2006-2007 Scion tC ECM: Failure Symptoms, Part Numbers, and Programming Guide
This guide covers common symptoms, critical part number details, and the necessary immobilizer reprogramming for the 2006-2007 Scion tC Engine Control Module.
- Compatibility is critical: This ECM only fits automatic Scion tC models built between May 2006 and March 2007.
- Programming is mandatory: A replacement ECM must be programmed to the car's immobilizer system to recognize your keys.
- A locksmith can often program it: You can frequently avoid a dealership visit by using a qualified automotive locksmith with Toyota/Scion programming tools.
- Match the part number exactly: Ensure the OEM part number on the replacement module matches your original to guarantee compatibility.
Symptoms of a Failing Scion tC ECM
A failing ECM can cause a wide range of issues, from minor annoyances to critical failures that prevent the vehicle from starting. Diagnosing a bad ECM can be tricky, as its symptoms often mimic those of other failing components.
🎬 Watch: 11 common symptoms of a bad ECM- Check Engine Light: An illuminated Check Engine Light is one of the most common signs. A faulty ECM might store trouble codes, with P0606 (Control Module Processor) being a strong indicator of internal failure.
- Engine Performance Issues: You may experience engine stalling, misfiring, rough idling, poor acceleration, or a sudden decrease in fuel economy. These problems occur because the ECM can no longer accurately control the fuel and spark delivery.
- No-Start Condition: A completely failed ECM can prevent the engine from starting at all. The module may not be sending the necessary signals to the ignition system or fuel injectors.
- Transmission Shifting Problems: On automatic transmission models, a bad ECM can send incorrect data to the transmission control module, leading to harsh, erratic, or delayed shifting.
- Random Electrical Glitches: Since the ECM is a central part of the car's electronics, its failure can sometimes cause seemingly unrelated issues with dashboard lights or other electronic components.
Known Issues, TSBs, and Recalls
While the ECM itself is not a common failure point, the 2006-2007 Scion tC was subject to a few recalls and common complaints. No recalls directly target the Engine Control Module for this specific year range. However, owners have reported issues with excessive oil consumption and problems with the VVT-i controller, which could potentially be misdiagnosed as ECM problems. There was also a safety recall for certain 2005-2006 tC models concerning the side and curtain shield airbag sensors, but this is unrelated to the ECM's function.
Compatibility Warning: This specific group of ECMs only fits 2006 Scion tC models manufactured from May 2006 and 2007 Scion tC models manufactured through March 2007. It is exclusively for vehicles with an Automatic Transmission. Always verify your vehicle's production date and transmission type before purchasing a replacement.
Programming and Immobilizer Requirements
A replacement ECM for a 2006-2007 Scion tC must be programmed to the vehicle. The ECM is linked to the car's anti-theft system, known as the immobilizer. The immobilizer prevents the engine from starting unless it recognizes the unique transponder chip inside your car key. When you install a different ECM, it will not recognize your existing keys, and the car will not start.
This process is often called an "immobilizer reset" or "key registration." It involves erasing the old key data from the replacement ECM and programming your existing keys to it. This can typically be done in one of three ways:
- Automotive Locksmith: Many mobile locksmiths have the specialized equipment, such as a Toyota Techstream scan tool, needed to perform an immobilizer reset and program new keys. This is often the most convenient and cost-effective option.
- Toyota/Scion Dealership: A dealership can always perform the necessary programming.
- Mail-In Programming Service: Some companies offer services where you send them your original ECM and the replacement unit. They will clone the immobilizer data from your old module to the new one, making the replacement "plug-and-play" without any additional programming required upon installation. 🎬 Watch: How to reset the immobilizer using a paperclip
Buying a Used Engine Control Module
Purchasing a used OEM ECM is a great way to save money, but careful verification is key. A used original part is often more reliable than a new, cheap aftermarket unit.
- Match Part Numbers Exactly: The most critical step is to match the OEM part number on the replacement ECM with your original. The verified part numbers for this application are 89661-21500, 89661-21520, 89661-21521, and 89661-21480.
- Inspect for Damage: When you receive the used ECM, inspect the case for any signs of physical damage or water intrusion. Check all the connector pins to ensure they are straight and free of corrosion.
- Factor in Programming Costs: Remember that the price of the used module is not the final cost. You must account for the additional expense of having it programmed by a locksmith or dealer.
- Verify the Source: Purchase from a reputable seller that offers a warranty. This protects you in case the module is faulty.
Replacement Cost Comparison
The cost to replace the ECM can vary significantly based on the source of the part and labor rates.
| Part Type | Estimated Cost |
|---|---|
| New OEM | $513 - $547 |
| Remanufactured / Refurbished | $220 - $380 |
| Used OEM | $75 - $150 |
| Shop Labor (including programming) | $100 - $250 |
Frequently Asked Questions (FAQ)
Do I have to go to a Scion/Toyota dealer for programming?
No, you do not necessarily have to go to a dealer. A well-equipped independent auto shop or a certified automotive locksmith can often perform the required immobilizer reset and key programming, sometimes at a lower cost.
What happens if I install a used ECM without programming it?
If you install an unprogrammed ECM, the engine will crank but will not start. The security light on the dashboard may blink, indicating that the immobilizer system is active and does not recognize the key.
Where is the ECM located on a 2006-2007 Scion tC?
The ECM is typically located behind the glove box on the passenger side of the dashboard. Accessing it requires removing the glove box assembly.
🎬 See this step-by-step Scion tC ECU removal guideCan I use an ECM from a manual transmission tC in my automatic?
No. The ECM is specific to the transmission type. An ECM from a manual transmission vehicle will not have the correct software to control an automatic transmission and will cause significant operational problems.
Helpful Videos
Technical Specifications
OEM Part Numbers: 89661-21500 89661-21520 89661-21521 89661-21480
For vehicles with Automatic Transmission only. Fits vehicles with a production date from 05/2006 through 03/2007.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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