Restore Your Truck’s Performance and Reliability
If your trusty 1998-1999 Chevrolet 3500 Pickup is suddenly giving you headaches—like stalling at intersections, hesitating on acceleration, or throwing a stubborn Check Engine Light—the problem often points to a failing Powertrain Control Module (PCM). As the central computer for your engine and transmission, a faulty PCM can create a cascade of frustrating issues. I’ve spent two decades under the hoods of these exact trucks, and I can tell you that a correctly programmed PCM is the key to bringing that dependable performance back.
This isn’t just any replacement part. This is a reliable, tested PCM sourced from a salvaged vehicle, which we then professionally program with the latest GM factory software updates using your vehicle’s specific VIN. This critical step ensures all systems communicate correctly, from fuel mixture to shift points, giving you a solution that works right out of the box without an expensive trip to the dealership for programming.
Case Study: A Tricky Diagnosis
A customer brought his ’99 GMC Suburban 2500 into my shop, a vehicle that shares this exact PCM. The complaint was intermittent stalling and a Check Engine Light with code P0601 (Internal Control Module Memory Check Sum Error). He’d already replaced a few sensors, hoping for an easy fix. After confirming power and grounds to the module were solid, we knew the PCM itself was the culprit. We installed a VIN-programmed module just like this one, performed the quick security relearn, and the truck ran perfectly. It’s a common failure on these GMT400 platforms, and this is the definitive, cost-effective fix.
Common Signs of a Failing PCM
- ✔ Your vehicle will not start or stalls intermittently.
- ✔ The Check Engine Light is on with codes like P0601, P0605, or other communication errors.
- ✔ You experience a noticeable drop in fuel economy.
- ✔ The transmission shifts harshly, erratically, or won’t shift out of a certain gear.
- ✔ You fail an emissions test due to module-related faults.
- ✔ The engine misfires or runs rough despite good spark plugs and coils.
A Straightforward Guide to Installation
Installing your programmed 1998-1999 Chevrolet 3500 PCM is a job most DIYers can handle in under an hour. Since we’ve done the programming, your job is just the physical swap.
- Safety First: Always disconnect the negative terminal from your truck’s battery before working on any electronic components.
- Locate the PCM: On most of these trucks, you’ll find the PCM in the engine compartment on the driver’s side (LH side), often near the fender or firewall.
- Disconnect the Connectors: Carefully unlatch and remove the wiring harness connectors from the old PCM. The levers can be stiff, so apply steady pressure. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. It’s typically held in by a few small bolts.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely reconnect the wiring harnesses. Ensure they click into place.
- Reconnect the Battery: Re-attach the negative battery terminal.
- Perform Security Relearn (Required): Do not skip this step! The vehicle will not start until this is done. Turn the key to the “ON” position (without starting the engine) for 10-11 minutes. The “Security” light on the dash should turn off. Turn the key completely off for 10 seconds. The truck should now start and run normally.
Will This Fit My Vehicle?
This PCM is a direct, programmed replacement for a wide range of GM trucks and vans from 1998-1999. It is compatible with multiple service numbers, including 09355699, 16266645, 16250279, 16258815, and 9366810. Please verify your vehicle is on the list below and that your original module carries one of these compatible part numbers.
This part is a confirmed fit for the following vehicles with service ID 9355699:
- ✔ 1998-1999 Chevrolet & GMC 1500, 2500, & 3500 Pickups (Gasoline)
- ✔ 1998-1999 Chevrolet & GMC 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
- ✔ 1998 GMC Envoy
- ✔ 1998 Isuzu Hombre (4.3L)
- ✔ 1998 Chevrolet S10 & GMC Sonoma (4.3L)
- ✔ 1998 Chevrolet Blazer & GMC Jimmy (4.3L)
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential. We use it to load the exact, correct GM software for your truck’s specific engine, transmission, and options. This ensures perfect compatibility and performance, eliminating the need for dealer programming.
Is this part difficult to install?
Not at all for someone with basic tools. The physical swap is simple, and we provide a step-by-step guide above. The most important part is the security relearn procedure, which just involves a few key cycles and about 10 minutes of waiting.
What if my original part number is 09355699?
No problem. This PCM, part number 9366810, is a fully compatible and interchangeable replacement for service number 09355699 and the other part numbers listed in our description. Once programmed to your VIN, it will function identically.
Is this a new part?
No, this is a high-quality, tested electronic control module sourced from a salvaged vehicle. This allows us to provide a reliable, cost-effective solution that has been proven to work in real-world conditions.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the PCM (like with codes P0601 or P0605), then yes, this part is the correct solution. However, you should always diagnose the codes properly to ensure the fault isn’t with a sensor or wiring before replacing the module.