If you’re dealing with baffling engine problems in your 2006 Cadillac STS, the root cause is often the very component that’s supposed to be in charge: the Engine Control Module (ECM). As a technician with over two decades of experience, I’ve seen countless drivers chase expensive sensor replacements and wiring repairs, only to find the ECM itself was the culprit. This isn’t just a part; it’s the central computer for your engine, and when it fails, it can cause everything from a simple check engine light to a frustrating no-start condition.
We offer a dependable and straightforward solution. This ECM, part number 12590032, is a direct-fit replacement that comes professionally programmed to your vehicle’s specific Vehicle Identification Number (VIN). We load it with the latest official GM software updates before it even leaves our facility. This critical step ensures optimal performance, fuel efficiency, and resolves many underlying issues that older software versions may have had. You get a part that is truly ready to install right out of the box, saving you from a costly trip to the dealership for programming.
A Technician’s Notebook
I remember a 2006 Cadillac STS with the 4.4L V8 that came into the shop with a complaint of intermittent stalling at stoplights and a check engine light that would come and go. The owner had already replaced the crankshaft position sensor and a throttle body with no luck. A scan showed a P0601 (Internal Control Module Memory Check Sum Error) and a U0100 (Lost Communication With ECM). These codes, especially together, are a classic sign of internal ECM failure. The module’s processor was failing intermittently under heat soak. We installed one of our pre-programmed ECMs, performed the security relearn, and the car ran perfectly. It’s a textbook case where targeting the ‘brain’ first saves time, money, and a lot of headaches.
Is Your Cadillac Exhibiting These Symptoms?
A failing ECM can manifest in numerous ways. If you’re experiencing any of the following, this module is the likely solution:
- âś” Check Engine Light is on with no clear cause
- âś” Engine cranks but refuses to start
- âś” Unexplained drop in fuel economy
- âś” Rough idling, stalling, or hesitation during acceleration
- âś” Harsh or erratic automatic transmission shifting
- âś” Communication error codes, such as U0100 or other U-codes
- âś” Internal module failure codes like P0601, P0603, or P0606
A Straightforward Guide to Installation
Installing your new 2006 STS Engine Control Module is a manageable job for a confident DIYer. While specific steps may vary slightly by exact model, the general process is consistent.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the ECM: On the 2006 STS, the ECM is typically found mounted on the left-hand (driver’s side) frame rail in the engine compartment.
- Disconnect Connectors: Carefully release the locking tabs on the electrical wiring harnesses and unplug them from the old module. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Bolt your new, pre-programmed ECM into place.
- Reconnect Everything: Securely plug the wiring harnesses back into the new module. You should hear a ‘click’ as they lock. Reconnect the negative battery terminal.
- Perform Security Relearn: You will likely need to perform a simple key-cycle security relearn procedure to sync the new ECM with your vehicle’s anti-theft system. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine.
Verified Vehicle Compatibility
This ECM is a direct replacement for service number 12590032 and is also interchangeable with numbers 12602044, 12603530, 12605843, 12607096, 12630457, and 19210737. It fits a wide range of GM, Saab, and Isuzu vehicles. Please verify your specific model and options below:
Frequently Asked Questions
How do I provide my VIN for programming?
After you complete your purchase, simply send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot ship your module until we receive this information, as the programming is essential for it to function in your car.
Is any additional programming required after installation?
No. This 2006 STS Engine Control Module arrives pre-programmed with the latest GM software matched to your VIN. The only step you may need to perform is a simple ‘Security Relearn’ procedure, which takes about 30 minutes and requires only your car key.
My original ECM has a different part number. Will this still work?
Yes, as long as your original part number is one of the interchangeable service numbers listed (e.g., 12602044, 12603530, etc.). This module is the correct hardware platform for a wide variety of GM vehicles from this era.
What if I don’t program the module?
The module will not work. The programming links the ECM to your car’s specific systems, including the ignition, fuel injectors, and anti-theft system. An unprogrammed module will result in a no-start condition.