Restore Peak Performance to Your GM Truck or SUV
Is your 1999-2000 Chevrolet Tahoe, Suburban, or other GM vehicle running rough, stalling unexpectedly, or showing a persistent Check Engine Light? As a technician with over two decades of experience, I’ve seen countless drivers chase expensive, unnecessary repairs when the real culprit is a failing Powertrain Control Module (PCM). This isn’t just a part; it’s the brain of your vehicle’s engine and transmission. When it falters, you get frustrating, hard-to-diagnose problems. This module is the direct, reliable solution to get your truck back on the road and running smoothly.
This isn’t a generic, one-size-fits-all computer. We take your vehicle’s unique Vehicle Identification Number (VIN) and program this PCM with the very latest GM factory software. This ensures it communicates perfectly with your specific engine, transmission, and options, restoring the original fuel efficiency, shifting strategy, and engine performance. It’s a plug-and-play fix that eliminates the need for a costly trip to the dealership for programming.
From the Diagnostic Bay: The Case of the Intermittent Stall
A customer brought in his ’99 Yukon with a problem that had stumped two other shops: it would randomly stall at stoplights, but only after it was fully warmed up. There were no consistent trouble codes, just a history of random misfires. We checked fuel pressure, ignition components, and sensors—all were fine. Drawing on experience, I suspected the PCM. On these older GM trucks, I’ve seen the internal driver circuits for the ignition or fuel injectors fail under heat. The solder joints get brittle over 20+ years of heat cycles. We connected a lab scope to monitor the injector pulse and, sure enough, after 30 minutes of idling, the signal would drop out just before it stalled. Swapping in a correctly programmed PCM like this one solved the problem instantly. The customer went from being ready to sell the truck to having his reliable workhorse back.
Is Your Vehicle Showing These Symptoms?
A failing PCM can cause a wide range of issues. If you’re experiencing any of the following, a faulty engine computer is a likely cause:
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (ECM/PCM Processor Fault).
- ✔ The engine cranks but refuses to start.
- ✔ Harsh, erratic, or delayed transmission shifting.
- ✔ A noticeable drop in fuel economy.
- ✔ The vehicle stalls for no apparent reason, especially when warm.
- ✔ Failure to pass an emissions/smog test.
- ✔ Communication errors with diagnostic scan tools.
A Straightforward Guide to Installation
Replacing your 1999-2000 Tahoe PCM is a job most DIYers can handle in their own driveway. Follow these steps for a smooth installation.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental reconnection.
- Locate the PCM: On most of these trucks and SUVs, the PCM is located in the engine compartment, typically on the driver’s side inner fender or near the battery. On vans, it’s often in the LH rear of the engine compartment.
- Disconnect the Connectors: Carefully unclip and remove the electrical wiring harnesses from the old PCM. These connectors have locking tabs that may need to be gently pried up. Inspect the terminals for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. There are typically 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 original bolts.
- Reconnect Everything: Firmly plug the wiring harnesses into the new module until they click into place. Reconnect the negative battery terminal.
- Security Relearn Procedure: In many cases, you will need to perform a simple security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows the vehicle’s anti-theft system to recognize the new PCM. Your vehicle will not start until this is completed.
Verified Vehicle Compatibility
This module is a direct-fit replacement for a wide range of GM vehicles. Please verify your part number (16263494, 16265035) and vehicle in the list below to ensure proper fitment. This list is a guide; providing your VIN for programming is the best way to guarantee compatibility.
CHEVROLET 3500 PICKUP 99-00
TAHOE 99-00 (Classic Style)
SUBURBAN 1500/2500 99
GMC 1500/2500/3500 PICKUP 99-00
SIERRA/SILVERADO 1500 99-00 (6 cyl)
YUKON / YUKON DENALI 99-00
ESCALADE 99-00
EXPRESS VAN 1500/2500/3500 99-02
SAVANA VAN 1500/2500/3500 99-02
ASTRO / SAFARI 99-01
BLAZER / JIMMY S10/S15 98-00
S10 / SONOMA 98-00 (4.3L)
BRAVADA 98-00
ENVOY 98-00
ISUZU HOMBRE 98-00 (4.3L)
Note: Some 1998 models require build date option ZN4. Always match your part number.
Frequently Asked Questions
How does the VIN programming process work?
After you complete your purchase, you will need to provide us with your 17-digit VIN. Our technicians use this number to access the official GM software database and load the exact calibration file for your vehicle’s specific configuration. This ensures perfect operation right out of the box.
Is this a simple plug-and-play installation?
Yes, for the most part. The module is a direct physical replacement and comes programmed. However, as with any PCM replacement on these GM vehicles, you must perform the security relearn procedure after installation. It’s a simple process that takes about 30 minutes and requires no special tools.
What is the difference between a PCM, ECM, and ECU?
The terms are often used interchangeably. ECM (Engine Control Module) typically just controls engine functions. PCM (Powertrain Control Module) controls both the engine and the automatic transmission. ECU (Electronic Control Unit) is a more generic term. For your 1999-2000 Tahoe PCM, this module manages the entire powertrain.
Will this fix my specific problem?
This module corrects issues directly caused by a faulty computer. While it solves a vast majority of the symptoms listed above, we always recommend proper vehicle diagnostics to confirm the PCM is the point of failure before ordering. A bad sensor or wiring issue can sometimes mimic PCM failure.
Do I need to send my old part back?
No core charge is required for this part. You do not need to return your old, faulty module to us.