Restore Your Truck’s Brain and Get Back on the Road
Is your trusty GM truck or van suddenly acting possessed? Unexplained stalling, a persistent check engine light, or a frustrating no-start condition can often point to one culprit: a failing Powertrain Control Module (PCM). As a technician with over two decades of experience, I’ve seen firsthand how a faulty PCM can cause a cascade of baffling issues that seem impossible to diagnose. It’s the central computer of your vehicle, and when it fails, everything from fuel delivery to transmission shifting can go haywire.
This isn’t just another part; it’s a reliable, cost-effective solution. You’re getting a genuine, road-tested OEM PCM, part number 9355699, that we program specifically for your vehicle using your VIN. We install the latest GM software updates, ensuring optimal performance and communication with your vehicle’s other modules. This eliminates the expensive trip to the dealership for programming, saving you time and hundreds of dollars in labor. Get the reliability of an original part without the new-part price tag.
Case Study: A Tricky Diagnosis
I remember a 1999 Chevy Tahoe that came into my bay a few years back. The owner had spent a fortune replacing sensors and spark plugs, chasing an intermittent stalling problem that no one could pin down. It would run fine for days, then die at a stoplight without warning. After hooking up my scan tool and monitoring live data, I noticed the fuel trim values would suddenly go erratic just before it stalled. There were no specific sensor codes, just a generic P0601 (Internal Control Module Memory Check Sum Error) that would pop up occasionally. We swapped in a VIN-programmed PCM just like this one, and the problem vanished instantly. It was a classic case of a failing computer brain causing phantom issues.
Is Your Truck or Van Showing These Telltale Signs?
A failing PCM can manifest in many ways. If you’re experiencing any of the following, this module is likely the solution you need. Don’t keep throwing parts at the problem; address the root cause.
- ✔ Check Engine Light is on with codes like P0601, P0605, or P0606.
- ✔ The engine cranks but refuses to start.
- ✔ Intermittent stalling or rough idling for no apparent reason.
- ✔ Noticeably poor fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Communication errors with your scan tool.
- ✔ Failure to pass an emissions test.
A Straightforward Guide to Installation
Installing your programmed 1998-1999 GMC 2500 PCM is a job most DIYers can handle with basic tools. The key is following the steps carefully, especially the security relearn procedure, which is vital for your truck to start.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these GM trucks and vans, the PCM is located in the engine compartment, typically on the driver’s side inner fender or near the battery.
- Disconnect and Remove: Carefully unclip the wiring harness connectors. They have locking tabs, so be gentle. Then, unbolt the module from its mounting bracket.
- Install the New PCM: Bolt your new, pre-programmed PCM into place. Reconnect the wiring harnesses, ensuring they click securely into place. Reconnect the negative battery terminal.
- Perform the Security Relearn: This is a CRITICAL step. Turn the key to the “ON” position (without starting the engine) for 10-12 minutes. The “Security” light on the dash should turn off. Turn the key to “OFF” for 10 seconds. Repeat this cycle two more times (for a total of three cycles). After the third cycle, the vehicle will have learned the new PCM, and you can start the engine.
Verified Vehicle Compatibility
This ECM is a direct fit for a wide range of GM vehicles. Please match your part number (9355699) or one of the interchangeable numbers (16266645, 16250279, 16258815, 09366810) to ensure compatibility. This module fits the following models with ID 9355699:
Frequently Asked Questions
Frequently Asked Questions
Do I need to have this programmed?
No! We handle the programming for you. Simply provide your vehicle’s VIN during or after checkout, and we will flash the module with the latest GM software specific to your truck before shipping it.
What is the ‘Security Relearn Procedure’?
It’s a simple process that syncs the new PCM to your vehicle’s anti-theft system. It involves a few key cycles and takes about 30 minutes. Your truck will not start until this is completed. We’ve included the instructions above.
Is this a new part?
This is a high-quality, used OEM part sourced from a salvaged vehicle. We test every unit to ensure it’s fully functional before programming and shipping.
How do I find my part number?
Your original PCM will have a sticker on it with the service number. It should match 9355699 or one of the interchangeable numbers listed in the description.
What information do you need from me?
All we need is your 17-digit Vehicle Identification Number (VIN). This allows us to program the computer perfectly for your vehicle’s specific configuration.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM also controls transmission functions like shift points and line pressure. If the computer is faulty, it can cause erratic shifting, which a replacement PCM will correct.