Restore Peak Performance to Your GM Truck or Van
Is your trusty 1998-1999 GMC 2500 Pickup acting up? If you’re dealing with frustrating issues like intermittent stalling, poor fuel economy, a persistent check engine light, or erratic transmission shifting, the root cause is often a failing Powertrain Control Module (PCM). As the electronic brain of your vehicle, a faulty PCM can create a cascade of problems that can be difficult to diagnose. This isn’t just a replacement part; it’s a complete, reliable solution designed to get you back on the road with confidence.
We take the guesswork and high cost out of the repair. This is a genuine, road-tested used OEM PCM that we professionally program to your vehicle’s specific Vehicle Identification Number (VIN). Before we ship it, we load it with the latest available software updates from General Motors. This means you get a component that is ready for installation right out of the box, saving you a costly trip to the dealership for programming services. It’s the most effective way to restore the original performance and communication protocols your truck was built with.
Case Study: A Tricky Diagnosis
I remember a ’99 Chevy Suburban that came into my shop with a maddening, intermittent no-start condition. The owner had already replaced the battery, alternator, and fuel pump. There were no hard codes stored, just a history of communication loss faults. After verifying all power and ground circuits to the PCM were solid, I suspected a thermal failure inside the module itself. On a hunch, I carefully used a heat gun on the PCM while the engine was running. Within 30 seconds, the engine sputtered and died. After it cooled, it started right back up. This confirmed the PCM had an internal fracture that only caused a problem when it reached operating temperature. A pre-programmed PCM like this one was the permanent fix.
Common Signs of a Failing PCM
If you’re a DIY enthusiast or a professional technician, you’ve likely seen these symptoms before. A failing PCM can mimic other issues, but here are the classic indicators that point directly to the vehicle’s main computer. Look out for:
- ✔ Check Engine Light is on with internal processor codes like P0601 (Internal Control Module Memory Check Sum Error) or P0605 (Internal Control Module ROM Error).
- ✔ The engine cranks but refuses to start for no apparent reason.
- ✔ Unexplained stalling, especially after the vehicle has warmed up.
- ✔ Noticeably decreased fuel efficiency.
- ✔ The automatic transmission shifts harshly, late, or erratically.
- ✔ Your diagnostic scan tool cannot communicate with the PCM.
A Straightforward Guide to Your PCM Swap
Replacing the PCM on these GM trucks is a job most DIYers can handle in their own driveway with basic hand tools. Our pre-programming service makes it a true plug-and-play repair. Follow these steps for a successful installation of your 1998-1999 GMC 2500 PCM.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Locate the Old PCM: On most of these trucks and vans, the PCM is located in the engine compartment, typically mounted to the driver’s side inner fender or near the battery.
- Disconnect the Harnesses: Carefully inspect the wiring harness connectors. They have locking tabs that need to be released before you can gently pull them straight out. Do not force them.
- Remove the Module: Unbolt the old PCM from its mounting bracket. There are usually two or three bolts holding it in place.
- Install the New PCM: Mount your new, pre-programmed module securely onto the bracket.
- Reconnect Everything: Firmly plug the wiring harnesses back into the correct sockets on the new PCM until they click into place. Reconnect your negative battery terminal.
- Perform Security Relearn: In many cases, you may need to perform a simple security relearn procedure. Turn the key to the ‘ON’ position (without starting) for 10-12 minutes, then turn it ‘OFF’ for 15 seconds. Repeat this cycle three times. On the fourth try, the vehicle should start and run normally.
Will This Fit My Vehicle?
This PCM, identified by service number 09355699, is a direct replacement for several part numbers and fits a wide range of General Motors vehicles from 1998 and 1999. Please verify your vehicle is on the list below and that your original module carries one of the compatible part numbers.
Interchangeable Part Numbers: 09355699, 16266645, 16250279, 16258815, 09366810, 9366810
Compatible Models:
BLAZER S10/JIMMY S15 98 (RH front engine compartment), w/o ZN4, ID 9355699
BRAVADA 98 (6-262, 4.3L), w/o ZN4, ID 9355699
ESCALADE 99 (LH front engine compartment), ID 9355699
CHEVROLET 1500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
CHEVROLET 2500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
CHEVROLET 3500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
GMC 1500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
GMC 2500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
GMC 3500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
ENVOY 98 (RH front engine compartment), w/o ZN4, ID 9355699
EXPRESS/SAVANA 1500 VAN 98-99 ID 9355699
EXPRESS/SAVANA 2500 VAN 98-99 (Gasoline), ID 9355699
EXPRESS/SAVANA 3500 VAN 98-99 (Gasoline), ID 9355699
ISUZU HOMBRE 98 (4.3L), w/o ZN4, ID 9355699
SAFARI (GMC) 98 (LH front by battery), ID 9355699
S10/S15/SONOMA 98 (4.3L), w/o ZN4, ID 9355699
SUBURBAN 1500/2500 98-99 (Gasoline, LH front engine compartment), ID 9355699
TAHOE/YUKON 98-99 (Gasoline, LH engine compartment), ID 9355699
Frequently Asked Questions
Frequently Asked Questions
Do I need to take this part to a dealer for programming?
Absolutely not! The main benefit of our service is that we program the module to your vehicle’s specific VIN before we ship it to you. It arrives ready to install.
What is the difference between a PCM and an ECM?
The terms are often used interchangeably. ECM (Engine Control Module) typically just controls engine functions. PCM (Powertrain Control Module) controls both the engine and the automatic transmission, which is standard for these vehicles.
Is this a new computer?
This is a high-quality, fully tested used OEM module sourced from a salvaged vehicle. This ensures you get the reliability and durability of a genuine factory part at a fraction of the cost.
What information do you need from me after I order?
After you complete your purchase, you will need to provide us with your vehicle’s 17-digit VIN. We cannot program or ship your part without it.
Will this fix my specific problem?
If your vehicle’s issues and diagnostic codes point to a failed PCM, then this part is the correct solution. A proper diagnosis is key to ensuring you’re replacing the right component.
Why is a 1998-1999 GMC 2500 PCM so important for my truck?
The PCM is the central command center. It controls everything from fuel injection and spark timing to transmission shift points. A properly functioning computer is critical for performance, fuel economy, and emissions.