Restore Your Truck’s Brain and Get Back to Work
Is your trusty Chevy or GMC truck letting you down with baffling electrical gremlins? If you’re dealing with a no-start condition, random stalling, or a persistent check engine light that won’t go away, the Powertrain Control Module (PCM) is often the culprit. As the central computer for your engine and transmission, its health is critical. This isn’t just a replacement part; it’s a reliable, cost-effective solution. We are offering a genuine, used OEM PCM that has been professionally tested and programmed with the latest GM software updates specifically for your vehicle using your VIN. This ensures you’re not just replacing a part, but also benefiting from years of factory improvements for drivability and performance.
From the Diagnostic Bay
I remember a 1999 Suburban that came into the shop with a classic complaint: it would die randomly at stoplights, but always restart. The owner had already replaced the fuel pump and filter with no luck. A scan showed no hard codes, just a history of intermittent communication loss. On these GMT400 platform trucks, I’ve learned to check the PCM connections first, but they were clean. The issue was inside the module itself—a failing capacitor was causing voltage drops under certain thermal conditions. We swapped in a VIN-programmed PCM just like this one, performed the security relearn, and the stalling issue was gone for good. It’s a fix I’ve done hundreds of times, saving customers from chasing phantom fuel or ignition problems.
Is Your GM Truck or Van Showing These Signs?
A failing PCM can cause a wide range of frustrating symptoms. Before you start replacing expensive sensors or fuel system components, see if your vehicle is experiencing any of the following:
- ✔ Check Engine Light is on, often with codes like P0601 (Internal Control Module Memory Check Sum Error) or other communication faults.
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling, especially when coming to a stop or at idle.
- ✔ Poor or erratic automatic transmission shifting.
- ✔ A noticeable drop in fuel economy.
- ✔ Failure to pass an emissions or smog test.
- ✔ Gauges on the instrument cluster behaving erratically or not working at all.
Your Straightforward Installation Guide
Installing your pre-programmed 1998-1999 Chevrolet 3500 PCM is a job most DIYers can handle in their own driveway. Follow these steps carefully.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental contact.
- Locate the PCM: On most of these trucks and vans, the PCM is located in the engine compartment, typically on the driver’s side inner fender or near the battery.
- Disconnect the Old Module: Carefully unplug the wiring harness connectors. These connectors have locking tabs that need to be released. Do not force them.
- Remove the Old PCM: Unbolt the module from its mounting bracket. There are usually two or three bolts holding it in place.
- Install the New PCM: Mount your replacement module onto the bracket and securely plug in the wiring harness connectors. You should hear a click as they lock into place.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform Security Relearn: This is a critical step. Turn the key to the ‘ON’ position (without starting) for 10-15 minutes. The ‘Security’ light should turn off. Turn the key off for 10 seconds, then the vehicle should start and run normally. This may need to be repeated up to 3 times.
Verified Fitment for Your GM Vehicle
This module, identified by part number 9355699, is a direct replacement for a wide range of GM vehicles. Please verify your original part number or match your vehicle from the list below. This part is compatible with service numbers 09355699, 16266645, 16250279, 16258815, 09366810, and 9366810.
CHEVROLET/GMC SUBURBAN 1500/2500 (1998-1999, Gasoline)
CHEVROLET TAHOE / GMC YUKON (1998-1999, Gasoline)
CADILLAC ESCALADE (1999)
CHEVROLET EXPRESS / GMC SAVANA 1500/2500/3500 VAN (1998-1999, Gasoline)
CHEVROLET ASTRO / GMC SAFARI (1998)
CHEVROLET S10 / GMC SONOMA (1998, 4.3L)
CHEVROLET BLAZER / GMC JIMMY (1998, 4.3L)
OLDSMOBILE BRAVADA (1998)
GMC ENVOY (1998)
ISUZU HOMBRE (1998, 4.3L)
Note: Please match the ID number 9355699 from your original module to ensure compatibility.
Why do you need my VIN?
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to program the PCM with the exact software and calibrations your vehicle requires. This includes specifications for the engine, transmission, and any factory options. It ensures a seamless, plug-and-play installation without needing a trip to the dealer.
Is this a new part?
No, this is a high-quality, tested, and guaranteed used OEM part sourced from a salvaged vehicle. This provides the reliability of a genuine GM part at a fraction of the cost of a new one.
What is the security relearn procedure?
The security relearn (or Passlock relearn) syncs the replacement PCM with your vehicle’s anti-theft system. The procedure is outlined in the installation steps above and is essential for allowing the engine to start and run after the PCM is replaced.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls the transmission shift points and line pressure. If your shifting issues are caused by a faulty module, this replacement 1998-1999 Chevrolet 3500 PCM, programmed with the latest GM software, can resolve them. However, mechanical issues within the transmission will not be fixed by a PCM replacement.