Restore Your GM Truck’s Performance and Reliability
Is your 1998-1999 GMC Yukon, Chevy Tahoe, or Suburban running rough, stalling unexpectedly, or showing a persistent Check Engine Light? A failing Powertrain Control Module (PCM) is often the culprit behind these frustrating and hard-to-diagnose issues. As the ‘brain’ of your vehicle, the PCM controls everything from fuel mixture and ignition timing to transmission shifting. When it fails, your truck’s performance and dependability suffer. This genuine OEM PCM, part number 9355699, is the straightforward, cost-effective solution to get your vehicle running properly again.
We take the guesswork and hassle out of the replacement process. Unlike a generic module from a parts store, this unit is meticulously programmed to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This means it arrives loaded with the latest GM software updates, ready for a simple installation without requiring an expensive trip to the dealership for programming. It’s a reliable part sourced from a salvaged vehicle, offering OEM quality at a fraction of the cost of a new unit.
Case Study: A Tricky Diagnosis
I remember a ’99 Suburban that came into my shop with a complaint that stumped two other mechanics: it would randomly refuse to start, but only when warm. There were no consistent trouble codes, just a vague U-series communication error that would pop up now and then. After checking all the usual suspects—battery, grounds, crank sensor—I focused on the PCM. On these GM trucks, I’ve seen the internal processors develop micro-fractures from years of heat cycles. When the engine got hot, the fracture would expand just enough to break a connection, killing the engine computer. Once it cooled, it would start right up. Swapping in a pre-programmed PCM like this one solved the problem instantly. The customer went from being ready to sell the truck to having his reliable family hauler back on the road.
Is Your GM Truck Showing These Signs?
A failing PCM can cause a wide range of symptoms. If you’re experiencing any of the following, your engine computer could be at fault:
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0605 (Internal Control Module Read Only Memory (ROM) Error).
- ✔ The engine cranks but refuses to start (no-start condition).
- ✔ Intermittent stalling or shutting off while driving.
- ✔ Rough or unstable idling.
- ✔ Noticeably poor fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass an emissions test.
A Straightforward Guide to Installation
Replacing the PCM on these GM vehicles is a job most DIYers can handle with basic tools. Our pre-programming makes it a true plug-and-play process. While specific locations vary slightly by model (e.g., engine compartment vs. by the battery), the general steps are consistent.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental contact.
- Locate the PCM: On most trucks and SUVs like the Yukon/Tahoe, it’s a silver metal box located in the left (driver’s side) of the engine compartment, near the fender. On Astro/Safari vans, it’s often near the battery.
- Disconnect the Connectors: Carefully unclip and remove the wiring harness connectors from the old PCM. There are typically multiple color-coded connectors; they only fit one way, so you can’t mix them up.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware as you will reuse it.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and secure it with the original hardware.
- Reconnect Everything: Firmly plug the wiring harness connectors into the new PCM until they click into place. Reconnect the negative battery terminal.
- Perform Security Relearn (If Necessary): In most cases, the vehicle will start and run perfectly. Some models may require a simple 10-30 minute security relearn procedure (Passlock/VATS). This can be done without any special tools by cycling the ignition key. Instructions are widely available online or in your service manual.
Verified Compatibility for Your Vehicle
This PCM is a direct replacement for service number 9355699 and is interchangeable with part numbers 09355699, 16266645, 16250279, 16258815, 09366810, and 9366810. It is guaranteed to fit a wide range of 1998-1999 GM and Isuzu models, including:
- Cadillac Escalade (1999)
- Chevrolet/GMC C/K 1500, 2500, 3500 Pickups (1998-1999, Gasoline)
- Chevrolet/GMC Suburban 1500, 2500 (1998-1999, Gasoline)
- Chevrolet Tahoe / GMC Yukon (1998-1999, Gasoline)
- Chevrolet Express / GMC Savana 1500, 2500, 3500 Vans (1998-1999, Gasoline)
- Chevrolet Astro / GMC Safari (1998)
- Chevrolet S10 / GMC Sonoma (1998, 4.3L)
- Chevrolet Blazer / GMC Jimmy (1998, 4.3L)
- Oldsmobile Bravada (1998)
- GMC Envoy (1998)
- Isuzu Hombre (1998, 4.3L)
Note: After purchasing, please provide your VIN to ensure we program the module correctly for your vehicle’s specific configuration.
Do I need to do any programming myself?
Do I need to do any programming myself?
No. We handle all the programming before shipping. We flash the module with the latest GM software updates using your vehicle’s VIN. It arrives ready to install.
Is this a new part?
This is a high-quality, used OEM (Original Equipment Manufacturer) computer that has been tested and sourced from a salvaged vehicle. This ensures perfect fitment and function compared to some aftermarket alternatives.
What is the security relearn procedure?
For some GM vehicles, the anti-theft system (VATS/Passlock) needs to be synchronized with the new PCM. This is a simple procedure that involves turning the key to the ‘ON’ position for 10 minutes, then ‘OFF’, and repeating two more times. It requires no special tools.
How do I provide my VIN?
After you complete your purchase, you will receive instructions on how to send us your 17-digit VIN. We cannot program and ship your module without it, so please provide it promptly to avoid delays.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM also controls transmission functions, including shift points and line pressure. If your shifting issues are caused by a faulty computer, this module will resolve them. However, it will not fix mechanical issues within the transmission itself.