Restore Your Van’s Performance and Reliability
Is your trusty 1998 Chevrolet Astro or GMC Safari suddenly giving you headaches? Unexplained stalling, a persistent check engine light, or erratic engine behavior can often be traced back to a failing Powertrain Control Module (PCM). As the central computer of your vehicle, the PCM is responsible for managing everything from fuel delivery and ignition timing to transmission shifting. When it starts to fail, it can cause a host of frustrating and difficult-to-diagnose problems.
This is a dependable, tested used PCM, part number 9355699, sourced from a salvaged vehicle. We take the guesswork and high cost out of the repair by programming the module specifically for your vehicle before it ships. Just provide us with your Vehicle Identification Number (VIN) after purchase, and we’ll flash it with the latest GM software updates. This ensures it’s a true plug-and-play solution, getting you back on the road without a mandatory, expensive trip to the dealership for programming.
From the Diagnostic Bay: The Case of the Warm-Stall Astro
I remember a customer bringing in his ’98 Astro van with a baffling issue. It would run perfectly for about 20 minutes, but as soon as it reached full operating temperature, it would sputter and stall at stoplights. No specific codes, just a general loss of communication now and then. We checked fuel pressure, sensors, and wiring, but everything looked fine. From experience, I know that internal circuit board failures in these older PCMs often show up with heat soak. We temporarily swapped in a known-good PCM, and the problem vanished. The heat was causing a hairline crack in a solder joint on the original board to expand and break the connection. This is a classic failure mode, and a replacement PCM like this one is the direct and correct fix.
Is Your Vehicle Showing These Signs of PCM Failure?
A faulty PCM can manifest in many ways. If you’re experiencing any of the following, a failing engine computer could be the culprit. Look out for Diagnostic Trouble Codes (DTCs) like P0601, P0602, or P0605, which point directly to an internal module fault.
- ✔ Vehicle refuses to start or has a hard time starting.
- ✔ Check Engine Light is on or flashes intermittently.
- ✔ Poor or declining fuel economy.
- ✔ Engine stalling, stumbling, or idling roughly.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Loss of power and sluggish acceleration.
- ✔ Communication errors with a scan tool.
A Straightforward Guide to Your 1998 Astro PCM Installation
Replacing the PCM on these GM vans and trucks is a job most DIYers can handle with basic tools. Our pre-programming service makes it even simpler. Follow these general steps to get your vehicle running smoothly again.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent any accidental reconnection.
- Locate the PCM: On the 1998 Astro and Safari, the PCM is typically located in the engine compartment on the driver’s side, near the battery. On other compatible vehicles, it may be on the driver’s or passenger’s side fender well.
- Disconnect the Harnesses: Carefully unclip and disconnect 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 mounting hardware that secures the PCM to its bracket or the vehicle body. Remove the old module.
- Install the New Module: Place your replacement PCM into the mounting bracket and secure it with the original hardware.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new PCM until they click into place. Reconnect the negative battery terminal.
- Final Steps: In some cases, a security relearn procedure may be necessary for the vehicle to start. This procedure (often called Passlock or Passkey relearn) can typically be done without special tools and instructions are widely available online.
Verified Vehicle Compatibility
This module is a direct replacement for service number 9355699 and is interchangeable with part numbers 16266645, 16250279, 16258815, and 9366810. Please verify your original part number matches before ordering. It is confirmed to fit the following vehicles with the specified options:
- ✔ 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline)
- ✔ 1998-1999 Chevrolet Tahoe & GMC Yukon (Gasoline)
- ✔ 1998-1999 Chevrolet & GMC Suburban 1500, 2500 (Gasoline)
- ✔ 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans (Gasoline)
- ✔ 1999 Cadillac Escalade
- ✔ 1998 Chevrolet Astro & GMC Safari
- ✔ 1998 Chevrolet S10 & GMC Sonoma (4.3L V6)
- ✔ 1998 Chevrolet Blazer & GMC Jimmy (4.3L V6)
- ✔ 1998 Oldsmobile Bravada
- ✔ 1998 GMC Envoy
- ✔ 1998 Isuzu Hombre (4.3L V6)
Frequently Asked Questions
Frequently Asked Questions
Why do you need my VIN?
Your VIN (Vehicle Identification Number) allows us to program the PCM with the exact software and calibrations for your vehicle’s specific engine, transmission, and options. This ensures perfect compatibility and function right out of the box.
Is this a new part?
No, this is a high-quality, tested used PCM that has been carefully removed from a salvaged vehicle. This provides a reliable and cost-effective solution compared to a new module from the dealer.
Will I need to do anything else after installation?
Because we pre-program the module, no further programming is typically required. However, some GM vehicles of this era may require a simple security relearn procedure to sync the module with the vehicle’s anti-theft system. This can usually be done in your driveway.
What does the PCM actually do?
The Powertrain Control Module is the main computer for your vehicle. It takes information from sensors all over the engine and transmission to control fuel injection, spark timing, and transmission shift points for optimal performance, fuel economy, and emissions.
How do I find my part number?
Your original PCM will have a sticker on it with the service number. For this part, you should see ‘SERV. NO. 09355699‘ or one of the other compatible numbers listed in the description. Matching this number is the best way to guarantee fitment.