Restore Peak Performance to Your GM Vehicle
If you’re dealing with frustrating and unpredictable issues like a no-start condition, rough idling, poor fuel economy, or erratic transmission shifting in your 2003 GMC Savana 2500, the root cause is often a failing Powertrain Control Module (PCM). As the central computer of your vehicle, a faulty PCM can create a diagnostic nightmare. This replacement module, part number 12570558, is the reliable, straightforward solution to get your workhorse van or truck operating like new again.
What sets this part apart is our professional programming service. Before we ship it, we flash the module with the latest official GM software calibrated specifically to your vehicle’s unique Vehicle Identification Number (VIN). This means it arrives at your door ready for installation, saving you the significant time, cost, and hassle of a trip to the dealership for programming. This is the key to a successful and simple repair for both seasoned mechanics and dedicated DIYers.
Case Study: A Tricky Diagnosis
I remember a 2003 Express van that came into my shop with a complaint of intermittent stalling at stoplights. The owner had already replaced the fuel pump and cleaned the throttle body, but the problem persisted. There were no consistent trouble codes, just a random U0100 (Lost Communication with ECM/PCM). After checking the wiring harness for chafing—a common issue on these vans—I focused on the PCM. On the bench, I found a weak 5-volt reference signal that would drop out when the module got hot. Swapping in a pre-programmed PCM like this one solved the problem instantly. The customer was back to work the same day, without the phantom stalling that had been plaguing his business.
Common Signs of a Failing PCM
- âś” Check Engine Light is illuminated with codes like P0601, P0606, or communication errors (U-codes).
- âś” The engine cranks but refuses to start.
- âś” Unexplained drops in fuel efficiency.
- âś” Harsh or incorrect automatic transmission shifts.
- âś” Stalling, stumbling, or rough running conditions.
- âś” Other modules on the vehicle network stop communicating.
A Straightforward Guide to Installation
- âś” Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- âś” Locate the Module: On most Savana/Express vans, the PCM is located in the engine compartment on the driver’s side, near the firewall or master cylinder.
- âś” Disconnect Connectors: Carefully unclip and remove the electrical wiring harness connectors from the old PCM. Inspect them for any corrosion or damage.
- âś” Remove Old PCM: Unbolt the old module from its mounting bracket. It’s typically held by a few small bolts.
- âś” Install New PCM: Mount the new, pre-programmed PCM onto the bracket and securely fasten it.
- âś” Reconnect Everything: Plug the wiring harness connectors firmly into the new module until they click. Reconnect the negative battery terminal.
- âś” Final Step: In some cases, a security relearn procedure may be needed. This is a simple process involving cycling the key and typically takes about 10-15 minutes. We can provide instructions upon request.
Will This Fit My Vehicle?
This module is a direct replacement for service number 12570558 and is compatible with a wide range of GM vehicles. Please verify your model and options below. This part is a confirmed fit for:
- Astro / Safari (GMC) 2003: Electronic Control Module; (LH front by battery)
- Avalanche 2500 2003: Electronic Control Module; (LH front under battery)
- Blazer S10 / Jimmy S15 2003: Electronic Control Module; (RH front engine compartment)
- CTS 2004: Electronic Control Module; (RH engine compartment), Base, ID 12581565
- Corvette 2004: Electronic Control Module; (RH engine compartment), ID 12581565
- Express / Savana 1500, 2500, 3500 Van 2003: Electronic Control Module; (LH rear engine compartment)
- S10 / S15 / Sonoma 2003: Electronic Control Module; (RH front engine compartment), 4.3L
- Sierra / Silverado 1500 Pickup 2003: Electronic Control Module; (LH front under battery), w/4.3L
- Sierra / Silverado 2500 & 3500 Pickup 2003: Electronic Control Module; (LH front under battery), gasoline, 8.1L
- Suburban / Yukon XL 2500 2003: Electronic Control Module; (LH front under battery), 8.1L
This part also replaces the following service numbers: 12581565, 8125815650, 12570557, 12576106, 12576869, 12578127, 8125781270, 88864822, 89017733.
Frequently Asked Questions
Do I need to have this module programmed?
No. We handle all the programming for you before shipment. Simply provide your vehicle’s VIN during or after checkout, and it will arrive ready to install.
What is a VIN and where can I find it?
The VIN is your 17-digit Vehicle Identification Number. You can find it on your driver’s side dashboard (viewable through the windshield), on the driver’s side door jamb sticker, or on your vehicle’s registration and insurance documents.
Will this fix my check engine light?
If your check engine light is caused by an internal failure of the PCM (common codes P0601-P0606), then yes, this will resolve the issue. However, if the light is on for another reason (e.g., a bad sensor), that separate issue will still need to be addressed.
Is this a difficult part to install myself?
For most DIYers with basic tools, this is a very manageable job. The module is typically easy to access, and since we pre-program it, no special electronic tools are needed for the installation.
What if I need to perform a security relearn?
The GM Passlock/Passkey security relearn is a simple, tool-free procedure. It usually involves turning the key to the ‘ON’ position for 10 minutes, then ‘OFF’ for 10 seconds, and repeating this sequence three times. We can provide detailed instructions if needed.