Restore Your Truck’s Brainpower and Get Back on the Road
As a mechanic with over two decades of experience under the hood, I’ve seen firsthand the frustration a failing Powertrain Control Module (PCM) can cause. Your 1998-1999 Chevrolet 3500 Pickup is a workhorse, but when its ‘brain’ starts to glitch, you get baffling problems: stalling for no reason, poor fuel economy, erratic shifting, or a persistent Check Engine Light that won’t go away. This isn’t just an annoyance; it’s a reliability issue that can leave you stranded. This quality-tested, used OEM PCM, part number 09355699, is the dependable, cost-effective solution you’ve been looking for.
What sets this module apart is our essential pre-programming service. Before this PCM even leaves our facility, we flash it with the latest GM software updates and program it specifically to your vehicle’s VIN. This critical step ensures that when it arrives, it’s ready for installation, saving you the significant time, cost, and hassle of a trip to the dealership for programming. You get a component that communicates flawlessly with your truck’s engine, transmission, and other systems right out of the box.
A Technician’s Notebook
I remember a 1999 GMC Suburban that came into the shop with a ghost of a problem. The owner complained of intermittent stalling at stoplights and a harsh 1-2 shift that came and went. We checked everything—fuel pressure was solid, the throttle body was clean, and the transmission fluid was perfect. No consistent codes were stored, just a few random misfire counts. After verifying all power and ground circuits to the engine computer were solid, we decided to swap in a known-good PCM. The difference was immediate. The engine idled smoothly, the transmission shifted like new, and the stalling issue was gone. The original PCM had an internal intermittent fault that was impossible to see on a standard scan tool. This is a classic scenario where replacing the 1998-1999 Chevrolet 3500 PCM (or in that case, the Suburban’s identical unit) was the only correct fix.
Is Your Truck Showing These PCM Failure Signs?
- ✔ Check Engine Light: A constant Check Engine Light with codes like P0601 (Internal Control Module Memory Check Sum Error) or other P06xx codes points directly to a faulty computer.
- ✔ No-Start or Hard Starting: The engine cranks but won’t start, or takes an excessively long time to fire up, often due to the PCM not firing the injectors or coils correctly.
- ✔ Erratic Engine Performance: Unexplained stalling, rough idling, engine misfires, or a sudden drop in fuel efficiency are classic symptoms.
- ✔ Poor Shifting or Transmission Problems: The PCM plays a major role in controlling automatic transmission shift points. Harsh shifting, getting stuck in a gear (limp mode), or delayed engagement can be caused by a failing module.
- ✔ Failed Emissions Test: A malfunctioning PCM can’t properly manage the engine’s fuel and emissions systems, leading to an automatic failure at the inspection station.
Your Straightforward Installation Guide
Installing your programmed 1998-1999 Chevrolet 3500 PCM is a manageable job for a DIYer with basic tools. Follow these steps carefully for a smooth replacement.
- Safety First: Always disconnect the negative terminal from your truck’s battery and secure it away from the post 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 firewall.
- Disconnect the 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 pulling on the wires themselves.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. There are usually two or three bolts holding it in place.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and secure it with the bolts.
- Reconnect Everything: Firmly plug the electrical connectors into the new PCM until they click and lock into place. Reconnect the negative battery terminal.
- Perform Security Relearn (If Necessary): In some cases, a simple security relearn procedure is needed. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’ for 10 seconds, and repeating two more times. Your truck should then start normally.
Verified Compatibility for Your GM Truck or Van
This module is a direct replacement for service number 09355699 and is interchangeable with part numbers 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. It is confirmed to fit the following vehicles (gasoline engines unless specified):
- Chevrolet/GMC Pickups (1500, 2500, 3500): 1998-1999
- Chevrolet/GMC Suburban (1500, 2500): 1998-1999
- Chevrolet Tahoe / GMC Yukon: 1998-1999
- Cadillac Escalade: 1999
- Chevrolet Express / GMC Savana Vans (1500, 2500, 3500): 1998-1999
- Chevrolet Astro / GMC Safari: 1998
- Chevrolet S10 / GMC Sonoma (4.3L): 1998
- Chevrolet Blazer / GMC Jimmy (4.3L): 1998
- Oldsmobile Bravada (4.3L): 1998
- Isuzu Hombre (4.3L): 1998
This is a reliable, tested component pulled from a salvaged vehicle, offering OEM quality without the new-part price tag. By providing your VIN, you ensure this 1998-1999 Chevrolet 3500 PCM arrives ready to solve your truck’s problems and restore its performance.
Frequently Asked Questions
Why do you need my Vehicle Identification Number (VIN)?
Your VIN is essential. It allows us to access the specific GM database for your truck’s year, model, engine, transmission, and emissions equipment. We use this to load the correct factory software and the latest updates, ensuring the PCM works perfectly with your vehicle’s systems right out of the box.
Is any other programming required after installation?
In most cases, no. Because we program the module to your VIN before shipping, it’s ready to go. Some vehicles may require a simple ‘security relearn’ procedure, which takes about 30 minutes and involves cycling the ignition key. This does not require any special tools.
My old part number isn’t an exact match, but it’s on the cross-reference list. Will this work?
Yes. Manufacturers often use several part numbers for the same component over its production life. As long as your original part number is on our compatibility list, this module is the correct replacement. We program it to function for your specific vehicle.
What’s the difference between a PCM and an ECM?
The terms are often used interchangeably. ECM stands for Engine Control Module, while PCM means Powertrain Control Module. In most modern vehicles like your Chevy truck, the module controls both the engine and the transmission, making ‘PCM’ the more accurate term. For all practical purposes in this context, they refer to the same part.