Is Your GM Truck or Van Acting Up?
If you’re dealing with frustrating issues like stalling, erratic shifting, a persistent check engine light, or a no-start condition on your 1998-1999 GM vehicle, the problem often points directly to a failing Powertrain Control Module (PCM). As a mechanic with over two decades of experience, I’ve seen this exact scenario play out hundreds of times. A customer’s 1999 Tahoe came in last week with what they thought was a bad transmission—it was slamming into gear and wouldn’t shift into overdrive. After a quick diagnostic, we traced the fault to a fried driver circuit inside the original PCM, a common failure point on these workhorse vehicles. The PCM is the brain of your engine and transmission, and when it goes, it can cause system-wide chaos.
The Simple, Reliable Solution: Pre-Programmed & Ready to Install
Forget expensive dealership visits and the hassle of finding a shop that can program a new module. This is a genuine, road-tested used OEM PCM that we program specifically for your vehicle before it ships. All you have to do is provide us with your Vehicle Identification Number (VIN) during checkout. We handle the rest, flashing the unit with the latest official GM software updates. This ensures it communicates perfectly with your vehicle’s engine, transmission, and anti-theft system right out of the box.
Expert Pro Tip From a 20-Year Tech
Before you plug in your replacement PCM, take a moment to inspect and clean the main harness connectors with electrical contact cleaner. Over two decades, moisture and grime can build up on the pins, causing a poor connection that can mimic the symptoms of a bad computer. Ensuring a clean, solid connection is a simple step that guarantees your repair is successful from the start.
What to Expect from this 1998-1999 Express 1500 PCM
- ✔ Fixes Common Problems: Directly addresses issues like rough idle, poor fuel economy, harsh shifting, and false sensor codes.
- ✔ VIN-Programmed: Arrives flashed with the latest GM software and tailored to your specific vehicle. No extra programming needed.
- ✔ Cost-Effective Repair: Get a reliable, tested OEM part for a fraction of the cost of a new unit and dealer labor.
- ✔ Broad Compatibility: This module, identified by service number 09355699, is a direct replacement for several part numbers, including 16266645, 16250279, and 16258815.
Plug-and-Play Installation: Get Back on the Road Fast
You can do this job yourself in about 15-20 minutes with basic hand tools. Here’s a general guide:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery.
- Locate Your PCM: On Express/Savana vans, it’s typically in the engine bay on the driver’s side. On pickups and SUVs like the Tahoe or Suburban, it’s also on the driver’s side, near the firewall or inner fender.
- Disconnect the Harnesses: Carefully unclip the colored levers or tabs on the wiring harnesses and pull them straight out from the module.
- Swap the Module: Unbolt the old PCM from its bracket and secure the new one in its place.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new PCM until they click. Reconnect your battery terminal.
- Perform Security Relearn: Your vehicle may require a simple anti-theft relearn. Turn the key to ‘ON’ for 10 minutes, then ‘OFF’ for 10 seconds. Repeat this two more times (30 minutes total). On the fourth try, the vehicle should start.
By ordering this module, you’re not just buying a part; you’re getting a complete, ready-to-go solution that restores your vehicle’s performance and reliability. Provide your VIN, and let us take care of the technical work.