Is Your Chevy Express Van Running Rough? Get a Reliable, Programmed Solution.
As a technician with over two decades of experience, I’ve seen countless GM trucks and vans from this era suffer from frustrating, hard-to-diagnose issues. A flickering check engine light, poor fuel economy, or a van that just won’t start can bring your work or your trip to a grinding halt. Often, the culprit is a failing Powertrain Control Module (PCM), the central computer of your vehicle. Replacing it used to mean an expensive part from the dealer followed by a mandatory trip for costly programming. Not anymore.
This is a dependable, used OEM Engine Control Module (ECM) that’s been meticulously tested and is ready for installation. The best part? We handle the programming for you. Simply provide your vehicle’s VIN at checkout, and we will flash this module with the latest, most stable GM software updates specific to your 1998-1999 Express 1500 PCM. This ensures perfect compatibility and often resolves underlying software bugs that the original module had from the factory, restoring your van’s performance and reliability.
Case Study: A Tricky Diagnosis
I remember a 1999 Suburban that came into my shop with a bizarre set of symptoms: intermittent stalling at idle, harsh 1-2 shifts, and a fuel gauge that read empty even with a full tank. The owner had already replaced the fuel pump and a few sensors with no luck. After connecting my scan tool, I saw no communication with the PCM (a classic U-code symptom). We swapped in a known-good, programmed PCM like this one, and every single issue vanished instantly. The original module’s internal processor had failed, a common issue I’ve seen on at least a hundred of these GM units. This simple swap saved the customer hundreds in further diagnostic fees and unnecessary parts.
Is Your Vehicle Showing These Symptoms?
- ✔ Check Engine Light is on with communication error codes (like P0601, P0605) or various sensor codes.
- ✔ Your engine cranks but refuses to start.
- ✔ The transmission is shifting erratically, harshly, or at the wrong times.
- ✔ You’re experiencing a noticeable drop in fuel economy.
- ✔ The vehicle fails an emissions test.
- ✔ Intermittent stalling or rough idling for no apparent reason.
A Straightforward Guide to Your 1998-1999 Express 1500 PCM Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- ✔ Locate the PCM: On most Express/Savana vans, the PCM is located in the engine compartment, on the driver’s side, often near the battery or air filter housing.
- ✔ Disconnect Connectors: Carefully unclip the wiring harness connectors from the old module. These connectors have locking tabs; be gentle to avoid breaking them.
- ✔ Remove the Old Module: Unbolt the old PCM from its mounting bracket. It’s typically held in by a few 10mm bolts.
- ✔ Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely re-fasten the bolts.
- ✔ Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click into place. Reconnect your negative battery terminal.
- ✔ Perform Security Relearn: You will likely need to perform a Crankshaft Variation Relearn (CASE Relearn) procedure. This can be done with a capable bi-directional scan tool or by following a specific key-cycle procedure (often called the “Passlock Relearn”). This syncs the new PCM with your vehicle’s anti-theft system.
Verified Vehicle Compatibility
This module is a direct replacement for service numbers 09355699, 16266645, 9355699, 16250279, 16258815, and 9366810. It is guaranteed to fit a wide range of GM trucks and vans that require the module with ID 9355699. Please verify your part number or contact us with your VIN to ensure a perfect match. Key compatible models include:
BLAZER S10/JIMMY S15 98 (RH front engine compartment)
BRAVADA 98 (6-262, 4.3L)
CHEVROLET/GMC 1500/2500/3500 PICKUP 98-99 (Gasoline)
ESCALADE 99 (LH front engine compartment)
EXPRESS 1500/2500/3500 VAN 98-99 (Gasoline)
ISUZU HOMBRE 98 (4.3L)
S10/S15/SONOMA 98 (4.3L)
SAFARI (GMC) 98 (LH front by battery)
SAVANA 1500/2500/3500 VAN 98-99 (Gasoline)
SUBURBAN 1500/2500 98-99 (Gasoline)
TAHOE/YUKON 98-99 (Gasoline)
Frequently Asked Questions
What does “programmed to my VIN” mean?
It means we load your vehicle’s specific Vehicle Identification Number (VIN) and all related factory software, including the latest GM updates, onto the module before shipping. This ensures it communicates perfectly with your engine, transmission, and other systems, just like the original part.
Is this part difficult to install for a DIYer?
The physical installation is straightforward, typically requiring only basic hand tools to swap the module. The only additional step is the Security Relearn (CASE Relearn), which is critical for the vehicle to start. Many resources online show how to do this, or any local shop can perform it quickly.
This is a used part. How can I be sure it works?
Every module we sell is sourced from a salvaged vehicle and then undergoes rigorous bench testing to ensure all circuits and processors are fully functional. We then flash it and verify communication before it’s approved for sale. It’s a reliable and economical repair.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the PCM (common codes include P0601-P0606), then yes, this will resolve the issue. However, if the light is on due to a faulty sensor or other component, you will still need to address that separate problem. This module fixes the ‘brain,’ not the ‘sensors.’