Restore Your Truck’s Brain and Get Back to Work
If you’re dealing with a frustrating check engine light, poor fuel mileage, erratic shifting, or a no-start condition in your GM truck or van, the problem often points directly to a failing Powertrain Control Module (PCM). As a technician with over 20 years of experience, I’ve seen how a faulty PCM can cause a cascade of confusing issues. It’s the central computer of your vehicle, and when it starts to fail, your truck’s reliability disappears. This isn’t just an inconvenience; it’s a problem that can leave you stranded.
This isn’t just a replacement part; it’s a complete solution. We take the guesswork and dealership hassle out of the equation. Before this module ships, we program it with the latest GM-approved software updates using the unique Vehicle Identification Number (VIN) from your truck. This ensures that when it arrives, it’s ready for a straightforward installation, correcting known factory bugs and optimizing engine and transmission performance. Getting a reliable, correctly programmed 1999 GMC 1500 PCM is the most critical step to resolving complex electronic issues and restoring your vehicle’s dependability.
Case Study: A Tricky Diagnosis
I remember a 2000 Chevy Express van that came into the shop with an intermittent stalling problem that no one could figure out. It would run fine for days, then suddenly die at a stoplight. The owner had already replaced the fuel pump and ignition control module. After scanning, we found no hard codes, just a history of communication loss faults. We checked all the main power and ground connections to the PCM—they were solid. On a hunch, we connected a scope and monitored the 5-volt reference signal. During a long test drive, we saw the voltage dip erratically just before it stalled. This pointed to an internal failure in the PCM. We installed one of these VIN-programmed modules, performed the security relearn, and the van never had the issue again. It’s a classic example of how a failing PCM can mimic other component failures.
Is Your GM Truck Showing These Telltale Signs?
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, a replacement module is the likely solution. Watch for these common indicators:
- ✔ Check Engine Light is on with codes like P0601 (Internal Memory Failure) or P0606 (PCM Processor Fault).
- ✔ The engine cranks but refuses to start.
- ✔ Noticeable decrease in fuel economy.
- ✔ The transmission shifts harshly, late, or not at all.
- ✔ The engine runs rough, misfires, or stalls intermittently.
- ✔ Failure to pass an emissions/smog test.
A Straightforward Guide to Installation
Replacing the PCM is a job most DIYers can handle with basic tools. Because this module comes programmed, you can avoid a costly trip to the dealer. While a security relearn procedure may be necessary, it can typically be done without special tools.
- 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, often on the driver’s side fender or near the battery.
- Disconnect the Connectors: Carefully unclip and remove the electrical wiring harnesses from the old module. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket.
- Install the New Module: Mount your new, pre-programmed PCM and securely reconnect the wiring harnesses.
- Reconnect Battery: Reattach the negative battery terminal.
- Perform Security Relearn: You may need to perform a security relearn procedure (often called a CASE learn or Passlock relearn). This typically involves a sequence of turning the key to the ‘ON’ and ‘OFF’ positions. Instructions for this are widely available online for your specific model.
Guaranteed Fitment for Your GM Vehicle
This module is a direct replacement for a wide range of GM vehicles. Please verify your vehicle is on this list and that your original part number matches one of the compatible numbers below to ensure a perfect fit. This module is compatible with part numbers: 16263494, 16265035, 8162634940, 218-11787, 21811787.
BLAZER/JIMMY S-SERIES: 98 (w/build date opt ZN4), 99-00
BRAVADA: 98 (w/build date opt ZN4), 99-00
ENVOY: 98 (w/build date opt ZN4), 99-00
CHEVROLET/GMC 1500 PICKUP: 99 (5.0L/5.7L, ID 16263494)
SIERRA/SILVERADO 1500 PICKUP: 99-00 (4.3L 6-cyl)
CHEVROLET/GMC 2500 PICKUP: 99 (gas, ID 16263494), 00 (gas)
CHEVROLET/GMC 3500 PICKUP: 99 (gas, ID 16263494), 00 (gas)
ESCALADE: 99 (ID 16263494), 00
EXPRESS/SAVANA 1500 VAN: 99-02 (ID 16263494)
EXPRESS/SAVANA 2500 VAN: 99-02 (gas, ID 16263494)
EXPRESS/SAVANA 3500 VAN: 99-02 (gas, ID 16263494)
ISUZU HOMBRE: 98 (4.3L, w/opt ZN4), 99-00 (4.3L)
SAFARI (GMC): 99-01 (ID 16263494)
S10/S15/SONOMA: 98 (4.3L, w/opt ZN4), 99-00 (4.3L)
SUBURBAN 1500/2500: 99 (gas, ID 16263494)
TAHOE/YUKON: 99 (gas, ID 16263494), 00 (Classic/Denali)
Frequently Asked Questions
What information do you need to program the PCM?
After you complete your purchase, you must provide us with your vehicle’s 17-digit VIN. This allows us to flash the module with the correct software and the latest updates from GM for your specific vehicle.
Is this a simple plug-and-play installation?
For the most part, yes. Because it comes pre-programmed to your VIN, you will not need a dealer-level scan tool for programming. However, on many GM vehicles, you will need to perform a security relearn procedure after installation to sync the module with your vehicle’s anti-theft system. This can usually be done in your driveway.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM also controls transmission functions, including shift points and line pressure. If your shifting problems are caused by faulty electronic commands from the module, this new PCM will resolve them.
Do I need to return my old PCM?
This listing does not require a core return. You can keep your old part.
Is the part number important if you’re programming by VIN?
Yes. While VIN programming ensures the correct software, matching the hardware (part number) is crucial for ensuring all physical connections and internal components are correct for your vehicle’s specific systems. Please cross-reference your original part number.