Get Your GM Truck Running Right Again
As a technician with over two decades of experience, I’ve seen firsthand the frustration a failing Powertrain Control Module (PCM) can cause. Your 1998-1999 Chevrolet 1500 Pickup is a workhorse, but when its electronic brain starts to falter, you’ll notice everything from erratic engine behavior to a complete no-start situation. This isn’t just an inconvenience; it’s a problem that affects your truck’s reliability and performance. That’s why we offer this fully tested, used OEM PCM, identified by part number 9355699.
The real value here isn’t just the part itself—it’s the service. Before this module ships, we flash it with the latest official GM software updates, precisely programmed to your truck’s specific Vehicle Identification Number (VIN). This critical step ensures seamless communication between the engine, transmission, and other systems, eliminating the need for an expensive trip to the dealership for programming. You get a component that’s ready to install right out of the box, restoring the dependable performance you expect from your Chevy.
A Technician’s Notebook: The Intermittent Stall
I remember a ’99 Silverado 5.7L that came into my bay with a ghost of a problem. The owner said it would randomly stall at red lights, but then fire right back up. No consistent Check Engine Light, just unpredictable shutdowns. After checking fuel pressure, spark, and sensors—all of which tested fine—I hooked up my scanner and monitored the live data. I noticed the PCM was momentarily losing its 5-volt reference signal. A visual inspection of the module revealed a small amount of corrosion on one of the pins from a leaky cowl. We swapped in a quality used PCM, programmed it to the VIN, and the stalling issue was gone for good. It’s often these subtle internal failures that cause the biggest headaches.
Is Your Truck Showing These Symptoms?
A faulty PCM can manifest in numerous ways. If you’re experiencing any of the following, a failing engine computer could be the culprit. I’ve often traced these issues back to the PCM after ruling out more common mechanical failures.
- ✔ Check Engine Light is illuminated with codes like P0601 (Internal Control Module Memory Check Sum Error) or other P06xx processor faults.
- ✔ Your engine cranks but refuses to start.
- ✔ Unexplained drops in fuel economy.
- ✔ The engine stalls, stumbles, or runs rough intermittently.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass an emissions inspection.
A Straightforward Guide to Installation
Installing your programmed 1998-1999 Chevrolet 1500 PCM is a job most DIYers can handle in their own driveway. The key is to be patient and methodical. No specialized diagnostic tools are required for the physical swap.
- Safety First: Always disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these trucks, the PCM is found in the engine compartment, typically on the driver’s side fender or near the firewall.
- Disconnect the Old Unit: Carefully unplug the electrical connectors. These GM connectors from the 90s often have locking tabs that need to be released. Avoid pulling on the wires themselves.
- Remove the Module: Unbolt the old PCM from its mounting bracket.
- Install the New PCM: Mount your replacement module securely in the bracket and firmly reconnect all electrical connectors until they click into place.
- Reconnect Power: Reattach the negative battery terminal and tighten it securely.
- Security Relearn (If Needed): In some cases, you may need to perform a simple security relearn procedure. Turn the key to the ‘ON’ position for 10-15 minutes, then turn it off for 10 seconds. Repeat this cycle three times. This allows the new PCM to synchronize with your vehicle’s anti-theft system. Your truck should now start and run correctly.
Verified Vehicle Compatibility
This module, part number 9355699, is a direct replacement for a wide range of GM trucks and vans. Please verify your original part number or match your vehicle in the list below to ensure proper fitment. This unit replaces service numbers: 09355699, 16266645, 16250279, 16258815, 09366810, and 9366810.
Fits models such as:
- 1998-1999 Chevrolet/GMC 1500/2500/3500 Pickup (Gasoline)
- 1998-1999 Chevrolet Tahoe / GMC Yukon (Gasoline)
- 1998-1999 Chevrolet Suburban 1500/2500 (Gasoline)
- 1999 Cadillac Escalade
- 1998-1999 Chevrolet Express / GMC Savana Van 1500/2500/3500 (Gasoline)
- 1998 Chevrolet S10 / GMC Sonoma / Isuzu Hombre (4.3L V6)
- 1998 Chevrolet Blazer / GMC Jimmy / Oldsmobile Bravada (4.3L V6)
- 1998 Chevrolet Astro / GMC Safari Van
Frequently Asked Questions
1998-1999 Chevrolet 1500 PCM
What if this doesn’t fix my problem?
While this fixes many common issues, proper vehicle diagnosis is key. We recommend confirming your PCM is the source of the fault. If other components like sensors or wiring are faulty, replacing the PCM will not solve the issue.