Get Your GM Truck Back on the Road with a Reliable, Programmed PCM
As a technician with over two decades of experience under the hood, I’ve seen countless trucks and SUVs sidelined by a faulty Powertrain Control Module (PCM). The symptoms can be maddening: one day it’s a no-start, the next it’s stalling at a stoplight, or the transmission is shifting erratically. If your 1998 Blazer, Jimmy, or another compatible GM vehicle is giving you headaches, this professionally programmed PCM is the straightforward, dependable solution you need. This isn’t just a used part; it’s a tested, VIN-matched brain for your vehicle, ready to restore its performance and reliability.
The PCM is the central command center, managing everything from fuel injection and spark timing to transmission shift points and emissions controls. When it fails, the entire vehicle suffers. This unit, which interchanges with part number 9355699, eliminates the guesswork. We take your vehicle’s VIN and flash this computer with the latest official GM software specific to your truck. This ensures all factory parameters are correct, providing a seamless installation and restoring the performance you’ve been missing. Don’t let a bad computer keep your trusty GM off the road. This is the fix that gets you running right again.
Case Study: A Tricky Diagnosis
I remember a 1998 GMC Jimmy S15 that came into the shop with a ghost of a problem. The owner complained of intermittent stalling and a random Check Engine Light that would come and go. We checked the fuel pressure, ignition system, and sensors—all tested fine. The codes were inconsistent, pointing to different systems each time. After hours of diagnostics, we focused on the PCM itself. On these models, internal board failures, often due to heat cycles and age, can cause these exact unpredictable symptoms. We swapped in a VIN-programmed PCM like this one, performed the security relearn, and the Jimmy ran perfectly. The owner was back on the road the same day, problem solved. It’s a classic example of how a failing 1998 Blazer S10 PCM can mimic a dozen other issues.
Is Your Truck or Van Showing These Signs?
A failing PCM can cause a wide range of issues. If you’re experiencing any of the following, a faulty engine computer is a likely culprit:
- ✔ Check Engine Light is on with communication codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (ECM/PCM Processor Fault).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling, especially when coming to a stop or at idle.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ A noticeable drop in fuel economy.
- ✔ Failure to pass an emissions test.
- ✔ The vehicle runs poorly, with hesitation or misfires that aren’t related to plugs or coils.
A Straightforward Guide to Installation
Installing your programmed PCM is a job most DIYers can handle with basic tools. This module is typically located in the engine bay, making access relatively simple.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent any accidental reconnection.
- Locate the PCM: On most S-10 Blazers and Jimmys, the PCM is on the RH (passenger) side of the engine compartment. On full-size trucks and vans, it’s often on the LH (driver) side. It’s a silver metal box with multiple large electrical connectors.
- Disconnect the Connectors: Carefully unclip and remove all wiring harness connectors from the old PCM. These connectors have locking tabs that need to be released before pulling. Avoid forcing them.
- Remove the Old Module: Unbolt the PCM from its mounting bracket and remove it from the vehicle.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and securely fasten the bolts.
- Reconnect Everything: Plug the wiring harness connectors firmly into the new PCM until they click into place. Reconnect your vehicle’s negative battery terminal.
- Perform Security Relearn: You will likely need to perform a simple security relearn procedure (often called a CASE learn or Passlock relearn). This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows the vehicle’s anti-theft system to recognize the new PCM.
Verified Vehicle Compatibility
This PCM is a direct replacement for service ID 9355699 and part number 16258815. It is guaranteed to fit the following GM vehicles. Please match your service ID number to ensure compatibility.
- 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline)
- 1998-1999 Chevrolet Suburban 1500 & 2500 (Gasoline)
- 1998-1999 Chevrolet Tahoe & GMC Yukon (Gasoline)
- 1999 Cadillac Escalade
- 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans (Gasoline)
- 1998 Chevrolet Astro & GMC Safari Vans
- 1998 Chevrolet S10 / GMC Sonoma (4.3L V6)
- 1998 Chevrolet Blazer S10 / GMC Jimmy S15 (4.3L V6)
- 1998 Oldsmobile Bravada (4.3L V6)
- 1998 GMC Envoy (4.3L V6)
- 1998 Isuzu Hombre (4.3L V6)
Frequently Asked Questions
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential. We use it to load the exact, correct GM factory software for your vehicle’s specific engine, transmission, and options. This ensures a perfect match and proper function right out of the box.
Is this a plug-and-play part?
Yes, for the most part. Because we pre-program it to your VIN, it eliminates the need for expensive dealer scan tools. However, you will need to perform a simple security relearn procedure after installation, which can be done without any special tools.
What is a security relearn / CASE learn?
It’s a simple procedure that syncs the new PCM with your vehicle’s anti-theft and security system. It usually involves a sequence of key turns and waiting periods. Instructions are widely available online for your specific model, or you can ask your mechanic.
This part is used. How do I know it’s reliable?
Every computer we sell is sourced from a salvaged vehicle and then thoroughly inspected and tested to ensure it is fully functional. We then flash it with fresh, updated software, making it a reliable and cost-effective alternative to a new part.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls the transmission solenoids and shift logic. If your hard or erratic shifting is caused by a faulty computer, this part will resolve it. If the problem is mechanical within the transmission, this will not fix it.