Get Your GM Truck or Van Running Smoothly Again
Is your 1998 Chevrolet Astro, or another GM vehicle from that era, giving you headaches? If you’re dealing with frustrating issues like a no-start condition, intermittent stalling, poor fuel economy, or a persistent Check Engine Light, 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 falters, everything else follows. In my 20+ years of diagnostics, I’ve seen countless vehicles sidelined by a faulty computer, but the fix is often more straightforward and affordable than you think.
This is a reliable, OEM Powertrain Control Module (part number 09355699) sourced from a salvaged vehicle. The real value here is that we take the guesswork and extra cost out of the repair. Before we ship it, our technicians will program the module specifically for your vehicle using your VIN. This means it arrives at your door loaded with the latest GM software updates, ready for installation. You get a part that restores original performance and reliability without the hefty price tag and programming fees of a dealership.
A Technician’s Notebook: The Phantom Misfire
A customer brought in a ’99 Suburban with a random misfire that no one could pin down. They had replaced plugs, wires, cap, rotor, and even the fuel injectors. The misfire would come and go, and the scanner showed conflicting data. After checking all the wiring and grounds, we hooked up a lab scope to the injector command signals at the PCM. We found that the signal for cylinder 3 would occasionally drop out completely. The injector was fine, the wiring was fine—the driver inside the PCM itself was failing intermittently. We installed a pre-programmed module just like this one, and the truck ran perfectly. It’s a classic example of how a failing 1998 Astro PCM or its equivalent can create phantom problems that seem impossible to solve.
Is Your GM Vehicle Showing These Symptoms?
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, a replacement module is the most likely solution. Watch for Diagnostic Trouble Codes (DTCs) like P0601, P0605, or U-series communication codes.
- ✔ Vehicle refuses to start or starts and immediately stalls.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ A significant, unexplained drop in fuel mileage.
- ✔ Check Engine Light is on with internal module error codes (e.g., P0601).
- ✔ Engine misfires, stumbles, or hesitates during acceleration.
- ✔ Loss of communication with the diagnostic scan tool.
A Straightforward Guide to Installation
Installing your programmed 1998 Astro PCM is a job most DIYers can handle in their own driveway. Following these steps ensures a smooth process.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the PCM: On most of these trucks and vans, the PCM is located in the engine compartment, often on the driver’s side fender well or near the battery.
- Disconnect the Connectors: Carefully unclip the wiring harness connectors from the old module. These connectors have locking tabs; be gentle to avoid breaking them.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. It’s typically held in place by a few small bolts.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten the bolts.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click into place. Reconnect the negative battery terminal.
- Final Check: Turn the key to the ‘On’ position (without starting) for 10-15 seconds, then turn it off. Repeat this once more. You can now start the vehicle. The engine should start and run smoothly.
Will This Fit My Truck or Van?
We guarantee this module is a direct fit for a wide range of GM vehicles when you match the part number 09355699. This unit also replaces part numbers 16266645, 16250279, 16258815, 09366810, and 9366810. Please verify your vehicle is on the list below and that your original module carries one of these numbers.
ASTRO 98, BLAZER/JIMMY S-Series 98, BRAVADA 98, CADILLAC ESCALADE 99, CHEVROLET/GMC PICKUPS (1500/2500/3500) 98-99, EXPRESS/SAVANA VANS (1500/2500/3500) 98-99, ISUZU HOMBRE 98, S10/SONOMA 98, SUBURBAN 98-99, TAHOE/YUKON 98-99, and more. It is critical to match the ID number 09355699.