Description
Part Description
This engine control module (ECM) was removed from a 2004 Chevrolet Trailblazer equipped with a 2.7L 4-cylinder engine and automatic transmission. The electronic control unit has been thoroughly inspected by our technicians and is currently on the shelf ready to ship. This OEM part carries the automatic transmission ID numbers 12573576 and 12574976.
The engine control module is the brain of your vehicle’s engine management system, controlling fuel injection, ignition timing, emissions systems, and transmission operation. ECMs commonly fail due to electrical surges, water damage, or internal component degradation over time. When your ECM fails, you may experience no-start conditions, poor fuel economy, transmission shifting problems, or various engine performance issues.
603 Auto Salvage maintains over 50,000 quality used parts in stock from more than 1,100 vehicles. Our experienced team can help you find the exact ECM you need and verify compatibility with your specific vehicle. Call us today or browse our extensive online inventory to get your vehicle back on the road. 50,000+ parts in stock from over 1,100 vehicles. Contact us or call (603) 392-7313 for anything you need.
Part Specifications
| Part | Engine Control Module (ECM) – Electronic Control Unit |
| Interchange # | 7122 |
| OEM Part Number | Contact for OEM# |
| Side | N/A |
| Part Grade | X — Good working condition, inspected and ready to ship. Includes automatic transmission ID numbers 12573576 and 12574976 |
| Warranty | 90-Day Warranty (Standard warranty for electronic control modules) |
| Type | Used OEM |
Vehicle Information (Donor)
| Year / Make / Model | 2004 CHEVROLET TRLBLZ |
| VIN | N/A |
| Vehicle Stock # | PCM3576 |
Our Testing & Inspection Process
Every part at 603 Auto Salvage is inspected before listing. Here is what was verified on this Engine Control Module (ECM) – Electronic Control Unit:
| ✅ Electrical Connections | All connector pins clean and undamaged |
| ✅ Housing Integrity | Case free from cracks or water damage |
| ✅ Circuit Board | Internal components visually inspected |
| ✅ Programming Status | Module ready for reprogramming to your vehicle |
| ✅ Part Numbers | Verified transmission ID numbers match description |
Compatibility — What Vehicles Does This Part Fit?
Based on interchange #7122, this part fits the following vehicles. Always confirm fitment with your mechanic before purchasing.
| Year(s) | Make | Model | Notes |
|---|---|---|---|
| 2004 | Chevrolet | Trailblazer | 2.7L 4-cylinder engine with automatic transmission – Contact us for full compatibility verification |
Questions? Need a shipping quote? Call us now:
603 Auto Salvage | 233 Main St, Plaistow, NH 03865
Mon–Fri 8am–4:30pm | Sat 8am–2pm | Sun Closed
Warranty & Shipping
Frequently Asked Questions
Will this ECM work in my 2004 Chevrolet Trailblazer?
This ECM is compatible with 2004 Trailblazers equipped with the 2.7L 4-cylinder engine and automatic transmission. The module will need to be programmed to your specific vehicle by a qualified technician or dealership.
Does the ECM need to be programmed after installation?
Yes, this engine control module will require programming to match your vehicle’s VIN and security system. This service is typically available at Chevrolet dealerships or qualified automotive shops with the proper diagnostic equipment.
What are the symptoms of a bad ECM?
Common symptoms include engine not starting, poor fuel economy, transmission shifting problems, check engine light, rough idle, or complete loss of engine power. A professional diagnostic scan can help confirm ECM failure.
How do I know if this is the right part number for my vehicle?
Check your existing ECM for part numbers or contact us with your VIN for verification. We can cross-reference the interchange number 7122 to confirm compatibility with your specific Trailblazer.
What transmission types does this ECM support?
This ECM is designed for automatic transmissions with ID numbers 12573576 and 12574976. It will not work with manual transmission vehicles or different automatic transmission variants.
Related Parts & Resources
OEM Part Numbers & Cross-Reference
Looking for this part by number? Here are the reference numbers:
| Interchange Number | 7122 |
| Auto Trans ID | 12573576, 12574976 |
| Engine Type | 2.7L 4-cylinder |
| Stock Number | PCM3576 |
Price Comparison — Why Used OEM Makes Sense
| Source | Price Range | Warranty | Notes |
|---|---|---|---|
| Dealer (New OEM) | $400-600 | 1 year | Brand new, longest wait time |
| Aftermarket | $250-400 | Varies | Non-OEM fitment, quality varies |
| Other Salvage Yards | $150-250 | 30–60 days | Varies in quality and testing |
| 603 Auto Salvage | $100 | 90-Day Warranty | Tested, Grade X, ships in 24hrs |
Installation Notes
- Disconnect battery before removing old ECM to prevent electrical damage
- Take photos of wiring connections before disconnection for reference
- Handle the ECM carefully and avoid static electricity discharge
- Ensure all connections are clean and properly seated before starting vehicle
- Have the new ECM programmed immediately after installation for proper operation
🔍 Free Fitment Check
Call us with your VIN and we will verify compatibility for free. No obligation, no pressure — just answers.
Our parts specialists check interchange data in real-time
Estimated Shipping Costs by Region
This part ships via FedEx Ground. Prices are estimates — call for an exact quote to your zip code.
| Region | Estimated Cost | Transit Time |
|---|---|---|
| New England (NH, MA, ME, VT, CT, RI) | $15 – $30 | 1–3 business days |
| Northeast (NY, NJ, PA, MD, VA) | $20 – $40 | 2–4 business days |
| Southeast (FL, GA, NC, SC, TN) | $25 – $45 | 3–5 business days |
| Midwest (OH, MI, IL, IN, WI, MN) | $30 – $50 | 3–5 business days |
| Southwest (TX, AZ, NM, OK) | $35 – $55 | 4–6 business days |
| West Coast (CA, OR, WA) | $40 – $65 | 5–7 business days |
Local pickup is always free. Free delivery within 30 miles of Plaistow, NH.
Why Buy From 603 Auto Salvage?
- 50,000+ parts in stock from over 1,100 vehicles on-site in Plaistow, NH
- Every part inspected before listing — no guesswork
- Family-owned salvage yard — real people, not a call center
- 90-Day Warranty on this part
- Fast shipping — most orders ship within 24 hours
- Competitive pricing — save 50–70% vs dealer prices
- Serving New Hampshire, Massachusetts & all 50 states
Ready to order? Call (603) 392-7313 or add to cart above. We are here to help.




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