89661-07221 ECU & Programmed Master Key for Toyota Avalon | OEM Denso Blog Detail

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89661-07221 ECU & Programmed Master Key for Toyota Avalon | OEM Denso


Check out our replacement OEM ECU with included programmed master key!

Compatible: 1999 Toyota Avalon

OEM Part Number: 89661-07221 | 8966107221 | TN175200-3680 | TN1752003680

(See description for more details)

SKU WKUS-W-26020|89661-07221 Categories ,


Compatible: 1999 Toyota Avalon

OEM Part Number: 89661-07221 | 8966107221 | TN175200-3680 | TN1752003680

Looking for a plug and play replacement 89661-07221 ECU? 

Want to avoid costly dealer only replacements that cost a fortune? 

We can help! 

This engine control unit (ECU) will include a new, 4C transponder master key that has been programmed to the computer’s immobilizer system.

No additional programming required!

Simply purchase the unit by clicking the Buy Now button above, you will receive an ECU with programmed master key within 4- 8 business days.


The key we provide will need to be cut by a local locksmith or dealer, this can be done for around $40 using your VIN. (We do not cut keys.)

Our tested, pre-owned OEM units include a hassle free 2-year warranty.

Free shipping is included with a package tracking number.

The key shown in the photos is the exact key you will receive.

Part numbers are important, be sure to order a replacement that matches your original part number.

We do not require your VIN. These units do not have VIN programming, only the key data is programmed to the ECUs within these years.

If you need a unit and are outside the United States, please reach out to us via email with your address for a shipping quote.

We do not offer Express shipping at this time.

Supplies may be limited.

Technician’s Notes: 

In many modern vehicles, components are equipped with a theft deterrent called an immobilizer system.

The Toyota Avalon was equipped with an immobilizer system starting with its second generation model in 1999.

If the key doesn’t match with the ECU – the immobilizer system will not allow your vehicle to start.

Each key we program to the unit is unique. Your original keys will no longer work with this unit, only the key we provide will start the vehicle.

If you plan on replacing your ECU – our programmed key/ECU combo is the perfect solution.

Some common symptoms of a bad ECU include:

  • Rough idle
  • Cylinder misfire
  • Poor acceleration
  • Not found via OBD
  • A/C no longer functions
  • Failure or difficult to start
  • Fault codes that will not clear
  • Transmission shifting problems

Included Key Specs

  • Condition: New
  • Key Type: TOY43
  • Transponder: 4C
  • Program Type: Master Key

Other acronyms for the Engine Computer: ECU Engine Control Unit – ECM Engine Control Module – BCM Body Control Module – PCM Power Control Module

We understand for some, a vehicle is part of the family. Our mission is to get your vehicle back on the road by offering quick and cost-effective solutions.

If you have any questions about this unit or anything else, please do not hesitate to reach out to us!

-Module Mechanics
  • Condition: NEW

Additional information







Part Number


Part Numbers

8966107221, TN175200-3680, TN1752003680


Our mission is providing unique and cost saving solutions to combat the automotive industries problematic electronic issues, keeping you in your car, not your wallet. 

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Module Mechanics

6732 W. Coal Mine Ave, STE 511, Littleton, CO 80123

*Please include your name or order number with the shipment

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