Restore Peak Performance to Your GM Truck or SUV
Is your trusty 1998 GMC Envoy, Chevy truck, or Savana van running rough, shifting erratically, or refusing to start? Before you start throwing parts at it, the problem might be its electronic brain: the Powertrain Control Module (PCM). As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing PCM can cause a host of confusing and frustrating issues. This isn’t just a part; it’s the central command for your vehicle’s engine and transmission, and when it falters, everything is affected.
We offer a dependable and cost-effective solution. This is a genuine, used OEM PCM, part number 9355699, sourced from a salvaged vehicle and meticulously tested. The most significant benefit we provide is our professional programming service. Simply provide your vehicle’s VIN at checkout, and we will flash the module with the latest GM-certified software specific to your vehicle. This means it arrives at your door ready for installation, saving you a costly trip to the dealership for programming. It’s the smart way to get your vehicle back on the road without breaking the bank.
Case Study: A Tricky Diagnosis
A customer brought in a ’99 Suburban with a complaint that stumped two other shops: it would randomly stall at idle, but only when warm. There were no consistent trouble codes, just a history of random misfires. After checking fuel pressure, spark, and for vacuum leaks—all of which were fine—I hooked up my full-function scan tool to monitor live data. I noticed the injector pulse width would suddenly drop to zero right before a stall. This pointed away from mechanical issues and straight to the PCM. The internal processor was failing under heat soak. We installed a VIN-programmed PCM just like this one, performed the security relearn, and the stalling issue was completely resolved. It’s a classic example of how a faulty 1998 Envoy PCM can create phantom problems that are impossible to solve with just a wrench.
Is Your Vehicle Showing These Classic PCM Failure Signs?
- ✔ Check Engine Light is illuminated with codes like P0601, P0602, P0604, or P0606 (Internal Control Module Errors).
- ✔ The engine cranks but refuses to start.
- ✔ Poor fuel economy and engine performance.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Intermittent stalling or misfiring.
- ✔ Communication errors with your scan tool.
Your Straightforward PCM Installation Guide
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any electrical work.
- ✔ Locate the PCM: On most of these GM vehicles, the PCM is located in the engine compartment, often on the driver’s or passenger’s side fender well or near the battery. Refer to your vehicle’s service manual for the exact location.
- ✔ Disconnect Connectors: Carefully unclip and remove the large electrical harness connectors from the old PCM. These connectors have locking tabs that need to be released. Avoid forcing them.
- ✔ Remove the Old Module: Unbolt the old PCM from its mounting bracket. It’s typically held in by a few 10mm or 13mm bolts.
- ✔ Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten the bolts.
- ✔ Reconnect Everything: Firmly plug the electrical connectors into the new module until they click into place. Reconnect the negative battery terminal.
- ✔ Perform Security Relearn: You will likely need to perform a security or anti-theft relearn procedure (often called a CASE relearn). This can typically be done without special tools by cycling the key. A common method is: Turn the key to ‘ON’ for 10-15 minutes, then ‘OFF’ for 10 seconds. Repeat this cycle 3 times. The vehicle should then start.
Confirmed Fitment for a Wide Range of GM Vehicles
This module, identified by part number 9355699, is compatible with a vast array of GM trucks, vans, and SUVs. It directly replaces part numbers 16266645, 16250279, 16258815, 09366810, and 9366810. Please verify your vehicle is on the list below and that your original module carries one of these numbers for guaranteed compatibility. This is the correct 1998 Envoy PCM and fits many other models.
CHEVROLET 2500 PICKUP 98-99 (Gasoline)
CHEVROLET 3500 PICKUP 98-99 (Gasoline)
SUBURBAN 1500/2500 98-99 (Gasoline)
TAHOE 98-99 (Gasoline)
ASTRO 98
BLAZER S10 98 (w/o build date opt ZN4)
S10 PICKUP 98 (4.3L, w/o build date opt ZN4)
EXPRESS VAN 1500/2500/3500 98-99 (Gasoline)
CADILLAC ESCALADE 99
GMC 1500 PICKUP 98-99 (Gasoline)
GMC 2500 PICKUP 98-99 (Gasoline)
GMC 3500 PICKUP 98-99 (Gasoline)
YUKON 98-99
ENVOY 98 (w/o build date opt ZN4)
JIMMY S15 98 (w/o build date opt ZN4)
SONOMA 98 (4.3L, w/o build date opt ZN4)
SAFARI (GMC) 98
SAVANA VAN 1500/2500/3500 98-99 (Gasoline)
OLDSMOBILE BRAVADA 98 (w/o build date opt ZN4)
ISUZU HOMBRE 98 (4.3L, w/o build date opt ZN4)
By purchasing this pre-programmed 1998 Envoy PCM, you’re not just buying a part; you’re buying a complete, ready-to-install solution to get your vehicle running right again.
Do I need to do anything after installing this PCM?
Do I need to do anything after installing this PCM?
Yes. While we program the module to your VIN, you will need to perform a security relearn procedure (also known as a CASE relearn) after installation. This syncs the module to your vehicle’s anti-theft system and can usually be done without any special tools by cycling the ignition key. Instructions are included above.
How do I provide my VIN?
After you complete your purchase, you will need to send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot program and ship the module without it. Please double-check the VIN for accuracy before sending.
Is this a new part?
No, this is a high-quality, tested used part that has been sourced from a professionally salvaged vehicle. This allows us to provide a reliable, OEM-quality component at a fraction of the cost of a new module from the dealer.
Will this fix my vehicle’s problem?
This PCM will resolve issues directly caused by a faulty module. It’s crucial to properly diagnose your vehicle’s problem first. If you are experiencing symptoms like a no-start condition, internal module error codes (P0601, etc.), or erratic engine behavior with no other identifiable cause, a failing PCM is the likely culprit.