedan 2004 V8 5.5L Supercharged RWD Automatic
SL55 AMG 2003-2006 (tapclick to expand)(tapclick to hide)
Swipe left/right to see more info
SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
Base Convertible 2004 - 2006 V8 5.5L Supercharged RWD Automatic
Base Convertible 2003 - 2006 V8 5.4L Supercharged RWD Automatic
Kompressor Convertible 2003 V8 5.5L Supercharged RWD Automatic
Verify before ordering — please confirm your vehicle's year, make, model and sub-model specifications before placing your order. If anything is unclear, our customer service team is available to help.

Policies, in plain English.

Shipping Information

We offer fast, reliable shipping on all orders:

  • Ships to all countries via US Postal Service Priority Mail.
  • Most orders ship within 1 business day.
  • Delivery time: 1-4 business days after shipment.
  • International shipping available, including APO/FPO addresses.
  • Tracking information provided for all shipments.
  • Additional handling fees may apply for oversized/overweight packages.

Lifetime Warranty

This part comes with a limited lifetime warranty. Warranty begins on the original purchase date.

Warranty does NOT cover:

  • Shipping costs or labor expenses.
  • Installation errors.
  • Parts used for racing.
  • Commercial vehicle parts.

Returns (120 Days)

We want you to be 100% satisfied with your purchase. That's why we offer:

  • 120-Day Returns - Return any part within 120 days from date of receipt.
  • Must obtain RMA (Return Merchandise Authorization) number before returning.
  • Parts must be in original condition, uninstalled, unaltered, and in original packaging.
  • Important: Electrical parts are not returnable if unsealed.
  • Please inspect parts upon arrival and notify us within 5 days of receiving incorrect or damaged parts.
  • Refunds processed after warehouse receives return and credited to original payment method.
Walker Products MAF sensors are always 100% NEW and NEVER remanufactured! All sensors are 100% programmed and tested for fit, form, and function before being available to be sold. As an industry leading program, Walker Products manufacturers high demand SKUs in our USA facilities with OEM quality components, custom engineered circuit boards, and programing. Many of the Walker MAF parts are designed and built here in the USA at Walker Products facilities. The Walker Mass Air Flow Sensor program offers replacement sensors in both Sensor Only and Complete Sensor and Housing Assemblies. Sensor only replacement is typically faster and more economical, but some manufacturers recommend that you replace the complete housing assembly to ensure the connector air tubes are clean and to protect the sensor itself, which can be damaged by oils on your hands or even air pollution. Walker Products Mass Airflow Sensors stand apart from the competition due to the focus on ensuring customers receive the best product possible. The most popular applications are made entirely in the United States which allows for the highest quality sensors. When it comes to MAFs, it is vital that they are properly tuned to the vehicle, which is why Walker’s team of engineers work to create sensors that have custom tuned flow characteristics for the full flow spectrum. Walker MAFs continue to meet or exceed OE long-term fuel trim percentages, and calibrations go through 100% production testing and are always verified using on vehicle testing. Walker Products provides our customers with the confidence that they are investing in nothing short of the best. Walker Products began supplying the fuel system needs of the automotive industry in 1946. Today, Walker is an ISO 9001/ IATF16949 certified manufacturer, and one of the largest privately owned manufacturers of fuel system components and engine sensors.

Interchange Parts

Brand Part Number
Blue Streak MF21157N

Fits Years: 1999 2000 2001 2002 2003 2004 2005 2006 2010

Fits Models: 540i, 740i, 740iL, A3, G55 AMG, Range Rover, S55 AMG, SL55 AMG, X5, Z8

Expert Guide

Audi A3 1998-2005 Mass Air Flow Sensor Replacement Guide

Fix rough idling and poor acceleration by understanding your A3's Mass Air Flow (MAF) sensor.

 Read Full Guide →
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120
Day Return Window

4× the Industry Standard

Most retailers stop at 30 days. We give you a full four months to install, test, and return for a 100% refund — return shipping on us.

NEW
Direct-Fit Replacement

Engineered To OEM Specs

Brand-new aftermarket parts from trusted suppliers — built to original-equipment specifications so they fit and function like the factory unit, at a fraction of the price.

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