Restore Your Truck’s Brain and Bring It Back to Life
Is your trusty GMC or Chevy truck suffering from perplexing issues like a persistent check engine light, erratic shifting, or a frustrating no-start condition? Before you start throwing expensive parts at it, the problem might be its central computer. The Powertrain Control Module (PCM) is the brain of your vehicle, managing everything from fuel delivery and spark timing to transmission shifts. When it fails, it can cause a host of problems that can be difficult to diagnose. This is a reliable, tested, and pre-programmed replacement PCM that gets your vehicle running right again without the excessive cost and hassle of a dealership visit.
From the Diagnostic Bay
I remember a 1999 Chevy Suburban that came into the shop a few years back. The owner was at his wit’s end. It would randomly stall at red lights and sometimes refuse to start for an hour. He’d already replaced the fuel pump and ignition coil. After hooking up my scan tool, I saw intermittent communication loss with the PCM and a stored P0601 code (Internal Control Module Memory Check Sum Error). These old PCMs are tough, but decades of heat cycles and vibration eventually take their toll on the internal circuit boards. We swapped in a pre-programmed module just like this one, and the truck has been running reliably for him ever since. It’s often the last thing people suspect, but the first thing that solves the problem.
Is Your Truck or Van Showing These Signs?
A failing PCM can manifest in various ways. If you’re experiencing any of the following, this module is a likely solution:
- ✔ Persistent Check Engine Light (CEL)
- ✔ Engine stalling or cutting out intermittently
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Complete no-start condition where the engine cranks but won’t fire
- ✔ Poor fuel economy and decreased engine performance
- ✔ Communication error codes, such as P0601, P0605, or other U-codes
- ✔ Failure to pass an emissions/smog test
The Smart Solution: Pre-Programmed for Your VIN
The biggest hurdle in replacing a modern vehicle computer isn’t the physical installation—it’s the software. This isn’t just a part; it’s a complete solution. We take a quality, tested, used OEM module and flash it with the latest official GM software calibrated specifically for your vehicle’s VIN. This ensures all systems, from the engine to the anti-theft system, communicate correctly from the moment you install it. You get a part that works like new without paying the dealership for the module AND several hundred dollars more for programming.
A Straightforward Guide to Installation
Replacing the PCM on these GM trucks and vans is a job most DIYers can handle in under 30 minutes with basic hand tools. Here’s a general guide:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: On most trucks and SUVs like the GMC 1500 or Tahoe, the PCM is located in the engine bay, typically on the driver’s side inner fender well in a black plastic bracket. On Express/Savana vans, it’s often at the rear of the engine compartment.
- Disconnect the Harnesses: Carefully unclip and disconnect the multiple wiring harness connectors. These connectors have locking tabs; be gentle to avoid breaking them.
- Remove the Old Module: Unbolt the PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Seat your pre-programmed PCM into the bracket, secure the bolts, and reconnect all the wiring harnesses. Ensure they click firmly into place.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform CASE Relearn (If Needed): In many cases, you may need a scan tool to perform a Crankshaft Variation Relearn (also known as CASE relearn) to prevent a P1336 trouble code. Many local shops can perform this service for a minimal fee if you don’t have the tool.
Verified Vehicle Compatibility
This module, identified by service ID 9355699, is a direct replacement for a wide range of GM vehicles. It is compatible with part numbers 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. Please verify your part number or consult the list below. This module fits the following vehicles:
- 1998-1999 Chevrolet & GMC 1500/2500/3500 Pickups (Gasoline)
- 1998-1999 Chevrolet Suburban 1500/2500 (Gasoline)
- 1998-1999 Chevrolet Tahoe & GMC Yukon (Gasoline)
- 1999 Cadillac Escalade
- 1998-1999 Chevrolet Express & GMC Savana 1500/2500/3500 Vans (Gasoline)
- 1998 Chevrolet Astro & GMC Safari
- 1998 Oldsmobile Bravada (w/o build date opt ZN4)
- 1998 GMC Envoy (w/o build date opt ZN4)
- 1998 Chevrolet S10 / GMC Sonoma (4.3L, w/o build date opt ZN4)
- 1998 Chevrolet Blazer / GMC Jimmy (w/o build date opt ZN4)
- 1998 Isuzu Hombre (4.3L, w/o extended build date opt ZN4)
Frequently Asked Questions
Why do I need to provide my VIN?
Your vehicle’s 17-digit Vehicle Identification Number (VIN) allows us to load the exact, correct GM software for your truck’s specific engine, transmission, and options. This ensures seamless integration and proper function, eliminating the need for a trip to the dealer for programming.
Is this part difficult to install?
No, the physical installation is very straightforward for most DIY mechanics. It typically involves disconnecting the battery, unplugging a few connectors, and unbolting the old module. The most important part, the software programming, is already done for you.
What is a CASE Relearn and will I need to do it?
A Crankshaft Variation (CASE) Relearn synchronizes the PCM with the crankshaft position sensor. After installing a new PCM, it’s often necessary to prevent a P1336 trouble code. While the truck will usually run without it, we recommend having it done for optimal performance. Most local repair shops can perform this procedure quickly with a capable scan tool.
Is a used PCM reliable?
Absolutely. We source these modules from salvaged vehicles and thoroughly test them to ensure they are fully functional. By flashing them with the latest software, we are also able to correct potential factory bugs. It’s a cost-effective and dependable way to get your truck back on the road.
Will this fix my ‘No Communication’ issue?
In many cases, yes. When a scan tool cannot communicate with the PCM, it’s a very strong indicator that the module itself has failed internally. Replacing it with this tested and programmed unit is the standard professional repair for that condition.