Restore Peak Performance to Your GM Vehicle
Is your 1998-1999 Chevy Astro or GMC Safari van running rough, shifting erratically, or failing to start? As a technician with over two decades of experience, I’ve seen these symptoms countless times, and they often point directly to a failing Powertrain Control Module (PCM). This isn’t just a part; it’s the central computer for your engine and transmission. When it falters, the entire vehicle suffers. This replacement PCM is your direct, reliable solution to get your trusted van or truck back on the road, running just as it should.
We take the guesswork and dealer-level expense out of the equation. Unlike a generic part from a salvage yard, this module comes fully programmed with the latest official GM software updates, specifically matched to your vehicle using your VIN. This ensures seamless communication between all your vehicle’s systems, from the fuel injectors to the transmission solenoids. A properly functioning 1998-1999 Astro Powertrain Control Module is critical for optimal fuel economy, smooth shifting, and dependable engine operation.
From the Diagnostic Bay
I remember a 1998 GMC Safari that came into the shop with a ghost of a problem. The owner said it would randomly stall at stoplights, but never threw a consistent Check Engine Light. We checked fuel pressure, ignition components, and sensors—all tested fine. After hours of diagnostics, we hooked up a high-end scanner and monitored the PCM data stream. We noticed the voltage reference signal would flicker and drop out just before a stall. It was a classic case of internal PCM failure due to heat cycles and age. We swapped in a VIN-programmed module just like this one, and the van ran flawlessly. It’s a reminder that sometimes the most confusing problems have a straightforward, central solution.
Is Your Vehicle Showing These Signs of PCM Failure?
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0605 (Internal Control Module Read Only Memory (ROM) Error).
- ✔ The engine cranks but refuses to start, or starts and immediately stalls.
- ✔ Noticeable decrease in fuel mileage for no apparent reason.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ The vehicle runs poorly, with misfires, hesitation, or stumbling.
- ✔ Communication errors with your scan tool.
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- ✔ Locate the PCM: On the 1998-1999 Astro and Safari vans, the PCM is conveniently located in the engine compartment on the driver’s side, near the battery and coolant overflow tank.
- ✔ Disconnect the Harnesses: Carefully unclip and disconnect the electrical wiring harnesses from the old module. These connectors have locking tabs that need to be released before pulling.
- ✔ Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware, as you may need it for the new module.
- ✔ Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and securely reconnect the wiring harnesses. Ensure they click into place.
- ✔ Reconnect and Start: Reconnect the negative battery terminal. Your vehicle is now ready to start. In some cases, a security relearn procedure may be necessary, which typically involves turning the key to the ‘On’ position for 10-15 minutes.
Verified Vehicle Compatibility
This 1998-1999 Astro Powertrain Control Module is a direct-fit replacement for a wide range of GM trucks and vans. Please verify your part number or match your vehicle from the list below. This unit is compatible with service numbers 16250279, 09366810, and 09355699.
- ASTRO / SAFARI (GMC)
- BLAZER S10 / JIMMY S15 / S10 / S15 / SONOMA
- BRAVADA / ENVOY
- CHEVROLET / GMC PICKUP (1500, 2500, 3500 – Gasoline)
- SUBURBAN (1500, 2500 – Gasoline)
- TAHOE / YUKON
- EXPRESS / SAVANA VAN (1500, 2500, 3500 – Gasoline)
- CADILLAC ESCALADE (1999)
- ISUZU HOMBRE (1998, 4.3L)
Note: For some 1998 S-platform models (Blazer, Jimmy, etc.), please check for build date option ZN4. This module fits vehicles without this option.
Do I need to get this programmed by a dealer?
No. We program the module to your vehicle’s specific VIN before shipping it to you. It arrives ready for installation, saving you a trip to the dealership and additional programming fees.
Where is the PCM located on my 1999 Astro van?
On the Chevrolet Astro and GMC Safari, you’ll find the PCM in the engine bay on the driver’s side, mounted near the battery.
What information do you need from me?
After you place your order, we will need your 17-digit Vehicle Identification Number (VIN). This allows us to load the correct GM-certified software for your specific engine, transmission, and options.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the PCM (like codes P0601 or P0605), then yes, this will resolve the issue. It’s always best to have your vehicle properly diagnosed to confirm the PCM is the root cause.
Is this part the same as an ECM?
Yes. The terms Powertrain Control Module (PCM) and Engine Control Module (ECM) are often used interchangeably for this component, as it controls both engine and transmission functions in these vehicles.