If you’re dealing with a 1998 GMC Safari or another classic GM truck that’s giving you headaches—stalling, running rough, or refusing to start—the Powertrain Control Module (PCM) is often the culprit. As a technician with over two decades of experience, I’ve seen how a failing PCM can mimic a dozen other problems, leading to wasted time and money on unnecessary parts. This isn’t just a replacement part; it’s a direct solution to get your vehicle’s brain functioning correctly again.
This is a reliable, used OEM PCM that we program specifically to your vehicle’s VIN before it leaves our facility. This critical step ensures all factory parameters for your engine and transmission are loaded correctly, incorporating the latest software updates from GM. You get a part that’s ready for installation right out of the box, saving you a costly trip to the dealership for programming.
Is Your GM Vehicle Showing These Symptoms?
A faulty PCM can cause a wide range of frustrating issues. I’ve diagnosed hundreds of these modules over the years, and the signs are often consistent. Look out for:
- ✔ Check Engine Light is on with communication codes (like U0100) or internal module failure codes (P0601, P0602, P0605).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling or rough idling, even after a tune-up.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ A noticeable drop in fuel economy.
- ✔ Failure to pass an emissions test due to module-related errors.
A Technician’s Notebook: The Intermittent Stall
A customer brought in a ’98 Chevy Express 2500 work van that would die intermittently at stoplights. They had already replaced the fuel pump and ignition coil with no success. After hooking up my scan tool, I noticed the live data feed from the PCM would freeze just before the engine cut out. There were no hard codes, just a ghost in the machine. We swapped in a VIN-programmed PCM like this one, and the problem was solved instantly. The original module’s internal processor was failing under heat soak—a classic failure mode for these units.
A Straightforward Guide to Installation
Installing your programmed PCM is a manageable job for a DIYer with basic tools. Following the proper sequence is key to avoiding electrical issues.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 15 minutes for the system capacitors to discharge.
- Locate the Old PCM: On most of these GM trucks and vans, the PCM is located in the engine compartment, often on the driver’s side fender well or near the battery. It’s a silver metal box with several large wiring harness connectors.
- Disconnect the Harnesses: Carefully unclip and remove the wiring harness connectors from the old PCM. Inspect the pins for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware as you will need it for the new unit.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and securely reconnect the wiring harnesses. You should hear a ‘click’ as they lock into place.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform Security Relearn (If Necessary): While we program the VIN, some GM vehicles of this era require a simple security relearn procedure to sync the new PCM with the anti-theft system. This typically involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your vehicle’s service information for specific steps if it doesn’t start immediately.
Verified Vehicle Compatibility
This module, identified by service number 9355699, is the correct replacement for a wide range of GM vehicles. It also directly interchanges with part numbers 16266645, 16250279, 16258815, and 09366810. Please match your part number or verify your vehicle is on the list below. Providing your VIN at checkout is essential for us to ensure perfect programming.
- ✔ 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline)
- ✔ 1998-1999 Chevrolet Suburban & GMC Yukon/Yukon XL (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, & Isuzu Hombre (4.3L V6)
- ✔ 1998 Chevrolet Blazer, GMC Jimmy, & Oldsmobile Bravada (4.3L V6)
- ✔ 1998 GMC Envoy (4.3L V6)
Do I need to do anything after I install it?
Do I need to do anything after I install it?
Because we program the module to your VIN, it should be a plug-and-play installation. However, on some models, a security relearn procedure (turning the key ‘on’ for 10-15 minutes) may be needed to sync with your vehicle’s anti-theft system. This does not require any special tools.
Is this a new part?
No, this is a high-quality, tested used OEM part sourced from a salvaged vehicle. We inspect and then program it with the latest GM software for your specific VIN, offering a reliable and cost-effective alternative to a new dealer part.
What information do you need from me?
After you complete your purchase, you must provide us with your vehicle’s 17-digit Vehicle Identification Number (VIN). We cannot ship the module until we have this information to program it correctly.
How do I find my current PCM’s part number?
The part number is printed on a sticker on the PCM itself. You will need to locate the module in your engine bay to read the sticker and confirm a match with 9355699 or one of the interchangeable numbers listed.