Restore Your Cadillac’s Brainpower and Performance

Is your 2005 Cadillac DeVille running rough, stalling unexpectedly, or showing a persistent Check Engine Light? These frustrating issues often point to a failing Engine Control Module (ECM)—the central computer that manages everything from fuel mixture and ignition timing to transmission shifting. A faulty ECM can cripple your vehicle’s performance and reliability. This isn’t just a replacement part; it’s a complete, ready-to-install solution for your vehicle.

We take the guesswork and high dealership costs out of the equation. Each 2005 DeVille Engine Control Module is meticulously programmed to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This means it arrives loaded with the latest factory software from GM, ensuring optimal performance, fuel efficiency, and seamless communication with all other vehicle systems. You get a reliable fix that restores the smooth, powerful driving experience you expect from a Cadillac, without the need for expensive dealer-only programming tools.

A Technician’s Notebook: The Intermittent No-Start

A customer brought in a 2005 DeVille with a maddening problem: it would randomly refuse to start. No crank, no click, nothing. Other times, it would start and run perfectly for days. We checked the battery, starter, and ignition switch—all were fine. The issue was so intermittent that it never acted up in the bay. After hooking up a data logger, we finally caught it. During a no-start event, the ECM was losing communication with the security system (a common U-code scenario). The internal processor was failing under specific temperature conditions. Swapping in a VIN-programmed ECM like this one solved the problem permanently. These intermittent electrical gremlins are classic signs of a dying module.

Is Your Cadillac Showing These Signs?

A failing ECM can manifest in various ways. If you’re experiencing any of the following, this module is the likely solution.

✔ Persistent Check Engine Light (CEL)
✔ Engine stalling or shutting off while driving
✔ No-start or hard-starting conditions
✔ Noticeable decrease in fuel economy
✔ Rough idling or misfires
✔ Harsh or erratic transmission shifting
✔ Communication error codes (e.g., U0100)
✔ Internal module failure codes (e.g., P0601, P0606)

A Straightforward Guide to Installation

Installing your new 2005 DeVille Engine Control Module is a manageable job for a confident DIYer. Since the unit arrives pre-programmed, no special electronic tools are required for the main installation.

Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow the system to fully discharge.
Locate the ECM: On the 2005 Cadillac DeVille, the Engine Control Module is located in the engine compartment on the driver’s side (LH side), typically near the air filter housing.
Disconnect the Connectors: Carefully release the locking tabs on the electrical wiring harnesses and pull them straight out from the module. Avoid pulling on the wires themselves.
Remove the Old Module: Unbolt the old ECM from its mounting bracket. There are usually a few bolts holding it in place.
Install the New Module: Mount the new ECM onto the bracket and securely fasten the bolts.
Reconnect Everything: Plug the wiring harnesses back into the new module until they click firmly into place. Reconnect the negative battery terminal.
Perform Security Relearn (If Needed): In some cases, a simple 10-minute security relearn procedure may be necessary. This typically involves turning the key to the ‘ON’ position for 10 minutes, then off, and then starting the vehicle. Consult your owner’s manual for the specific procedure.

Verified Vehicle Compatibility

This ECM, part number 12630457, is a direct replacement for a wide range of GM vehicles. It is interchangeable with service numbers 12590032, 12602044, 12603530, 12605843, 12607096, and 19210737. Please verify your vehicle is on the list below. Providing your VIN at checkout guarantees we send you a perfectly matched and programmed part.

