Restore Your Van’s Performance and Reliability
Is your 1998-1999 GMC Savana 2500 Van running rough, stalling unexpectedly, or showing a persistent Check Engine Light? You’re not just dealing with an annoyance; you’re facing a failure of the vehicle’s central computer, the Powertrain Control Module (PCM). As a technician with over two decades of experience, I’ve seen countless work vans and trucks sidelined by faulty PCMs. The symptoms can be frustratingly intermittent, leading to wasted time and money on incorrect diagnoses. This replacement PCM is the reliable, cost-effective solution to get your vehicle back in service.
This isn’t just a used part pulled from a shelf. We take a quality, OEM-salvaged PCM and flash it with the latest official GM software updates specifically for your vehicle. By providing your Vehicle Identification Number (VIN) at checkout, you receive a module that is truly plug-and-play. It arrives ready to be installed, eliminating the need for an expensive trip to the dealership for programming. This service ensures that all engine and transmission parameters are set correctly for your specific 1998-1999 Savana 2500 PCM, restoring proper fuel economy, shift points, and engine performance.
Case Study: A Tricky Diagnosis
I remember a ’99 Suburban that came into my shop with a problem that was driving the owner crazy. It would start and run perfectly for days, then suddenly refuse to start. There were no consistent trouble codes, just an occasional loss of communication with the scan tool. After checking all the usual suspects—battery, grounds, ignition switch—we focused on the PCM. On these older GM trucks, heat and vibration are the enemy of the circuit board. We swapped in a pre-programmed PCM, and the problem vanished instantly. The internal circuitry of the original module had developed a micro-fracture that only caused an issue when it expanded or contracted just right. This is a classic failure mode that this replacement part directly solves.
Is Your GM Vehicle Showing These Symptoms?
A failing PCM can cause a wide range of issues. If you’re experiencing any of the following, a faulty module is a likely culprit:
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or other communication faults.
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling or rough idling.
- ✔ A noticeable decrease in fuel efficiency.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ The cooling fans run constantly or not at all.
- ✔ No communication with your OBD-II scan tool.
A Straightforward Guide to Swapping Your PCM
Installing your replacement 1998-1999 Savana 2500 PCM is a job most DIYers can handle in under an hour with basic tools. Follow these steps for a smooth installation:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts.
- Locate the PCM: On most Savana/Express vans, the PCM is located in the engine compartment on the driver’s side, near the airbox. On some trucks and SUVs, it’s on the driver’s side inner fender.
- 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 pulling on the wires themselves.
- Remove the Old Module: Unbolt the 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 bolts.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new PCM until they click into place. Reconnect the negative battery terminal.
- Security Relearn (If Necessary): In many cases, the vehicle will start and run immediately. However, some GM vehicles of this era may require a simple security relearn procedure (often called the Passlock or VATS relearn). This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. Consult your vehicle’s service information for the exact procedure.
Verified Vehicle Compatibility
This module, identified by part number 9355699, is a direct replacement for a wide range of GM vehicles. Please match your original part number or verify fitment with the list below. This part is compatible with service numbers 09355699, 16266645, 16250279, 16258815, 09366810, and 9366810.
CHEVROLET 1500 PICKUP 98 Electronic Control Module; gasoline (LH front engine compartment), ID 9355699
CHEVROLET 2500 PICKUP 98-99 Electronic Control Module; gasoline (LH front engine compartment), ID 9355699
CHEVROLET 3500 PICKUP 98-99 Electronic Control Module; gasoline (LH front engine compartment), ID 9355699
EXPRESS 1500 VAN 98-99 Electronic Control Module; ID 9355699
EXPRESS 2500 VAN 98-99 Electronic Control Module; gasoline, ID 9355699
EXPRESS 3500 VAN 98-99 Electronic Control Module; gasoline, ID 9355699
SAVANA 1500 VAN 98-99 Electronic Control Module; ID 9355699
SAVANA 2500 VAN 98-99 Electronic Control Module; gasoline, ID 9355699
SAVANA 3500 VAN 98-99 Electronic Control Module; gasoline, ID 9355699
SUBURBAN 1500 98-99 Electronic Control Module; gasoline (LH front engine compartment), ID 9355699
SUBURBAN 2500 98-99 Electronic Control Module; gasoline (LH front engine compartment), ID 9355699
TAHOE 98-99 Electronic Control Module; gasoline (LH front engine compartment), ID 9355699
GMC 1500 PICKUP 99 Electronic Control Module; 5.0L or 5.7L, (LH engine compartment), ID 9355699
GMC 1500 PICKUP 98 Electronic Control Module; gasoline (LH front engine compartment), ID 9355699
GMC 2500 PICKUP 98-99 Electronic Control Module; gasoline (LH front engine compartment), ID 9355699
GMC 3500 PICKUP 98-99 Electronic Control Module; gasoline (LH front engine compartment), ID 9355699
YUKON 98-99 Electronic Control Module; (LH engine compartment), ID 9355699
ASTRO 98 Electronic Control Module; (LH front by battery), ID 9355699
BLAZER S10/JIMMY S15 98 Electronic Control Module; (RH front engine compartment), w/o build date opt ZN4; ID 9355699
BRAVADA 98 Electronic Control Module; (6-262, 4.3L), w/o build date opt ZN4; ID 9355699
ENVOY 98 Electronic Control Module; (RH front engine compartment), w/o build date opt ZN4; ID 9355699
ESCALADE 99 Electronic Control Module; (LH front engine compartment), ID 9355699
ISUZU HOMBRE 98 Electronic Control Module; 4.3L (6 cylinder), w/o extended build date opt ZN4; ID 9355699
S10/S15/SONOMA 98 Electronic Control Module; 6-262 (4.3L), w/o build date opt ZN4; ID 9355699
SAFARI (GMC) 98 Electronic Control Module; (LH front by battery), ID 9355699
Frequently Asked Questions
Do I really need to provide my VIN?
Yes, absolutely. Your VIN is required to load the correct, vehicle-specific GM software onto the module. This ensures compatibility with your engine, transmission, and factory options, making the installation process as simple as possible.
Is this a new part?
This is a high-quality, tested, and fully functional used OEM (Original Equipment Manufacturer) part that has been sourced from a salvaged vehicle. It is then professionally programmed to your vehicle’s specifications.
Will I need to do a CASE relearn?
A Crankshaft Variation Relearn (CASE) may be required to prevent a P1336 trouble code. This procedure calibrates the PCM to the crankshaft position sensor. Many professional-grade scan tools can perform this function, or a local repair shop can do it for a small fee.
What if my original part number is slightly different?
This module replaces several part numbers, including 16266645, 16250279, and others listed above. As long as your vehicle is on the compatibility list and your original module is one of the listed service numbers, this part will work perfectly once programmed with your VIN.
Is this difficult to install myself?
For most people with basic hand tools, this is a straightforward DIY repair. The module is typically easy to access in the engine bay. The main benefit of our service is that the complex programming is already done for you.