Restore Your Truck’s Performance and Reliability
Is your 1998 or 1999 Chevy or GMC truck giving you headaches? A faulty Powertrain Control Module (PCM), the vehicle’s central computer, is often the culprit behind a host of frustrating issues. From a persistent check engine light to erratic engine behavior or transmission problems, a failing PCM can bring your workhorse to a standstill. This isn’t just an inconvenience; it affects your fuel economy, emissions, and overall driving safety. As a technician with over two decades of experience, I’ve seen countless vehicles sidelined by simple electronic failures that seem complex at first glance.
This is your straightforward, reliable solution. We offer a genuine, used GM PCM with service number 9355699. The real value here is our professional programming service. Before we ship it, we flash the module with the latest official GM software updates, specifically matched to your truck using your Vehicle Identification Number (VIN). This means it arrives at your door ready to install, eliminating the need for expensive dealership programming or specialized scan tools. You get a dependable part that restores factory performance without the dealership price tag.
Case Study: A Tricky Diagnosis
I remember a ’99 Suburban that came into my bay with an intermittent no-start condition that had stumped two other shops. They had replaced the fuel pump and the ignition coil, but the problem persisted. The owner was frustrated and ready to sell the truck. After hooking up my diagnostic scanner, I noticed the 5-volt reference signal to the sensors would occasionally drop out right before it would stall. This wasn’t a sensor issue; it was the PCM’s internal voltage regulator failing under heat. We installed one of these VIN-programmed PCMs, and the truck fired up instantly and ran perfectly. It’s a classic example of how the 1998-1999 Chevrolet 1500 PCM can be the root cause of seemingly unrelated problems.
Is Your GM Truck Showing These Signs?
A failing PCM can manifest in various ways. If you’re experiencing any of the following, this module is likely the solution you need. Look out for:
- ✔ Persistent Check Engine Light with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0605 (Internal Control Module Read Only Memory (ROM) Error).
- ✔ Engine stalling, stumbling, or running rough for no apparent reason.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Complete no-start condition where the engine cranks but won’t fire.
- ✔ A noticeable decrease in fuel efficiency.
- ✔ Failure to pass a state emissions inspection.
- ✔ Communication errors with diagnostic scan tools.
A Straightforward Guide to Installation
Replacing the PCM on these GM trucks is a job most DIYers can handle in under an hour with basic hand tools. Follow these steps for a smooth installation:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow the system to fully discharge.
- Locate the PCM: On most of these trucks and vans, the PCM is located in the engine bay, typically on the driver’s side inner fender or near the battery. It’s a silver metal box with several large wiring harness connectors.
- Disconnect the Harnesses: Carefully release the locking tabs on each electrical connector and pull them straight out from the module. Avoid pulling on the wires themselves. Some connectors may have a lever or clip that needs to be pivoted to release.
- 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 PCM: Mount your new, pre-programmed PCM onto the bracket and secure it with the original bolts.
- Reconnect Everything: Firmly plug the wiring harnesses back into the correct sockets on the new module. You’ll hear a click as they lock into place. Reconnect the negative battery terminal.
- Final Steps: Your vehicle may require a security relearn procedure (often called Passlock or Passkey) to allow the engine to start. This procedure is simple and typically involves turning the key to the ‘ON’ position for 10-15 minutes. Instructions for this are widely available online for your specific model. The engine is now ready to start.
Verified Vehicle Compatibility
This module, identified by service number 9355699, is a direct-fit replacement for a wide range of GM vehicles. Please match your original part number or use the fitment list below to confirm compatibility. This part is interchangeable with numbers: 09355699, 16266645, 16250279, 16258815, 09366810, 9366810.
This part fits many 1998-1999 GM Trucks, Vans, and SUVs including:
- ✔ Chevrolet & GMC 1500/2500/3500 Pickups (Gasoline)
- ✔ Chevrolet Tahoe & GMC Yukon (Gasoline)
- ✔ Chevrolet & GMC Suburban 1500/2500 (Gasoline)
- ✔ Chevrolet Express & GMC Savana 1500/2500/3500 Vans (Gasoline)
- ✔ Cadillac Escalade
- ✔ Chevrolet Astro & GMC Safari
- ✔ Oldsmobile Bravada, Chevrolet S10 Blazer, GMC S15 Jimmy, Isuzu Hombre (4.3L V6 models)
Note: It is critical to match the service number 9355699 from your original module to ensure proper function.
Why do you need my VIN?
Why do you need my VIN?
Your VIN (Vehicle Identification Number) allows us to program the PCM with the exact software and calibrations your specific vehicle requires. This includes engine size, transmission type, gear ratios, and any other factory options. This ensures the module works perfectly right out of the box.
Is this a new part?
No, this is a high-quality, tested, and fully functional used OEM (Original Equipment Manufacturer) part that has been sourced from a salvaged vehicle. We inspect and program it to ensure it meets or exceeds original factory standards for performance.
Will I need to do anything else after installation?
In most cases, you will need to perform a security relearn procedure, which syncs the new PCM with your vehicle’s anti-theft system. This is a simple process that does not require special tools. On some models, a Crankshaft Position Sensor (CASE) relearn may be beneficial and can be done by most local repair shops if needed.
What is the difference between a PCM and an ECM?
The terms are often used interchangeably. ECM (Engine Control Module) typically controls only engine functions. A PCM (Powertrain Control Module) is more integrated and controls both the engine and the automatic transmission. This part is a PCM.