This part will fit these makes and models with these options

ALLURE 08-09 Electronic Control Module; (lower air cleaner housing), 5.3L
COLORADO 08 Electronic Control Module; (RH firewall)
ENVOY 07-08 Electronic Control Module; 5.3L (LH engine)
ENVOY 08 Electronic Control Module; 4.2L (LH engine), ID 12607096
G6 09 Electronic Control Module; (LH front engine compartment), 3.6L, ID 19210737
MONTE CARLO 06 Electronic Control Module; (lower part of air cleaner box), 3.5L
XLR 09 Electronic Control Module; (RH front engine compartment), ID 12607096
AURA 08-09 Electronic Control Module; (RH firewall), 2.4L, w/hybrid
DTS 06 Electronic Control Module
DEVILLE 05 Electronic Control Module; (LH engine compartment), ID 12590032
G6 07 Electronic Control Module; (LH front engine compartment), 3.6L, ID 12605843
IMPALA 06 Electronic Control Module; (lower part of air cleaner box), 3.5L
LACROSSE 08-09 Electronic Control Module; (lower air cleaner housing), 5.3L
STS 06 Electronic Control Module; (LH frame rail), 4.4L
TRAILBLAZER 08 Electronic Control Module; (LH engine), ID 12636660
UPLANDER 09 Electronic Control Module; (LH engine compartment), (3.9L)
ISUZU ASCENDER 08 Electronic Control Module; (4.2L, LH engine), ID 19210737
SAAB 9-7X 07 Electronic Control Module; (LH engine), 8 cylinder
TRAILBLAZER 07 Electronic Control Module; (LH engine), 5.3L
ENCLAVE 08 Electronic Control Module; (behind fan shroud), ID 19210737
LUCERNE 08 Electronic Control Module; (lower part of air cleaner box), 4.6L, ID 12607096
MONTE CARLO 06 Electronic Control Module; (lower part of air cleaner box), 3.9L
RAINIER 07 Electronic Control Module; (LH engine), 5.3L
ISUZU ASCENDER 08 Electronic Control Module; (4.2L, LH engine), ID 12607096
CTS 06 Electronic Control Module; (RH engine compartment), V-Series, ID 12603530
STS 08 Electronic Control Module; (LH frame rail), 4.6L
G6 06 Electronic Control Module; (LH front engine compartment), ID 12603530
G6 08 Electronic Control Module; (LH front engine compartment), 3.6L
ION 06 Electronic Control Module; 2.4L (opt LE5)
MALIBU 06 Electronic Control Module; 3.9L
MALIBU 08 Electronic Control Module; new style (emblem in bumper cover), 2.4L, w/hybrid
RELAY 06 Electronic Control Module; (LH engine compartment), 3.9L
VUE 08-09 Electronic Control Module; 2.4L, VIN Z (8th digit, opt LAT)
OUTLOOK 08 Electronic Control Module; (behind fan shroud)
SOLSTICE 06 Electronic Control Module; (LH front frame rail)
VUE 08 Electronic Control Module; 3.6L
VUE 09 Electronic Control Module; 3.6L, VIN 7 (8th digit, opt LY7)
ACADIA 07-08 Electronic Control Module; (behind fan shroud), ID 12607096 (ECM)
AURA 08-09 Electronic Control Module; (RH firewall), 3.6L
ENVOY 08 Electronic Control Module; 4.2L (LH engine), ID 19210737
G6 07 Electronic Control Module; (LH front engine compartment), 3.6L, ID 12603530
GRAND PRIX 08 Electronic Control Module; (lower air cleaner box), 5.3L
HHR 06 Electronic Control Module; (LH rear engine compartment), 2.4L
STS 08 Electronic Control Module; (LH frame rail), 4.4L
G6 07 Electronic Control Module; (LH front engine compartment), 3.6L, ID 12590032
ISUZU I-290 08 Electronic Control Module; (RH firewall)
LUCERNE 06 Electronic Control Module; (lower part of air cleaner box), 4.6L
MALIBU 09-10 Electronic Control Module; 2.4L, w/hybrid
UPLANDER 08 Electronic Control Module; (LH engine compartment), (3.9L), ID 19210737
IMPALA 06 Electronic Control Module; (lower part of air cleaner box), 3.9L
MONTANA 06 Electronic Control Module; (LH engine compartment), (SV6), 3.9L
TRAILBLAZER 08 Electronic Control Module; (LH engine), ID 19210737
ENVOY 08 Electronic Control Module; 4.2L (LH engine), ID 12636660
G6 07 Electronic Control Module; (LH front engine compartment), 3.6L, ID 12602044
TRAILBLAZER 08 Electronic Control Module; (LH engine), ID 12607096
TRAILBLAZER 09 Electronic Control Module; (LH engine), 4.2L
CANYON 08 Electronic Control Module; (RH firewall)
COBALT 06 Electronic Control Module; (LH front engine compartment), 2.4L (VIN B, 8th digit, 4-146)
ISUZU I-370 08 Electronic Control Module; (RH firewall)
MALIBU 09 Electronic Control Module; 3.6L
SRX 08 Electronic Control Module; (LH engine compartment), (4.6L)
SAAB 9-7X 08 Electronic Control Module; (LH engine), 5.3L
ENCLAVE 08 Electronic Control Module; (behind fan shroud), ID 12607096
G6 09 Electronic Control Module; (LH front engine compartment), 3.6L, ID 12607096
IMPALA 08-09 Electronic Control Module; (lower part of air cleaner box), 5.3L
XLR 06 Electronic Control Module; (RH front engine compartment), 4.4L
XLR 08 Electronic Control Module; (RH front engine compartment)
ENVOY 09 Electronic Control Module; (LH engine), 4.2L
G6 07 Electronic Control Module; (LH front engine compartment), 3.6L, ID 12607096
G6 07 Electronic Control Module; (LH front engine compartment), 3.6L, ID 12618163
LUCERNE 08 Electronic Control Module; (lower part of air cleaner box), 4.6L, ID 19210737
MONTANA 08-09 Electronic Control Module; (LH engine compartment)
PURSUIT 06 Electronic Control Module; (LH front engine compartment), 2.4L
VUE 10 Electronic Control Module; 3.6L
ACADIA 08 Electronic Control Module; (behind fan shroud), ID 19210737 (PCM)
DTS 08 Electronic Control Module
TERRAZA 06 Electronic Control Module; (LH engine compartment), 3.9L
TRAILBLAZER 07 Electronic Control Module; (LH engine), 6.0L
SAAB 9-7X 08 Electronic Control Module; (LH engine), 6.0L
HUMMER H3 08 Electronic Control Module; (RH firewall)
MALIBU 08 Electronic Control Module; new style (emblem in bumper cover), 3.6L
UPLANDER 08 Electronic Control Module; (LH engine compartment), (3.9L), ID 12607096
UPLANDER 06 Electronic Control Module; (LH engine compartment), 3.9L