Get Your Workhorse Back on the Job with a Reliable Engine Computer
Is your trusty GMC or Chevy truck acting up? Stalling at intersections, shifting erratically, or showing a persistent Check Engine Light? Before you start throwing expensive parts at it, the problem could be its electronic brain: 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 PCM. This isn’t just a part; it’s the central command for your engine and transmission. When it falters, everything falters.
This is a dependable, used OEM PCM that has been professionally tested and prepared for your vehicle. The best part? We handle the programming for you. Simply provide your vehicle’s VIN during checkout, and we’ll flash the module with the latest GM factory software. This means you get a part that’s ready to install right out of the box, saving you a costly trip to the dealership and their programming fees. It’s the smart, straightforward solution to get your truck running like it should.
Case Study: A Tricky Diagnosis
I remember a 1999 Chevy Suburban that came into the shop with a ghost of a problem. The owner complained of intermittent stalling, but only after it was fully warmed up. No specific codes were stored, just a generic U1000 for loss of communication that would appear and disappear. We checked grounds, wiring harnesses, and sensors for hours. Finally, while monitoring live data, I saw the 5-volt reference signal to the sensors flicker and drop out just before it stalled. That pointed directly to an internal failure in the PCM. We swapped in a VIN-programmed module just like this one, and the truck ran perfectly. It’s a classic example of how a failing 1998-1999 GMC 3500 PCM can cause baffling issues that aren’t always obvious.
Is Your Truck or Van Showing These Symptoms?
- âś” Persistent Check Engine Light (CEL)
- âś” Engine stalling or cutting out unexpectedly
- âś” Rough or unstable idle
- âś” Harsh or erratic automatic transmission shifting
- âś” A noticeable drop in fuel economy
- âś” Vehicle won’t start, but the battery and starter are good
- âś” Failure to communicate with a diagnostic scan tool
- âś” Specific Diagnostic Trouble Codes (DTCs) like P0601, P0605, or P0606 indicating internal module failure
A Straightforward Guide to Installation
Replacing the 1998-1999 GMC 3500 PCM is a job most DIYers can handle in their own driveway. Since we program it beforehand, you won’t need any special scan tools for the core installation.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these trucks and vans, you’ll find the PCM in the engine compartment, typically on the driver’s side fender or near the battery.
- Disconnect the Harnesses: Carefully unplug the electrical connectors from the old module. There are usually release tabs you’ll need to press or lift. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. It’s usually held in place by a few small bolts.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and securely fasten it.
- Reconnect Everything: Plug the wiring harnesses back into the new module until they click into place. Reconnect the negative battery terminal.
- Final Steps: In some cases, a security relearn procedure may be needed for the vehicle to start. This typically involves turning the key to the ‘On’ position for 10-15 minutes. Consult your vehicle’s service information for specific steps.
Verified Vehicle Compatibility
This module is a direct replacement for service number 9366810 and other part numbers listed below. It is compatible with a wide range of GM vehicles. Please verify that your vehicle’s original module has service ID 09355699 or one of the compatible numbers. This part fits the following vehicles:
- Chevrolet/GMC C/K 1500, 2500, 3500 Pickups (1998-1999) – Gasoline Engines
- Chevrolet Tahoe / GMC Yukon (1998-1999) – Gasoline Engines
- Chevrolet Suburban / GMC Suburban (1998-1999) – Gasoline Engines
- Cadillac Escalade (1999)
- Chevrolet Express / GMC Savana Vans 1500, 2500, 3500 (1998-1999) – Gasoline Engines
- Chevrolet Astro / GMC Safari (1998)
- Chevrolet S10 / GMC Sonoma (1998) – 4.3L V6
- Chevrolet Blazer / GMC Jimmy (1998) – 4.3L V6
- Oldsmobile Bravada (1998) – 4.3L V6
- Isuzu Hombre (1998) – 4.3L V6
This module replaces part numbers: 09355699, 16266645, 16250279, 16258815, 09366810, 9366810.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential. It allows us to program the PCM with the exact factory software and calibrations for your truck’s specific engine, transmission, and options. This ensures perfect compatibility and performance, just like the original part.
Is this a new part?
No, this is a high-quality, tested used OEM (Original Equipment Manufacturer) part sourced from a salvaged vehicle. We choose OEM parts for their superior reliability and build quality compared to many aftermarket alternatives.
Will I need to do anything after I install it?
Because we pre-program the module, no further computer programming is required. However, some GM vehicles of this era may require a simple ‘Security Relearn’ or ‘Crankshaft Variation Relearn’ procedure to be performed after installation. These can often be done without special tools.
How do I find my old PCM’s part number?
The part number is printed on a sticker on the case of your current PCM. For these GM vehicles, you are looking for the Service Number, which will match one of the numbers listed in our compatibility section, such as 09355699 or 9366810.