Restore Peak Performance to Your Vehicle’s Powertrain
Is your 2004-2005 Cadillac CTS V-Series or another compatible GM vehicle suffering from frustrating engine problems? An illuminated Check Engine Light, unexplained stalling, poor fuel economy, or erratic transmission shifting are often signs that the brain of your engine—the Powertrain Control Module (PCM)—is failing. In my 20+ years of hands-on diagnostics, I’ve seen how a faulty PCM can cause a cascade of issues that are difficult to pin down. This module is the direct solution, restoring the crisp performance and reliability you expect from your vehicle.
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We flash this PCM with the latest official GM software updates, specifically programmed to your vehicle’s unique Vehicle Identification Number (VIN). This critical step ensures seamless communication between all vehicle systems, proper engine function, and correct transmission shifting, eliminating the need for an expensive trip to the dealership for programming. Simply provide your VIN after purchase, and we handle the rest.
From the Diagnostic Bay: The Ghost in the CTS-V
I remember a 2005 Cadillac CTS-V that came into my shop with a list of phantom problems. The owner was frustrated; he’d been to two other places. The car would run perfectly for days, then suddenly stall at a stoplight or refuse to start. It threw random communication codes that would disappear on their own. We checked wiring, sensors, and grounds—everything seemed fine. On a hunch, based on seeing similar heat-related failures, we monitored the PCM’s internal data stream. As the engine bay warmed up, the processor started dropping data packets. The original PCM had a hairline fracture on the circuit board that only became an issue at operating temperature. We installed a VIN-programmed module just like this one, and the car ran flawlessly. It’s a perfect example of how the right part, correctly prepared, is the only real fix.
Common Signs of a Failing PCM
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (PCM Processor Fault).
- ✔ Your vehicle fails to start or stalls intermittently.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ The transmission shifts harshly, late, or not at all.
- ✔ The engine runs rough, misfires, or hesitates on acceleration.
- ✔ Loss of communication with the scan tool or other modules (U-codes).
A Straightforward Guide to Installation
Installing your new 2004-2005 CTS PCM is a manageable job for a confident DIYer. For the Cadillac CTS, the module is typically located in the engine compartment on the right-hand (passenger) side.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait 10-15 minutes for the system to discharge completely.
- Locate the PCM: Identify the Powertrain Control Module. It’s a metal box with large electrical connectors.
- Disconnect Connectors: Carefully unlatch and remove all electrical harnesses connected to the old PCM. Be gentle, as the plastic clips can become brittle over time.
- Remove the Old Module: Unbolt the PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten the bolts.
- Reconnect Everything: Plug the electrical connectors firmly back into the new module until they click into place. Reconnect the negative battery terminal.
- Final Steps: In many cases, the vehicle will start and run perfectly. Some GM vehicles may require a simple security relearn procedure (often called a Passlock or Passkey relearn), which can typically be done without special tools. Instructions are widely available online or in your service manual.
Verified Vehicle Compatibility
This module is a direct replacement for part numbers 12589462, 12602801, and 89017749. It is guaranteed to fit the following vehicles and configurations. Please verify your vehicle is on this list before ordering.
SILVERADO 2500 PICKUP 05-06 Electronic Control Module; (LH front under battery), gasoline, 8.1L
SAVANA 2500 VAN 07 Electronic Control Module; (LH rear engine compartment), gasoline
SILVERADO 1500 PICKUP 07 Electronic Control Module; classic style (creased door skin), (LH front under battery), w/o hybrid option; w/4.3L
EXPRESS 3500 VAN 07 Electronic Control Module; (LH rear engine compartment), gasoline
SUBURBAN 2500 05-06 Electronic Control Module; (LH front under battery), 8.1L
AVALANCHE 2500 05-06 Electronic Control Module; (LH front under battery)
SIERRA 2500 PICKUP 07 Electronic Control Module; classic style (creased door skin), (LH front under battery), gasoline, 8.1L
SILVERADO 3500 PICKUP 05-06 Electronic Control Module; (LH front under battery), gasoline, 8.1L
EXPRESS 2500 VAN 07 Electronic Control Module; (LH rear engine compartment), gasoline
SAVANA 2500 VAN 05 Electronic Control Module; (LH rear engine compartment)
SAVANA 3500 VAN 05 Electronic Control Module; (LH rear engine compartment)
BLAZER S10/JIMMY S15 05 Electronic Control Module; (RH front engine compartment)
CTS 04-05 Electronic Control Module; (RH engine compartment), V-Series, ID 12589462
EXPRESS 2500 VAN 06 Electronic Control Module; gasoline, (LH rear engine compartment)
SAVANA 1500 VAN 05-07 Electronic Control Module; (LH rear engine compartment)
EXPRESS 2500 VAN 05 Electronic Control Module; (LH rear engine compartment)
EXPRESS 3500 VAN 05 Electronic Control Module; (LH rear engine compartment)
SAVANA 2500 VAN 06 Electronic Control Module; gasoline, (LH rear engine compartment)
SIERRA 3500 PICKUP 05-06 Electronic Control Module; (LH front under battery), gasoline, 8.1L
SILVERADO 3500 PICKUP 07 Electronic Control Module; classic style (creased door skin), (LH front under battery), gasoline, 8.1L
SAVANA 3500 VAN 06 Electronic Control Module; gasoline, (LH rear engine compartment)
SIERRA 2500 PICKUP 05-06 Electronic Control Module; (LH front under battery), gasoline, 8.1L
SAVANA 3500 VAN 07 Electronic Control Module; (LH rear engine compartment), gasoline
SIERRA 1500 PICKUP 05-06 Electronic Control Module; (LH front under battery), w/o hybrid option; w/4.3L
SIERRA 1500 PICKUP 07 Electronic Control Module; classic style (creased door skin), (LH front under battery), w/o hybrid option; w/4.3L
SIERRA 3500 PICKUP 07 Electronic Control Module; classic style (creased door skin), (LH front under battery), gasoline, 8.1L
ASTRO 05 Electronic Control Module; (LH front by battery)
EXPRESS 1500 VAN 05-07 Electronic Control Module; (LH rear engine compartment)
EXPRESS 3500 VAN 06 Electronic Control Module; gasoline, (LH rear engine compartment)
SILVERADO 1500 PICKUP 05-06 Electronic Control Module; (LH front under battery), w/o hybrid option; w/4.3L
YUKON XL 2500 05-06 Electronic Control Module; (LH front under battery), 8.1L
CTS 05 Electronic Control Module; (RH engine compartment), V-Series, ID 12602801
SILVERADO 2500 PICKUP 07 Electronic Control Module; classic style (creased door skin), (LH front under battery), gasoline, 8.1L
Why do you need my VIN?
Why do you need my VIN?
Your VIN (Vehicle Identification Number) allows us to program the PCM with the exact software and calibrations your specific vehicle requires. This ensures perfect compatibility with your engine, transmission, and options package, making the installation process plug-and-play.
Will I need to do anything after installing it?
After installation, some GM vehicles require a security relearn procedure to sync the new PCM with the anti-theft system. This is a simple process that typically involves turning the key in the ignition in a specific sequence. It does not require a scan tool and instructions are readily available online.
Is this compatible with other part numbers?
Yes, this module is a direct replacement for service numbers 12589462, 12602801, and 89017749. If your original module has one of these numbers, this part is a guaranteed fit.
How do I find my original part number?
The part number is printed on a sticker on the case of your current PCM. You will need to locate the module on your vehicle to read it directly.