Restore Your GMC Safari’s Reliability and Performance
If you’re dealing with frustrating issues like your 1998 GMC Safari not starting, stalling unexpectedly, or throwing a persistent check engine light, a failing Powertrain Control Module (PCM) is often the culprit. As the brain of your vehicle’s engine and transmission, when the PCM goes bad, it can cause a cascade of problems that are difficult to diagnose. This isn’t just an inconvenience; it’s a reliability issue that can leave you stranded. I’ve seen countless GM vans and trucks from this era in my shop with these exact symptoms, and a quality, correctly programmed PCM is the definitive solution.
A Technician’s Notebook: The Intermittent No-Start Nightmare
I remember a customer with a ’98 Astro van—the Safari’s twin—that had a ghost of a problem. It would start and run perfectly for weeks, then suddenly refuse to start. No crank, no fuel pump prime, nothing. He had replaced the battery, starter, and ignition switch. When it got to my bay, it started right up, of course. After digging into the schematics, I focused on the PCM’s power and ground circuits. Everything checked out. The breakthrough came when I lightly tapped on the PCM housing with a screwdriver handle while the engine was running—it immediately stalled and wouldn’t restart. The internal connections had failed. A replacement, programmed PCM like this one had him back on the road permanently, solving a problem that had plagued him for months. These failures are common due to age, heat cycles, and vibration.
This isn’t just a used computer pulled from a junkyard. This is a dependable, fully tested OEM engine computer that we professionally program specifically for your vehicle. Simply provide us with your VIN after purchase, and we’ll flash the module with the latest GM software updates. This ensures it communicates perfectly with your van’s systems, restoring the original performance and fuel efficiency you expect. It’s the most effective way to solve the problem without the excessive cost and hassle of a dealership visit for programming.
Is Your GM Vehicle Showing These Signs of PCM Failure?
- ✔ Engine cranks but will not start
- ✔ Unexplained check engine light, especially with codes like P0601 or P0605 (Internal Control Module Memory/ROM Error)
- ✔ Intermittent stalling or rough idling
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Loss of communication with the scan tool
- ✔ Poor fuel economy or engine performance
A Straightforward Guide to Installation
Replacing the PCM in your Safari is a job most DIYers can handle in under an hour with basic hand tools. Our pre-programming service makes the process much simpler.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On your 1998 GMC Safari or Chevrolet Astro, the PCM is located in the engine compartment on the driver’s side, typically near the battery.
- Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that need to be released. Once unplugged, unbolt the module from its mounting bracket and remove it.
- Install the New PCM: Mount your new, pre-programmed PCM and securely reconnect the electrical harnesses. Ensure they click into place.
- Reconnect Power: Reattach the negative battery terminal.
- Perform Security Relearn: You will need to perform a simple security relearn procedure so the vehicle recognizes the new PCM. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. Your vehicle’s service manual will have the exact steps.
Verified Vehicle Compatibility
This module, identified by part number 09355699, is a direct replacement for a wide range of GM trucks, vans, and SUVs. It is interchangeable with part numbers 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. Please verify your vehicle is on the list below and that your original module carries one of these numbers for guaranteed compatibility.
BLAZER S10/JIMMY S15 98 (RH front engine compartment), w/o build date opt ZN4
BRAVADA 98 (6-262, 4.3L), w/o build date opt ZN4
CHEVROLET 1500 PICKUP 98-99 (gasoline, LH engine compartment)
CHEVROLET 2500 PICKUP 98-99 (gasoline, LH engine compartment)
CHEVROLET 3500 PICKUP 98-99 (gasoline, LH engine compartment)
ENVOY 98 (RH front engine compartment), w/o build date opt ZN4
ESCALADE 99 (LH front engine compartment)
EXPRESS 1500 VAN 98-99
EXPRESS 2500 VAN 98-99 (gasoline)
EXPRESS 3500 VAN 98-99 (gasoline)
GMC 1500 PICKUP 98-99 (gasoline, LH engine compartment)
GMC 2500 PICKUP 98-99 (gasoline, LH engine compartment)
GMC 3500 PICKUP 98-99 (gasoline, LH engine compartment)
ISUZU HOMBRE 98 (4.3L), w/o extended build date opt ZN4
S10/S15/SONOMA 98 (6-262, 4.3L), w/o build date opt ZN4
SAFARI (GMC) 98 (LH front by battery)
SAVANA 1500 VAN 98-99
SAVANA 2500 VAN 98-99 (gasoline)
SAVANA 3500 VAN 98-99 (gasoline)
SUBURBAN 1500 98-99 (gasoline, LH front engine compartment)
SUBURBAN 2500 98-99 (gasoline, LH front engine compartment)
TAHOE 98-99 (gasoline, LH front engine compartment)
YUKON 98-99 (LH engine compartment)
Frequently Asked Questions
What is VIN programming and why do I need it?
VIN programming loads your vehicle’s unique identification number and specific operational software onto the PCM. This is critical for ensuring the engine, transmission, anti-theft system, and other electronics work together correctly. Our service handles this for you, so it’s ready for installation.
Is this part difficult to install myself?
For most DIYers with basic tools, this is a very manageable job. The main steps are disconnecting the battery, swapping the module, and performing a security relearn procedure. Our guide above outlines the process.
Will I need a mechanic or special tools after installation?
No special tools are required. The only post-installation step is the security relearn, which can be done without a scan tool. This saves you a trip to the dealer or mechanic for programming.
How can I be sure this fits my vehicle?
The best way is to match the part number from your original PCM to one of the numbers listed (09355699, 16266645, etc.). Also, confirm your vehicle’s make, model, and year are on our compatibility list.
Is this a new computer?
No, this is a thoroughly tested, genuine OEM computer sourced from a salvaged vehicle. We find these to be highly reliable. Each unit is professionally programmed and verified to be fully functional before shipping.