Is your 1998 or 1999 GMC Savana 2500 van running rough, stalling, or refusing to start? Are you battling a persistent Check Engine Light that points to an internal computer failure? These are classic signs of a failing Powertrain Control Module (PCM), the central computer that manages your vehicle’s engine and transmission performance. A faulty PCM can lead to a host of frustrating and unpredictable issues, making your reliable workhorse feel anything but. This replacement PCM is the definitive solution to restore your van’s performance and reliability.
This unit is a genuine, tested component sourced from a salvaged vehicle, offering a dependable and cost-effective alternative to expensive dealership parts. What sets our service apart is the crucial programming step we handle for you. Before this module ships, we flash it with the latest official GM software updates, specifically calibrated to your vehicle’s unique Vehicle Identification Number (VIN). This ensures seamless integration and optimal performance right out of the box. You get a plug-and-play part that eliminates the need for a costly trip to the dealership for programming.
From the Diagnostic Bay
We had a local contractor bring in his ’99 Express 2500, a sister van to the Savana. The complaint was intermittent stalling at stoplights and a hard, clunky shift from first to second gear. He’d already replaced the throttle position sensor and cleaned the MAF sensor with no luck. His scanner was showing a U-code for lost communication with the PCM. Instead of chasing more sensors, we hooked up our scope and saw the PCM’s 5-volt reference signal was dropping out randomly. We installed one of these VIN-programmed modules, and the van immediately ran like new. The smooth shifting returned, the stalling vanished, and he was back on the job the same afternoon without the high cost of a new module and dealer programming.
Diagnosing and Replacing Your 1998-1999 Savana PCM
A failing 1998-1999 Savana PCM can manifest in various ways, often mimicking other sensor or component failures. If you’ve checked your basics—battery, alternator, fuel pressure, and ignition components—and the problems persist, the PCM is a likely culprit. Common diagnostic trouble codes (DTCs) include P0601 (Internal Control Module Memory Check Sum Error), P0606 (PCM Processor Fault), or various communication errors (U-codes). Replacing the PCM is a straightforward process for a DIY mechanic. It’s typically located in the engine bay, secured by a few bolts and connected by several large electrical harnesses. With our pre-programmed unit, the process is as simple as disconnecting the battery, swapping the old module for the new one, and reconnecting the battery. No special tools or software are required.
Common Symptoms of a Failing PCM
- ✔ Check Engine Light: The light is on, and you may have codes related to internal module failure or sensor circuits.
- ✔ Engine Stalling or Misfiring: The engine may stall unexpectedly, run rough, or misfire as the PCM fails to properly control fuel and spark.
- ✔ No-Start Condition: The engine cranks but won’t start because the PCM isn’t activating the fuel pump or ignition coils.
- ✔ Poor Fuel Economy: Inefficient engine operation due to incorrect fuel and air mixture calculations by the failing module.
- ✔ Erratic Transmission Shifting: The PCM controls shift points in the automatic transmission, and a failure can cause harsh, delayed, or incorrect shifting.
- ✔ Failed Emissions Test: The vehicle will not pass an emissions test if the PCM is not functioning correctly.
This module is a direct replacement for part numbers 16266645, 09355699, 9355699, 16250279, 16258815, 09366810, and 9366810. It fits a wide range of GM trucks and vans from 1998-1999, including the Chevrolet Express, Suburban, Tahoe, and GMC Yukon. Please provide your VIN upon purchase to ensure we can program the module for a perfect match to your vehicle’s specifications.
Frequently Asked Questions
Why do you need my VIN?
Your vehicle’s VIN (Vehicle Identification Number) allows us to program the PCM with the exact software and calibrations specific to your engine, transmission, and factory options. This ensures the module works perfectly once installed, without any additional programming.
Is this a new part?
No, this is a high-quality, thoroughly tested used part that has been sourced from a salvaged vehicle. Each unit is inspected and verified to be fully functional before being programmed and shipped.
Will I need to do anything else after installing it?
No. Because we program the module to your VIN, it is a plug-and-play installation. In some cases, a security relearn procedure may be necessary, which is a simple process that can be done without any special tools. Instructions can be provided if needed.
Where is the PCM located on my 1999 Savana 2500?
On most 1998-1999 GMC Savana and Chevrolet Express vans, the PCM is located in the engine compartment, typically on the driver’s side near the battery or on the inner fender.
Will this PCM fix my transmission shifting problems?
It very well could. The PCM controls both engine and transmission functions. If your shifting issues are caused by faulty electronic commands from the computer, replacing the PCM will resolve them. However, it will not fix internal mechanical issues with the transmission.