Programmed 2003 Silverado 3500 PCM IS 8125815650 | VIN-Matched & Updated

Restore Peak Performance to Your GM Truck or Van

As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing Powertrain Control Module (PCM) can bring even the toughest trucks to their knees. If you’re dealing with frustrating issues like a persistent check engine light, erratic engine behavior, or transmission shifting problems in your 2003 Silverado 3500, this module is the reliable, straightforward solution you need. This isn’t just a replacement part; it’s the restored brain for your vehicle’s engine and transmission, designed to get you back on the road with confidence.

We take the guesswork and extra expense out of the equation. Each module is professionally programmed with the latest official GM software updates specifically for your vehicle. All we need is your Vehicle Identification Number (VIN) during checkout. This ensures that when the part arrives, it’s ready to communicate perfectly with your truck’s systems, restoring the original factory performance and efficiency. This is the same process a dealership would follow, but without the high labor costs and scheduling delays.

Is Your Vehicle Showing These Symptoms?

A faulty PCM can cause a wide range of problems. If you’re experiencing any of the following, it’s a strong indicator that your engine’s computer needs attention:

• ✔ Check Engine Light is on with codes like P0601, P0606, or other internal processor faults.
• ✔ The engine cranks but refuses to start.
• ✔ Poor or erratic automatic transmission shifting.
• ✔ A noticeable drop in fuel economy.
• ✔ The engine stalls, stumbles, or misfires intermittently.
• ✔ Failure to pass an emissions test.
• ✔ Communication errors with diagnostic scan tools.

A Straightforward Guide to Installation

Replacing the 2003 Silverado 3500 PCM is a job most DIYers can handle with basic tools. The module is typically located under the hood on the driver’s side, near the battery. Follow these general steps for a successful installation:

1. Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any electrical work.
2. Locate the PCM: On most GM trucks and vans from this era, you’ll find the PCM mounted to a bracket on the driver’s side inner fender, just below the battery tray.
3. Disconnect the Connectors: Carefully unlatch and remove the electrical harness connectors from the old module. Inspect them for any corrosion or damage.
4. Remove the Old Module: Unbolt the PCM from its mounting bracket. It’s usually held in place by a couple of small bolts.
5. Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock into place.
6. Reconnect the Battery: Reattach the negative battery terminal.
7. Perform Security Relearn: You will likely need to perform a simple security relearn procedure (often called a ‘key-on’ relearn) to sync the new PCM with your vehicle’s anti-theft system. This typically involves turning the key to the ‘ON’ position for 10-15 minutes. Instructions will be provided.

Will This Fit My Vehicle?

This module is a direct-fit replacement for a wide range of GM vehicles and is compatible with numerous service numbers, ensuring broad applicability. Please verify your vehicle is on the list below. This part replaces service numbers: 12581565, IS 8125815650, 12570557, 12570558, 12576106, 12576869, 12578127, 8125781270, 88864822, and 89017733.

• AVALANCHE 2500 (2003): Electronic Control Module; (LH front under battery)
• ASTRO / SAFARI (GMC) (2003): Electronic Control Module; (LH front by battery)
• BLAZER S10 / JIMMY S15 (2003): Electronic Control Module; (RH front engine compartment)
• CADILLAC CTS (2004): Electronic Control Module; (RH engine compartment), Base, ID 12581565
• CHEVROLET CORVETTE (2004): Electronic Control Module; (RH engine compartment), ID 12581565
• EXPRESS / SAVANA VANS (1500, 2500, 3500) (2003): Electronic Control Module; (LH rear engine compartment)
• S10 / S15 / SONOMA (2003): Electronic Control Module; (RH front engine compartment), 4.3L
• SIERRA 1500 PICKUP (2003): Electronic Control Module; (LH front under battery), w/4.3L
• SIERRA / SILVERADO 2500 PICKUP (2003): Powertrain Control Module; (LH front under battery), gasoline, 8.1L
• SIERRA / SILVERADO 3500 PICKUP (2003): Engine Control Module; (LH front under battery), gasoline, 8.1L
• SUBURBAN / YUKON XL 2500 (2003): Electronic Control Module; (LH front under battery), 8.1L

Frequently Asked Questions About This 2003 Silverado 3500 PCM