If you’re dealing with frustrating and unpredictable issues in your 2008-2009 Pontiac Montana, a failing Engine Control Module (ECM) is often the hidden culprit. As the central computer for your engine, its health is critical for everything from starting the engine to fuel efficiency. This isn’t just a replacement part; it’s a reliable, long-term solution designed to restore your vehicle’s performance and get you back on the road with confidence.
We take the guesswork and high dealership costs out of the equation. Before this module ships, we program it specifically to your vehicle using your VIN. This ensures it arrives loaded with the latest GM factory software updates, making it a true plug-and-play component. You get a part that’s ready for installation right out of the box, eliminating the need for expensive scan tools or a trip to the dealer for programming.
A Technician’s Notebook: The Intermittent Gremlin
I once had a 2009 Pontiac Montana in my bay that was driving its owner crazy. It would randomly stall at stoplights, sometimes refuse to start for an hour, and then run perfectly for days. The check engine light was intermittent. The owner had already replaced the battery and alternator. After connecting my diagnostic scanner, I saw a few communication loss codes (U-codes) stored in history, but nothing active. These are classic signs of a failing ECM. The internal processors start to break down, causing unpredictable behavior that doesn’t always set a hard fault code. We installed one of our VIN-programmed ECMs, and the van ran flawlessly. It’s a textbook case of how a faulty module can mimic a dozen other problems, and why a reliable replacement is key.
Is Your Montana Showing These Symptoms?
A failing ECM can cause a wide range of problems. If you’re experiencing any of the following, your engine’s computer may be at fault:
- ✔ Check Engine Light is on or flashes intermittently
- ✔ Engine cranks but refuses to start
- ✔ Stalling, stumbling, or rough idling
- ✔ Noticeable decrease in fuel economy
- ✔ Poor engine performance or loss of power
- ✔ Transmission shifting issues or harsh shifts
- ✔ Diagnostic Trouble Codes (DTCs) such as P0601, P0606, or U0100
Your Straightforward Installation Guide
Replacing the ECM on your Pontiac Montana is a manageable job for a confident DIYer. The module is typically located in the left-hand (driver’s side) engine compartment.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any electrical work.
- Locate the ECM: Open the hood and find the ECM on the driver’s side of the engine compartment. It’s a silver box with several large electrical connectors.
- Disconnect the Connectors: Carefully release the locking tabs on each electrical harness connector and pull them straight off the module. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the ECM from its mounting bracket. Keep the bolts and any hardware in a safe place.
- Install the New ECM: Mount your new, pre-programmed ECM onto the bracket and secure it with the original bolts.
- Reconnect Everything: Firmly plug the electrical connectors back into the new module until they click into place. Reconnect the negative battery terminal.
- Final Step: Some vehicles may require a security relearn procedure, which can typically be done without special tools. Turn the key to the ‘ON’ position for 10-15 minutes, then off, and then start the engine.
Verified Vehicle Compatibility
This ECM is a direct replacement for service number 12603530 and is also interchangeable with part numbers 12590032, 12602044, 12605843, 12607096, 12630457, and 19210737. It fits a wide array of GM vehicles. Please confirm your model and options below.
MONTANA 06 Electronic Control Module; (LH engine compartment), (SV6), 3.9L
ACADIA 07-08 Electronic Control Module; (behind fan shroud), ID 12607096 (ECM)
ACADIA 08 Electronic Control Module; (behind fan shroud), ID 19210737 (PCM)
ALLURE 08-09 Electronic Control Module; (lower air cleaner housing), 5.3L
AURA 08-09 Electronic Control Module; (RH firewall), 2.4L, w/hybrid
AURA 08-09 Electronic Control Module; (RH firewall), 3.6L
CANYON 08 Electronic Control Module; (RH firewall)
COBALT 06 Electronic Control Module; (LH front engine compartment), 2.4L (VIN B, 8th digit, 4-146)
COLORADO 08 Electronic Control Module; (RH firewall)
CTS 06 Electronic Control Module; (RH engine compartment), V-Series, ID 12603530
DEVILLE 05 Electronic Control Module; (LH engine compartment), ID 12590032
DTS 06, 08 Electronic Control Module
ENCLAVE 08 Electronic Control Module; (behind fan shroud), ID 12607096 or 19210737
ENVOY 07-09 & ISUZU ASCENDER 07-08 (Multiple Engines & IDs – Please Verify)
G6 06-09 (Multiple Engines & IDs – Please Verify)
GRAND PRIX 08 Electronic Control Module; (lower air cleaner box), 5.3L
HHR 06 Electronic Control Module; (LH rear engine compartment), 2.4L
HUMMER H3 08 Electronic Control Module; (RH firewall)
IMPALA 06, 08-09 (Multiple Engines – Please Verify)
ION 06 Electronic Control Module; 2.4L (opt LE5)
ISUZU I-290 & I-370 08 Electronic Control Module; (RH firewall)
LACROSSE 08-09 Electronic Control Module; (lower air cleaner housing), 5.3L
LUCERNE 06, 08 (Multiple Engines & IDs – Please Verify)
MALIBU 06, 08-10 (Multiple Engines & Styles – Please Verify)
MONTE CARLO 06 Electronic Control Module; (lower part of air cleaner box), 3.5L or 3.9L
OUTLOOK 08 Electronic Control Module; (behind fan shroud)
PURSUIT 06 Electronic Control Module; (LH front engine compartment), 2.4L
RAINIER 07 Electronic Control Module; (LH engine), 5.3L
RELAY 06 Electronic Control Module; (LH engine compartment), 3.9L
SAAB 9-7X 07-08 (Multiple Engines – Please Verify)
SOLSTICE 06 Electronic Control Module; (LH front frame rail)
SRX 08 Electronic Control Module; (LH engine compartment), (4.6L)
STS 06, 08 (Multiple Engines & IDs – Please Verify)
TERRAZA 06 Electronic Control Module; (LH engine compartment), 3.9L
TRAILBLAZER 07-09 (Multiple Engines & IDs – Please Verify)
UPLANDER 06, 08-09 (Multiple Engines & IDs – Please Verify)
VUE 08-10 (Multiple Engines & VINs – Please Verify)
XLR 06, 08-09 (Multiple Engines & IDs – Please Verify)
Do I need to program this ECM?
Do I need to program this ECM?
No. We handle all the programming for you before shipment. Simply provide your vehicle’s VIN during checkout, and we will flash the module with the latest GM software specific to your Montana. It arrives ready to install.
Where can I find my vehicle’s VIN?
Your 17-digit Vehicle Identification Number (VIN) can be found on your vehicle’s registration, insurance card, or on the driver’s side of the dashboard, visible through the windshield.
Is this part difficult to install?
For most individuals with basic mechanical skills, this is a straightforward replacement. It involves disconnecting the battery, unplugging a few connectors, and unbolting the old module. Our pre-programming service eliminates the most difficult part of the job.
How do I know my old ECM is really the problem?
While the symptoms listed above are strong indicators, a definitive diagnosis is always recommended. A professional mechanic can test the circuits and confirm the ECM is at fault. Common fault codes like P0601 (Internal Memory Error) are a very clear sign that the ECM needs replacement.