Restore Peak Performance to Your GM Truck or Van
Is your trusty 1998 Chevy Astro, Express van, or GMC Sierra acting up? If you’re dealing with a persistent Check Engine Light, rough idling, poor fuel mileage, or even a frustrating no-start condition, the heart of the problem is often a failing Powertrain Control Module (PCM). As an experienced technician, I’ve seen firsthand how a faulty PCM can mimic a dozen other issues, leading to wasted time and money on unnecessary parts. This isn’t just a component; it’s the brain of your engine, and when it falters, your vehicle’s reliability and performance suffer.
We offer a dependable and cost-effective solution: a thoroughly tested, used OEM 1998 Astro PCM that is professionally programmed to your vehicle’s specific Vehicle Identification Number (VIN). This critical programming step ensures that the computer has the latest software updates from General Motors and communicates flawlessly with your vehicle’s systems right out of the box. Forget expensive trips to the dealership for programming—we handle it for you before it ships.
A Technician’s Notebook: The Misleading No-Start
I remember a 1999 Suburban that was towed into my bay. The owner had already replaced the fuel pump and filter, convinced it was a fuel delivery problem. The engine would crank but never fire. A quick scan showed no communication with the PCM. Instead of throwing more parts at it, we checked the power and grounds at the PCM connectors—they were solid. The issue was internal to the module itself. A replacement, programmed PCM like this one had the truck running perfectly in under 30 minutes. It’s a classic case where diagnosing the ‘brain’ first saves hundreds of dollars.
Is Your GM Vehicle Showing These Symptoms?
A failing engine computer can cause a wide range of problems. If you’re experiencing any of the following, a faulty PCM could be the culprit:
- ✔ Persistent Check Engine Light (CEL)
- ✔ Stored diagnostic trouble codes (DTCs) like P0601 (Internal Control Module Memory Check Sum Error) or P0605 (Internal Control Module Read Only Memory (ROM) Error)
- ✔ Engine cranks but will not start
- ✔ Rough or unstable idle
- ✔ Noticeable decrease in fuel economy
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Failure to pass an emissions inspection
Your Straightforward Installation Guide
Installing your programmed 1998 Astro PCM is a manageable job for a DIYer with basic tools. Follow these steps carefully for a successful replacement.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent any accidental reconnection.
- Locate the PCM: On most of these GM trucks and vans, the PCM is located in the engine compartment, often on the driver’s side fender, near the battery or airbox.
- Disconnect the Connectors: Carefully unclip and remove the electrical wiring harnesses from the old PCM. These connectors have locking tabs that need to be released. Avoid forcing them.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. There are typically a few bolts holding it in place.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten the bolts.
- Reconnect Everything: Plug the wiring harnesses firmly into the new PCM until they click into place. Reconnect the negative battery terminal.
- Perform Security Relearn: Your vehicle is equipped with a Passlock/VATS security system. You will need to perform a security relearn procedure. This 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 should then start.
Verified Compatibility for Your Vehicle
This module is a direct replacement for part numbers 16266645, 09355699, 9355699, 16250279, 16258815, 09366810, and 9366810. It is guaranteed to fit the following vehicles with service ID 9355699:
- 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline)
- 1998-1999 Chevrolet Suburban & GMC Suburban 1500, 2500 (Gasoline)
- 1998-1999 Chevrolet Tahoe & GMC Yukon (Gasoline)
- 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans (Gasoline)
- 1998 Chevrolet Astro & GMC Safari
- 1998 Oldsmobile Bravada (w/o build date opt ZN4)
- 1998 Chevrolet S10 & GMC Sonoma (4.3L, w/o build date opt ZN4)
- 1998 Chevrolet Blazer & GMC Jimmy (w/o build date opt ZN4)
- 1998 GMC Envoy (w/o build date opt ZN4)
- 1999 Cadillac Escalade
- 1998 Isuzu Hombre (4.3L, w/o extended build date opt ZN4)
Do I need to do any programming to this PCM?
Do I need to do any programming to this PCM?
No. We program the computer for you using your vehicle’s VIN before we ship it. This ensures it has the latest GM software and is ready for installation, saving you a trip to the dealer.
Where do I provide my VIN?
After you complete your purchase, you will need to send us a message with your 17-digit VIN. We cannot ship the part until we receive this information for programming.
What is the security relearn procedure?
This is a required step to sync the new PCM with your vehicle’s anti-theft system. It’s a simple process you can do yourself with just the ignition key and about 30 minutes of time. Instructions are widely available online for your specific model, or you can consult your owner’s manual.
Is this a new part?
No, this is a high-quality, tested used OEM part that has been sourced from a salvaged vehicle. This provides OEM reliability at a fraction of the cost of a new dealer part.
How do I confirm this part fits my vehicle?
The best way is to match the part number from your existing computer. Look for a sticker on your current PCM and match it to one of the numbers listed, such as 16266645 or 09355699. You can also use our detailed fitment list.