Get Your GM Truck Running Right Again
Is your 1998 Chevy Blazer, GMC Jimmy, or another GM truck from that era giving you headaches? If you’re dealing with a persistent check engine light, a no-start condition that has you stumped, rough idling, or failing emissions tests, the problem often points directly to a failing Powertrain Control Module (PCM). As the brain of your vehicle’s engine and transmission, when the PCM starts to fail, it can create a host of confusing and frustrating issues. This isn’t just an inconvenience; it’s a critical failure that sidelines your vehicle.
The Direct Solution: A Reliable, Programmed PCM
Forget the guesswork and the high cost of a dealership visit. This is a dependable, used OEM PCM identified by service number 09355699. Before this module ever leaves our shop, we flash it with the latest official GM software updates, programming it specifically to your vehicle’s VIN. This isn’t a generic, one-size-fits-all part; it’s prepared to be a direct, plug-and-play replacement for your original faulty unit.
- ✔ VIN Programmed: We load your vehicle’s specific information, ensuring it communicates perfectly with your truck’s systems.
- ✔ Latest GM Software: Flashed with the newest calibrations to correct factory bugs and improve performance and efficiency.
- ✔ Cost-Effective Repair: Get a reliable, tested part without the steep price tag of a new-from-dealer module.
- ✔ Plug-and-Play Ready: Arrives ready for installation, minimizing vehicle downtime.
From the Shop Floor: A Real-World Scenario
A customer’s 1998 GMC Jimmy S15 came in last week with these exact symptoms. It would crank but not start, and the fuel pump wasn’t priming. The owner had already replaced the pump and the ignition coil, with no luck. A quick scan with our diagnostic tool showed a ‘No Communication with PCM’ error. This is a classic sign of internal failure on these modules. We installed one of these VIN-programmed units, performed the security relearn, and the truck fired up on the first try. It’s a repair I’ve done hundreds of times on these GM platforms.
Diagnosing a Faulty 1998 Blazer S10 PCM
While a proper scan tool is the best diagnostic method, a failing PCM often reveals itself through a pattern of symptoms. If your truck is experiencing several of the following, the PCM is a highly probable cause:
- ✔ The engine cranks but refuses to start.
- ✔ Check Engine Light is on with communication error codes (like U-codes) or multiple random sensor codes.
- ✔ Poor or erratic automatic transmission shifting.
- ✔ Noticeable drop in fuel economy.
- ✔ The engine stalls intermittently, especially after warming up.
Simple Installation: Get Back on the Road Fast
You don’t need to be a master technician to replace this module. With basic hand tools, you can have your truck running again in under an hour. For the 1998 Blazer S10/Jimmy S15, the PCM is typically located in the engine bay on the right-hand (passenger) side.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: Find the module, usually mounted to the inner fender or firewall.
- Disconnect Connectors: Carefully unplug all wiring harness connectors from the old PCM. These often have locking levers or tabs that need to be released.
- Remove Old Module: Unbolt the old PCM from its mounting bracket.
- Install New Module: Bolt the new, programmed PCM into place.
- Reconnect Everything: Securely plug in all wiring harness connectors and reconnect the negative battery terminal.
- Perform Security Relearn: This is a critical final step. See our expert tip below.
Expert Pro Tip: Don’t Skip the Security Relearn!
Your 1998 GM vehicle is equipped with a Passlock II anti-theft system. After installing the new PCM, the truck will not start until you perform the security relearn procedure. It’s simple and requires no tools: Turn the key to the ‘ON’ position (don’t start it), and wait for the ‘Security’ light on the dash to turn off. This takes about 10-12 minutes. Once it’s off, turn the key off for 10 seconds. Repeat this cycle two more times for a total of three cycles. After the third cycle, the vehicle will start and run normally. Skipping this step will make you think the part is defective when it’s not.
Guaranteed Fitment for Part Number 09355699
This module is a direct replacement for units with the service number 09355699 printed on the white sticker. To ensure compatibility, please check the part number on your existing computer. This unit also replaces the following interchangeable part numbers:
16266645, 9355699, 16250279, 16258815, 09366810, 9366810
While programmed for your specific VIN, this hardware is compatible with a wide range of 1998-1999 GM trucks and vans, including the Chevrolet/GMC 1500/2500/3500 Pickups, Suburban, Tahoe, Yukon, Astro, Safari, Express, and Savana vans, as well as the Cadillac Escalade, Oldsmobile Bravada, GMC Envoy, and Isuzu Hombre. For S-series platforms (Blazer, Jimmy, S10, Sonoma, etc.), this fits vehicles without the extended build date option ZN4.