Restore Peak Performance to Your GM Workhorse
Is your 1998-1999 GMC Savana 3500 van, or another GM truck from that era, suddenly giving you headaches? Unexplained stalling, rough idling, poor fuel mileage, or a persistent Check Engine Light can often be traced back to a single, critical component: the Powertrain Control Module (PCM). As a technician with over two decades of experience under the hood, I’ve seen countless vehicles sidelined by a failing engine computer. It’s the brain of your vehicle, and when it starts to malfunction, it can cause a cascade of frustrating and hard-to-diagnose issues.
This isn’t just another part pulled from a shelf. This is a dependable, OEM-quality used PCM that we professionally flash with the latest GM software updates specific to your vehicle. By providing us with your Vehicle Identification Number (VIN) at checkout, you receive a module that is ready to be installed, saving you a costly trip to the dealership for programming. This is the smart, efficient solution for getting your reliable GM truck or van back in service, whether you’re a professional mechanic restoring a customer’s vehicle or a DIYer tackling a weekend project. A faulty computer can make even the most robust engine unreliable, but this pre-programmed 1998-1999 Savana 3500 PCM is the direct fix you need.
Case Study: The Intermittent No-Start
A local contractor brought in his ’99 Express 3500 work van that would randomly fail to start. It would crank but never fire. Other times, it ran perfectly. He’d already replaced the fuel pump and crank sensor with no luck. After connecting my scan tool, I noticed communication with the PCM was intermittent. On these GM platforms, heat soak and vibrations eventually cause microscopic cracks in the PCM’s circuit board. We installed one of our VIN-programmed PCMs, performed the quick security relearn, and the problem was gone for good. It’s a classic failure I’ve seen dozens of times, and a correctly programmed module is the only reliable fix.
Is Your Vehicle Showing These Symptoms?
A failing PCM can manifest in various ways. If you’re experiencing any of the following, your engine computer is a likely culprit:
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or other P06xx codes.
- ✔ The engine cranks but won’t start.
- ✔ Stalling for no apparent reason, either while driving or at idle.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass an emissions or smog test.
- ✔ Communication errors with diagnostic scan tools.
A Straightforward Guide to Installation
Installing your replacement 1998-1999 Savana 3500 PCM is a manageable job for a confident DIYer. While specific locations vary slightly by model (see fitment list), the general process is consistent.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the PCM: On most Savana/Express vans, it’s in the engine compartment, typically on the driver’s side near the battery or firewall. On pickups and SUVs, it’s usually on the driver’s side inner fender.
- Disconnect the Connectors: Carefully unclip and remove the large electrical harness connectors. These often have locking tabs or levers; do not force them. Inspect the pins for any corrosion.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. There are typically 2-3 bolts holding it in place.
- Install the New Module: Bolt the new, pre-programmed PCM into the mounting bracket and securely reconnect the electrical harnesses. Ensure they click into place.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform Security Relearn: You will likely need to perform a simple security relearn procedure. This 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.
Verified Vehicle Compatibility
This module, identified by service number 09366810 or interchange ID 9355699, is a direct replacement for a wide range of GM vehicles. Please verify your part number and match it to our list. This part fits the following makes and models:
This module is compatible with numerous 1998-1999 GM models including the Chevrolet Express, GMC Savana, Chevrolet and GMC Pickups (1500, 2500, 3500), Suburban, Tahoe, Yukon, Cadillac Escalade, as well as the S-10, Blazer, Jimmy, Safari, Astro, and more. It interchanges with part numbers 09355699, 16266645, 16250279, 16258815, and 9366810. A correct match is crucial for proper function.
With this reliable and properly programmed 1998-1999 Savana 3500 PCM, you can confidently address your vehicle’s core electronic issues and restore the dependable performance you rely on.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to load the exact, correct software calibration from GM for your specific vehicle. This includes details about the engine, transmission, emissions, and other options, ensuring the module works perfectly right out of the box.
Is this a new part?
No, this is a high-quality, tested used OEM part sourced from a salvaged vehicle. This provides OEM reliability at a significant cost saving compared to a dealership part. Each unit is inspected and then programmed with the latest software.
Will I need to do anything after installation?
After installing the PCM and reconnecting the battery, you will need to perform a security relearn procedure (often called the Passlock or VATS relearn). This is a simple process that typically takes about 30 minutes and involves cycling the ignition key. Instructions are widely available online for your specific model.
What is the difference between a PCM and an ECM?
The terms are often used interchangeably. ECM (Engine Control Module) typically just controls engine functions. A PCM (Powertrain Control Module) controls both the engine and the automatic transmission. For these GM vehicles, it is a PCM.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls transmission line pressure and shift points. If your hard shifting or slipping is caused by an electronic fault within the PCM, this part will resolve it. However, it will not fix internal mechanical failures in the transmission.