Get Your Heavy-Duty Chevy Back on the Job
Is your 1998-1999 Chevrolet 3500 Pickup suddenly unreliable? A failing Powertrain Control Module (PCM), the brain of your truck’s engine and transmission, can cause a host of frustrating issues that leave you stranded. From a stubborn no-start condition to erratic shifting and a persistent Check Engine Light, a faulty PCM can cripple your workhorse. This reliable, tested Powertrain Control Module is the definitive solution to restore your truck’s performance and dependability. We take the guesswork out of the repair by programming it specifically to your vehicle’s VIN before it ships, ensuring a seamless installation process.
Case Study: A Tricky Diagnosis
I once had a ’99 Chevy K3500 dually in my bay that was a real head-scratcher. The owner was convinced his transmission was shot—it was shifting hard, hunting for gears, and sometimes wouldn’t go into overdrive. He’d already replaced the vehicle speed sensor. We scanned it and found no specific transmission codes, just a generic U-code for lost communication. Instead of tearing into the transmission, we hooked up a scope to the PCM communication lines. The data stream was erratic and dropping out. We swapped in a known-good, programmed PCM, and the truck drove perfectly. The original module’s internal processor was failing under load, mimicking a major transmission failure. It saved the customer thousands and reinforced a key lesson: always verify the controller is healthy before replacing expensive components.
Common Signs of a Failing PCM
- ✔ Persistent Check Engine Light with codes like P0601 (Internal Control Module Memory Error) or P0605 (Read Only Memory Error).
- ✔ Engine stalling, stumbling, or refusing to start, even with a good battery and fuel supply.
- ✔ Noticeable decrease in fuel economy and poor engine performance.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Communication errors with diagnostic scan tools.
- ✔ Seemingly random sensor codes appearing and disappearing.
The Advantage of a Pre-Programmed 1998-1999 Chevrolet 3500 PCM
The biggest hurdle in replacing a modern vehicle computer is the programming. This used OEM module eliminates that step entirely. We flash it with the latest GM-certified software using the VIN you provide at checkout. This means it arrives ready to install, saving you a costly trip to the dealership and hours of diagnostic headaches. It’s a cost-effective and efficient way to solve complex electronic issues and get your truck running like it should.
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your truck’s battery and secure it away from the post to prevent any accidental power surges.
- ✔ Locate the PCM: On most of these GMT400 trucks, the PCM is located in the engine compartment on the driver’s side, near the fender or firewall. It’s a silver metal box with multiple large wiring harness connectors.
- ✔ Disconnect the Harnesses: Carefully unclip and remove the electrical connectors from the old PCM. These connectors have locking tabs that need to be released. Avoid pulling on the wires themselves.
- ✔ Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware, as you may need to reuse it.
- ✔ Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten it.
- ✔ Reconnect Everything: Firmly plug the wiring harnesses into the new module until they click into place. Reconnect your battery’s negative terminal.
- ✔ Perform Security Relearn (If Needed): In some cases, you may need to perform a simple security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your vehicle’s service information for the exact steps.
Verified Vehicle Compatibility
This Electronic Control Module is a guaranteed fit for a wide range of GM trucks and vans. It is a direct replacement for part numbers 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. Please verify your original part number or consult the list below. This module fits gasoline-engine models including:
- 1998-1999 Chevrolet & GMC 1500, 2500, & 3500 Pickups
- 1998-1999 Chevrolet Tahoe & GMC Yukon
- 1998-1999 Chevrolet & GMC Suburban 1500 & 2500
- 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, & 3500 Vans
- 1999 Cadillac Escalade
- 1998 Chevrolet Astro & GMC Safari
- 1998 Oldsmobile Bravada, GMC Envoy, Chevrolet S10 Blazer, GMC S15 Jimmy
- 1998 Chevrolet S10 / GMC Sonoma (4.3L)
- 1998 Isuzu Hombre (4.3L)
Frequently Asked Questions
Do I need to do anything after installing this PCM?
Because we program the module to your VIN, it’s typically a plug-and-play installation. However, some vehicles may require a simple security relearn procedure, also known as a Passlock or VATS relearn, which can be done without special tools.
What information do you need from me?
After you complete your purchase, you must provide us with your vehicle’s 17-digit Vehicle Identification Number (VIN). This is essential for us to load the correct GM software and vehicle-specific parameters onto the module.
Is this a new part?
No, this is a high-quality, tested used OEM part sourced from a salvaged vehicle. Each unit is inspected and verified to be fully functional before being programmed and shipped.
Will this fix my truck’s no-start problem?
A failing PCM is a very common cause of no-start or intermittent start conditions on these vehicles. If you have ruled out fuel, spark, and battery issues, and especially if you have communication-related DTCs, this module is a very likely solution.
How do I find my original part number?
The part number is printed on a sticker on the case of your current PCM. Matching it to one of the compatible numbers listed (e.g., 16266645 or 09355699) ensures you are ordering the correct hardware.