Restore Peak Performance to Your GM Vehicle
Is your Chevrolet Astro, Express van, or S10 pickup acting up? If you’re dealing with frustrating issues like a persistent check engine light, rough idling, stalling, or poor fuel economy, the problem often points directly to a failing Powertrain Control Module (PCM). As the brain of your vehicle’s engine and transmission, when the PCM starts to go, it can cause a cascade of confusing problems. I’ve seen it hundreds of times in my 20+ years of diagnostics: a perfectly good engine held back by a faulty computer.
This isn’t just a replacement part; it’s a complete, reliable solution. We are offering a genuine GM-spec PCM, part number 16265035, that comes fully programmed to your vehicle’s specific VIN. We flash it with the latest software updates from GM, ensuring it communicates flawlessly with your vehicle’s systems right out of the box. This eliminates the need for an expensive trip to the dealership for programming, saving you both time and money. Simply provide your VIN at checkout, and we handle the rest.
From the Diagnostic Bay: The Ghost in the Machine
A customer brought in a 2000 Chevy Express van that had been to three other shops. The complaint was intermittent stalling and a no-start condition, but with no consistent trouble codes. They had already replaced the fuel pump, crank sensor, and ignition coil. The van would run fine for days, then suddenly die. After hooking up my scope and monitoring the 5-volt reference signal from the PCM, I saw it intermittently dropping out—a classic sign of an internal PCM failure. We installed one of our pre-programmed modules, and the van has been running perfectly for the owner’s delivery business ever since. This case highlights how a failing 1999-2001 Astro PCM can mimic other component failures, making a quality replacement the true fix.
Common Signs of a Failing PCM
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or other communication errors.
- ✔ Your vehicle fails to start or stalls unexpectedly.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine misfires, runs rough, or hesitates on acceleration.
- ✔ Communication loss with your scan tool.
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- ✔ Locate the PCM: On most compatible vehicles like the Astro or S-series trucks, the PCM is located in the engine bay, often near the battery or on a fender well. On Express/Savana vans, it’s typically in the LH rear engine compartment.
- ✔ Disconnect Connectors: Carefully unclip the wiring harness connectors from the old PCM. These connectors have locking tabs; be gentle to avoid breaking them.
- ✔ Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware as you may need it for the new module.
- ✔ Install the New PCM: Mount your new, pre-programmed PCM and securely re-fasten the bolts.
- ✔ Reconnect Everything: Plug the wiring harnesses back into the new module until they click into place. Reconnect the negative battery terminal.
- ✔ Perform Security Relearn (If Necessary): In many cases, you will need to perform a security relearn procedure, also known as a CASE learn. This simple process typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’, and repeating two more times. This allows the vehicle’s anti-theft system to recognize the new PCM.
Will This Fit My GM Vehicle?
This module is a direct replacement for part numbers 16263494, 16265035, 8162634940, 218-11787, and 21811787. It is guaranteed to fit a wide range of GM trucks and vans. Please verify your vehicle from the list below:
Frequently Asked Questions
Do I need to do anything after installing this PCM?
Because this module comes programmed to your VIN, it’s mostly plug-and-play. However, you will likely need to perform a security relearn procedure (also called CASE learn) which syncs the new PCM with your vehicle’s anti-theft system. This procedure is simple and does not require special tools.
What does ‘VIN Programmed’ mean?
It means we load your vehicle’s unique 17-digit Vehicle Identification Number (VIN) and the latest GM-certified software onto the module before we ship it. This ensures the PCM has the correct parameters for your engine, transmission, and options, making installation much simpler than a blank module.
Is this a reliable fix for my 1999-2001 Astro PCM?
Absolutely. We address the common failure points of the original modules and use software directly from GM. This provides a dependable, long-term solution to restore your vehicle’s factory operation.
Where do I provide my VIN?
You can add your VIN in the notes section during checkout or send it to us in a message after your purchase. We cannot program and ship the module without it.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls both the engine and the transmission. If the module is faulty, it can cause erratic shifting, delayed engagement, or incorrect gear selection. A new, properly programmed PCM often resolves these issues.