Restore Your GM Truck’s Performance and Reliability
Is your trusty 1998-1999 Chevrolet Suburban, Tahoe, or GMC truck plagued by frustrating issues like a persistent check engine light, rough idling, stalling, or erratic shifting? Before you consider costly and complex repairs, the root cause is often a failing Powertrain Control Module (PCM). As the central computer of your vehicle, the PCM manages everything from fuel mixture and spark timing to transmission shift points. When it falters, the symptoms can be widespread and confusing. This tested, used PCM is the straightforward, reliable solution to get your truck running properly again.
We take the guesswork and dealer expense out of the equation. Each module is meticulously programmed with the latest official GM software updates, specifically tailored to your vehicle’s Vehicle Identification Number (VIN). This means you receive a part that’s ready for installation right out of the box, eliminating the need for expensive dealership programming or specialized scan tools. It’s the most efficient way to solve complex electronic issues and restore the dependable performance you rely on.
A Technician’s Notebook
I remember a ’99 Yukon that came into the shop with a complaint of intermittent stalling and a transmission that would randomly refuse to shift out of first gear. The owner had already replaced the throttle position sensor and the mass air flow sensor with no luck. There were no hard codes, just a history of communication loss faults. After checking the wiring harness for damage, we focused on the PCM. On these GMT400 platforms, the PCM can develop internal faults that don’t always throw a specific P0601 ‘Internal Controller Failure’ code right away. Instead, they manifest as bizarre electrical gremlins. We swapped in a pre-programmed PCM like this one, performed the security relearn, and the truck ran perfectly. It’s a fix I’ve performed hundreds of times on these reliable but aging trucks.
Common Signs of a Failing PCM
If your vehicle is experiencing any of the following, a faulty PCM could be the culprit. A failing module can cause one or more of these symptoms, which may be intermittent at first.
- ✔ Check Engine Light is on with codes like P0601, P0605, or other communication errors.
- ✔ Engine stalls for no apparent reason or has trouble starting.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine misfires, runs rough, or hesitates on acceleration.
- ✔ The vehicle won’t start at all, and the security light may be flashing.
A Straightforward Guide to Installation
Installing your programmed 1998-1999 Suburban 1500 PCM is a manageable job for a DIYer with basic tools. The most important part is the security relearn procedure, which can be done without a scan tool.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- 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 Connectors: Carefully unlatch and remove the electrical connectors from the old PCM. There are usually three large multi-pin connectors. Inspect them for any corrosion or damaged pins.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely reconnect the electrical connectors. Ensure they click into place.
- Reconnect Battery: Re-attach the negative battery terminal.
- Perform Security Relearn (CRITICAL STEP): Do not attempt to start the engine yet. You must perform the Passlock/VATS security relearn procedure. It typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’ for 10 seconds, and repeating this cycle three times. Your vehicle’s specific procedure can be easily found online. The engine will not start until this is completed.
Will This Fit My GM Truck or Van?
This PCM is a direct replacement for service number 16266645 and interchanges with several other part numbers including 09355699, 16250279, 16258815, and 09366810. It is guaranteed to fit the following vehicles, provided the service number on your original module matches:
- ✔ 1998-1999 Chevrolet & GMC Suburban 1500/2500 (Gasoline)
- ✔ 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline)
- ✔ 1998-1999 Chevrolet Tahoe & GMC Yukon (Gasoline)
- ✔ 1999 Cadillac Escalade
- ✔ 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans (Gasoline)
- ✔ 1998 Chevrolet Astro & GMC Safari
- ✔ 1998 Chevrolet S10, GMC Sonoma, Blazer, Jimmy, Oldsmobile Bravada, Isuzu Hombre (4.3L V6)
- ✔ 1998 Oldsmobile Bravada & GMC Envoy
Note: It is essential to provide your VIN upon purchase so we can program the module correctly for your vehicle’s specific options and ensure full compatibility.
Frequently Asked Questions
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 had from the factory, plus any available GM updates. This ensures proper engine, transmission, and emissions system operation without a trip to the dealer.
Is this a new part?
No, this is a high-quality, tested used part sourced from a salvaged vehicle. Each unit is inspected and verified to be fully functional before being programmed and shipped. This provides a reliable and cost-effective solution.
What is a security relearn and is it difficult?
A security relearn (also called VATS or Passlock relearn) syncs the new PCM to your vehicle’s anti-theft system. It’s a simple, tool-free procedure that usually takes about 30 minutes and involves cycling the ignition key. We recommend looking up the exact steps for your model year before you begin installation.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the original PCM (common codes P0601-P0606) or a software issue, this part will resolve the problem. However, if the light is on due to a faulty sensor or other component, that part will still need to be repaired.
Does this 1998-1999 Suburban 1500 PCM require any other programming?
No. Our service includes programming the module to your VIN. The only remaining step for you is the security relearn procedure after installation. In some cases, a Crankshaft Variation (CASE) relearn may be needed with a scan tool to optimize misfire detection, but the vehicle will run and drive without it.