Restore Your Truck’s Brain and Get Back on the Road
Is your 1998 Chevy Blazer, GMC Jimmy, or another GM truck from that era giving you headaches? If you’re dealing with frustrating issues like random stalling, a persistent check engine light, poor fuel mileage, or harsh shifting, the problem often points directly to a failing Powertrain Control Module (PCM). As the central computer of your vehicle, the PCM manages everything from fuel injection and ignition timing to transmission operation. When it fails, your vehicle’s performance and reliability suffer dramatically.
This isn’t just another part pulled from a yard. This is a dependable, tested, used OEM PCM that we program specifically for your vehicle before it ever leaves our facility. Simply provide us with your Vehicle Identification Number (VIN) during checkout, and our technicians will flash the module with the latest GM-certified software for your exact make and model. This critical step ensures proper communication between all your vehicle’s systems, restoring the performance and efficiency you’ve been missing. By getting a pre-programmed 1998 Blazer S10 PCM, you bypass the expensive and time-consuming trip to the dealership for programming.
From the Diagnostic Bay: The Ghost in the Machine
I remember a 1998 GMC Sonoma that came into my shop a few years back. The owner was at his wit’s end. He’d replaced the fuel pump, spark plugs, and even the distributor, but the truck would still randomly die at stoplights and refuse to restart for 10-15 minutes. No consistent codes, just pure frustration. After hooking up my scope and monitoring the 5-volt reference signal from the PCM, I saw it—intermittent voltage drops that coincided with the stalling. The PCM’s internal voltage regulator was failing when it got hot. A replacement, programmed PCM like this one solved the problem instantly. It’s often the last part people suspect, but the first part that should be properly diagnosed.
Is Your Truck Showing These Signs?
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, a faulty computer is a likely culprit:
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0605 (Internal Control Module Read Only Memory (ROM) Error).
- ✔ The engine cranks but won’t start.
- ✔ Unexplained stalling or rough idling, especially after the engine warms up.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Communication errors with your scan tool.
A Straightforward Guide to Installation
Installing your programmed 1998 Blazer S10 PCM is a job most DIYers can handle with basic tools. Following these steps will ensure a smooth replacement.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent any accidental power surges.
- Locate the PCM: On the 1998 Blazer/Jimmy, the PCM is typically located in the engine compartment on the passenger side (RH side), near the firewall. Other vehicles on the fitment list may have it on the driver’s side (LH side) or near the battery.
- Disconnect the Connectors: Carefully unclip and remove the wiring harness connectors from the old PCM. These connectors have locking tabs; be gentle to avoid breaking them. Inspect the terminals for any corrosion or damage.
- Remove the Old Module: Unbolt the mounting brackets holding the old PCM in place and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed PCM securely in the same location. Reconnect the wiring harnesses, ensuring they click firmly into place.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform Security Relearn (If Necessary): While we program the module to your VIN, some GM vehicles of this era require a simple key-cycle security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine.
Will This Fit My Vehicle?
This PCM is a direct replacement for service number 16266645 and interchanges with part numbers 09355699, 9355699, 16250279, 16258815, 09366810, and 9366810. Please verify your part number and check the extensive list below for compatibility. This unit fits a wide range of 1998-1999 GM trucks and vans.
– ASTRO/SAFARI (GMC) 98: (LH front by battery)
– BLAZER S10/JIMMY S15 98: (RH front engine compartment), w/o build date opt ZN4
– BRAVADA 98: (6-262, 4.3L), w/o build date opt ZN4
– ENVOY 98: (RH front engine compartment), w/o build date opt ZN4
– ESCALADE 99: (LH front engine compartment)
– EXPRESS/SAVANA 1500, 2500, 3500 (98-99): Gasoline engines
– HOMBRE (ISUZU) 98: 4.3L (6 cylinder), w/o extended build date opt ZN4
– S10/S15/SONOMA 98: 6-262 (4.3L), w/o build date opt ZN4
– PICKUP (1500/2500/3500) 98-99: Gasoline engines (5.0L, 5.7L)
– SUBURBAN (1500/2500) 98-99: Gasoline engines
– TAHOE/YUKON 98-99: Gasoline engines
Frequently Asked Questions
What is VIN programming and why do I need it?
VIN programming is the process of loading your vehicle’s specific software onto the PCM. It ensures the computer correctly manages your engine, transmission, and options package. Without it, the vehicle may not start or run properly. We handle this for you before shipping.
Is this part truly plug-and-play?
Because we program it to your VIN, it is as close to plug-and-play as possible. In some cases, a simple 30-minute security relearn procedure (key cycle) is required after installation, which you can do yourself without any special tools.
This is a used part. How can I trust it?
Every module we sell is sourced from a salvaged vehicle and thoroughly tested to ensure full functionality. We guarantee the programming and the hardware, offering you a reliable and cost-effective solution compared to a new dealership part.
What happens if I don’t provide my VIN?
We cannot ship the PCM until we have your VIN. The programming is essential for the part to work in your vehicle. Please provide your 17-digit VIN in the notes at checkout or send us a message after your purchase to avoid delays.
My original part number is slightly different, but it’s on the interchange list. Will this work?
Yes. Manufacturers often use several part numbers for the same component. As long as your original number is on our cross-reference list (e.g., 09355699, 16250279), this PCM will function correctly once programmed to your VIN.