As a technician with over two decades of experience under the hood, I’ve seen firsthand the headaches a failing Powertrain Control Module (PCM) can cause. If your 1998-1999 Chevrolet Express 3500 Van is suddenly running rough, stalling, or throwing a frustrating array of codes, the problem often traces back to this central computer. This isn’t just a part; it’s the brain of your engine, and when it falters, your vehicle’s reliability and performance suffer.
We’re offering a dependable, tested, and ready-to-install solution. This is a genuine, used OEM PCM that has been meticulously inspected. The real value here is our in-house programming service. Before this module ships, we will flash it with the latest official GM software updates, precisely matched to your vehicle’s VIN. This critical step ensures proper communication with all other modules, restores factory performance parameters, and saves you a costly trip to the dealership for programming. You get a part that’s ready to work the moment you install it.
A Technician’s Notebook: The Ghost in the Machine
I remember a 1999 Suburban that came into my bay with a complaint of intermittent stalling and a check engine light. The owner had already replaced the throttle position sensor and the idle air control valve, but the problem persisted. The scanner showed a slew of seemingly unrelated sensor circuit codes. This is a classic sign of a failing PCM. The internal processor was failing, sending out bad data and making good sensors look faulty. We installed a VIN-programmed PCM like this one, performed the security relearn, and the truck ran perfectly. It’s a reminder that sometimes the root cause isn’t a sensor, but the computer interpreting the data.
Is Your GM Truck or Van Showing These Symptoms?
A faulty engine computer can manifest in many ways. If you’re experiencing any of the following, a failing PCM could be the culprit:
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or other communication errors.
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling or rough idling.
- ✔ Noticeably poor fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ The vehicle goes into a reduced power or “limp” mode.
A Straightforward Guide to Installation
Installing your pre-programmed 1998-1999 Express 3500 PCM is a manageable job for a DIYer with basic tools. Following the correct procedure is key to a smooth process.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 15 minutes for the system capacitors to discharge.
- Locate the PCM: On most of these GM trucks and vans, the PCM is located in the engine compartment, typically on the driver’s side fender well or near the battery.
- Disconnect the Connectors: Carefully unclip and remove the electrical wiring harness connectors. These connectors have locking tabs; be gentle to avoid breaking them. Inspect the pins for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Mount your new PCM securely onto the bracket. Reconnect the wiring harnesses, ensuring they click firmly into place.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform Security Relearn: Your vehicle’s anti-theft system (PassLock/VATS) will likely need to be relearned to the new PCM. This procedure is simple and typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine. Specific instructions for your model are readily available online.
Verified Vehicle Compatibility
This module is a direct replacement for service number 16250279 and interchanges with several other part numbers including 09355699, 16266645, 16258815, and 09366810. It is confirmed to fit a wide range of GM trucks and vans. Please verify your part number or consult the list below. We program it specifically for your vehicle using the VIN you provide.
This part fits many models including, but not limited to:
- ✔ 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline)
- ✔ 1998-1999 Chevrolet Suburban & GMC Suburban 1500, 2500 (Gasoline)
- ✔ 1998-1999 Chevrolet Tahoe & GMC Yukon (Gasoline)
- ✔ 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans (Gasoline)
- ✔ 1999 Cadillac Escalade
- ✔ 1998 Chevrolet Astro & GMC Safari
- ✔ 1998 Oldsmobile Bravada, S10 Blazer, GMC S15 Jimmy, Isuzu Hombre (4.3L)
This is a cost-effective and reliable way to get your workhorse van or truck back in service. By providing a quality used part with fresh, VIN-specific programming, we eliminate the guesswork and high costs associated with engine computer replacement. Let us help you get back on the road with confidence.
Frequently Asked Questions
Do I need to do anything after installing this PCM?
Yes. While we program the module to your VIN, you will need to perform a simple security relearn procedure (also known as a VATS or PassLock relearn). This syncs the new PCM with your vehicle’s anti-theft system and typically takes about 30 minutes with no special tools required.
Is this a new part?
No, this is a high-quality, tested, and guaranteed functional used OEM part sourced from a salvaged vehicle. This allows us to provide a reliable and affordable solution.
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential. It allows us to program the PCM with the exact software and calibrations your vehicle had from the factory, including any official GM updates. This ensures perfect compatibility and performance.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the old PCM (like code P0601), then yes, this part will resolve the issue. However, if the light is on due to a faulty sensor or other system problem, you will still need to diagnose and repair that separate issue.
How do I find my PCM part number?
The part number is printed on a sticker on the case of your existing PCM. You may need to unbolt it to see the label clearly. Matching the service number (e.g., 16250279) is the best way to ensure compatibility.