Restore Peak Performance to Your Cadillac XLR
Is your 2009 Cadillac XLR suffering from frustrating issues like intermittent stalling, a persistent check engine light, or a complete no-start condition? The Engine Control Module (ECM), often called the engine’s brain, is the central command unit responsible for managing everything from fuel injection and ignition timing to transmission shifting and emissions control. When it fails, it can cause a wide range of perplexing and performance-robbing symptoms. This genuine GM Engine Control Module, part number 12639300, is the definitive solution to get your vehicle back on the road and running like new.
Is Your Cadillac XLR Showing Signs of ECM Failure?
A failing ECM can be difficult to diagnose, as its symptoms often mimic other component failures. If you’re experiencing any of the following, a faulty engine computer could be the culprit. This is especially true if you’ve already replaced sensors or other parts without success. Pay close attention if your vehicle exhibits several of these issues.
- ✔ Check Engine Light: An illuminated check engine light is the most common sign. You may find communication-related diagnostic trouble codes (DTCs), such as U-codes, or codes for multiple, unrelated sensors.
- ✔ Engine Performance Problems: Noticeable loss of power, poor acceleration, rough idling, or engine misfires can all point to a computer that is not correctly managing the engine’s operations.
- ✔ Intermittent Stalling: The engine may stall for no apparent reason, either while driving or at a stop. This can be a dangerous symptom that should be addressed immediately.
- ✔ No-Start Condition: You might find that the engine cranks over but refuses to start. This can happen if the ECM is not properly controlling the fuel pump or ignition system.
- ✔ Poor Fuel Economy: A sudden and unexplained drop in your vehicle’s gas mileage can occur when the ECM fails to calculate the optimal air-fuel mixture.
- ✔ Transmission Shifting Issues: The ECM works in tandem with the transmission control module. A faulty ECM can lead to harsh shifting, delayed engagement, or the transmission getting stuck in one gear.
From the Diagnostic Bay
We had a 2009 Cadillac STS (which uses a similar ECM) come into the shop with an issue that had stumped two other mechanics. The car would run perfectly for 20-30 minutes, then suddenly stall and refuse to restart for an hour. There were no consistent trouble codes, just a random collection of sensor faults that changed each time. After checking wiring and grounds, we suspected the ECM was failing under heat. We connected a scan tool to monitor live data and saw the fuel injector pulse width data go haywire just before it stalled. Swapping in a pre-programmed ECM like this one solved the problem instantly. The customer was thrilled to have their car back and running reliably after weeks of uncertainty.
The Direct-Fit Solution: A Programmed 2009 XLR Engine Module
Don’t let a faulty computer keep your luxury vehicle sidelined. This isn’t just a replacement part; it’s a complete, ready-to-install solution. The biggest hurdle when replacing a modern ECM is the need for expensive, dealer-specific programming. We eliminate that step entirely. When you order from us, we use your vehicle’s Vehicle Identification Number (VIN) to flash this module with the latest, most stable software updates directly from General Motors. This ensures perfect compatibility and can even resolve underlying drivability issues that were present in the original factory software.
Your new 2009 XLR Engine Module will arrive at your door ready for installation. In most cases, the only post-installation step is a simple security relearn procedure, which you can perform yourself in your driveway without any special tools. This procedure syncs the new ECM with your vehicle’s anti-theft system and typically involves a series of key-on/key-off cycles. We provide clear instructions to make this process straightforward.
Guaranteed Compatibility
This ECM, identified by service number 12639300, is a direct replacement for a wide range of original part numbers, ensuring broad compatibility across numerous GM vehicles. If your original module has any of the following numbers, this unit is the correct replacement: 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, or 12678512. Beyond the 2009 XLR Engine Module, this part also fits vehicles such as:
- 2009-2011 Cadillac DTS & Lucerne (4.6L)
- 2009 Cadillac STS (4.4L, 4.6L) & SRX (4.6L)
- 2009 Cadillac CTS (6.2L) & Corvette (ZR1)
- 2009-2012 Chevrolet Colorado & GMC Canyon (2.9L, 3.7L)
- 2009 Chevrolet Trailblazer (6.0L) & GMC Envoy (5.3L)
- 2009-2010 Hummer H3 (3.7L)
- 2009 Saab 9-7x
Frequently Asked Questions
Do I need to take this part to a dealer for programming?
No. This is the primary benefit of our service. We program the module to your specific VIN before we ship it. It arrives ready for installation, saving you time and the high cost of dealer programming.
What is the security relearn procedure?
It’s a simple procedure that syncs the new ECM to your vehicle’s anti-theft system. It typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating this cycle three times. We include detailed instructions for your vehicle.
Why do you need my VIN?
Your VIN is essential. It allows us to access the exact GM-certified software, calibrations, and updates specific to your vehicle’s engine, transmission, and options. This guarantees a perfect match and optimal performance.
Where is the ECM located on my 2009 Cadillac XLR?
On the 2009 XLR, the Engine Control Module is typically located in the right-hand (passenger side) front of the engine compartment. Always disconnect the battery before attempting removal or installation.
Is this a used part?
This is a high-quality, genuine GM original equipment part that has been thoroughly inspected and tested to ensure it meets or exceeds factory specifications. It is not a new part, but a reliable and proven component.