Restore Peak Performance to Your Cadillac
Is your 2009-2010 Cadillac STS running rough, stalling unexpectedly, or refusing to start? A failing Engine Control Module (ECM) is often the culprit. As the ‘brain’ of your vehicle’s engine, the ECM governs everything from fuel mixture and ignition timing to transmission shifting. When it falters, you experience a cascade of frustrating and potentially damaging problems. This isn’t just an inconvenience; it’s a critical component failure that needs a reliable solution.
This direct-fit Engine Control Module, part number 12628993, is the definitive fix. Forget about expensive dealership visits and the hassle of towing your vehicle for programming. We handle the critical first step for you. Simply provide your vehicle’s VIN during checkout, and our technicians will flash the module with the latest, most stable GM software updates specific to your car. It arrives at your door ready for installation, saving you time, money, and headaches.
Case Study: A Tricky Diagnosis
I once had a 2009 Cadillac CTS in the bay with a ghost of a problem. The owner complained of intermittent stalling at stoplights and a weird hesitation under light acceleration—but no consistent check engine light. We checked fuel pressure, scanned for codes (nothing stored), and inspected for vacuum leaks. Everything seemed fine. On a hunch, I monitored live data from the ECM and noticed the short-term fuel trim values would suddenly spike just before a stall. After ruling everything else out, we swapped in a known-good ECM. The problem vanished instantly. The original module had an internal fault that only appeared under specific thermal conditions, a classic sign of ECM failure that scan tools can sometimes miss.
Is Your Vehicle Showing These Symptoms?
A failing ECM can manifest in numerous ways. If you’re experiencing any of the following, it’s a strong indicator that your engine’s computer needs attention:
- ✔ Check Engine Light is on with codes like P0601, P0606, or other internal processor faults.
- ✔ Vehicle has difficulty starting or won’t start at all.
- ✔ Noticeable decrease in fuel economy.
- ✔ Engine stalling, stuttering, or misfiring.
- ✔ Poor or erratic automatic transmission shifting.
- ✔ Communication errors with diagnostic scan tools.
Your Straightforward Installation Guide
Installing your new 2009-2010 STS ECM is a manageable job for a confident DIYer. Follow these steps carefully for a successful replacement.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 15 minutes for the system capacitors to discharge.
- Locate the ECM: On the 2009-2010 Cadillac STS, the ECM is typically located on the left-hand (driver’s side) frame rail. Consult a service manual for your specific vehicle if you are unsure.
- Disconnect Connectors: Carefully release the locking tabs on the electrical wiring harnesses and gently pull them straight out from the module. Never force them. Inspect the connectors for any corrosion or damaged pins.
- Remove the Old Module: Unbolt the mounting hardware that secures the old ECM to its bracket or the vehicle frame. Remove the old unit.
- Install the New Module: Mount your new, pre-programmed ECM in place and secure it with the original hardware.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new ECM until they click into place. Reconnect the negative battery terminal.
- Final Steps: Some vehicles may require a security relearn or crank position sensor relearn procedure, which can often be initiated without special tools. Check your vehicle’s service information for specific instructions. Start the engine and check for proper operation.
Will This Fit My Vehicle?
This module is a direct replacement for a wide range of GM vehicles and is interchangeable with service numbers 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512. Please verify fitment for your specific model and engine below:
CADILLAC DTS 09-11
CADILLAC SRX 09 (4.6L)
CADILLAC STS 09 (4.4L, 4.6L)
CADILLAC STS 10 (4.6L)
CADILLAC XLR 09
CHEVROLET COLORADO 09-12 (2.9L, 3.7L)
CHEVROLET CORVETTE 09 (ZR1)
CHEVROLET TRAILBLAZER 09 (6.0L)
GMC CANYON 09-12 (2.9L, 3.7L)
GMC ENVOY 09 (5.3L)
HUMMER H3 09-10 (3.7L)
BUICK LUCERNE 09-11 (4.6L)
SAAB 9-7X 09
Frequently Asked Questions
Do I need to do any programming myself?
No. This 2009-2010 STS ECM arrives pre-programmed to the VIN you provide at checkout. It is ready for installation right out of the box, though some vehicles may require a simple key relearn procedure.
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to load the exact GM-certified software for your car’s specific options, engine, and transmission. This ensures perfect compatibility and performance.
Is this compatible with other part numbers?
Yes, this module is a direct replacement for several service numbers, including 12636659, 12628993, 12625453, and more as listed in the description. This ensures you are getting the correct, updated part.
What if my original part number isn’t on the list?
Please contact us with your VIN and original part number before ordering. We can verify compatibility to ensure you receive the correct module for your vehicle.