Is Your GM Truck or SUV Running Rough? The PCM Might Be the Culprit.
As a technician with over two decades of experience under the hood, I’ve seen it all. When a late-90s GM truck or SUV like your 1998 Oldsmobile Bravada starts acting up—stalling at stoplights, shifting erratically, or refusing to start altogether—the root cause is often the very brain of the operation: the Powertrain Control Module (PCM). It’s a frustrating problem that can leave you stranded. This isn’t just a part; it’s the central command for your engine’s performance, fuel economy, and emissions. When it fails, your reliable workhorse becomes a driveway ornament.
We offer a dependable and straightforward solution. This is a genuine, road-tested OEM PCM with service number 09355699. Unlike questionable aftermarket units that can cause more headaches than they solve, this is the original equipment designed by GM for your vehicle. We take this reliable hardware and flash it with the latest official GM software updates, specifically programmed to your vehicle’s unique VIN. This ensures seamless communication with all other modules and restores the performance you’ve been missing.
From the Diagnostic Bay: The Ghost in the Machine
I remember a 1999 Chevy Tahoe that came into my shop. The owner had been to three other places chasing an intermittent no-start and stalling issue. No one could find the problem because it would run fine for days, then suddenly die. After hooking up my scope, I noticed the 5-volt reference signal to the sensors would drop out randomly. This wasn’t a sensor or a wiring issue; it was a classic sign of an internal PCM failure. We swapped in a VIN-programmed PCM just like this one, and the ‘ghost’ was gone. The customer was thrilled to have his reliable truck back, and it was a reminder that sometimes the simplest solution is the right one.
Is Your GM Truck or SUV Showing These Signs?
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, this module is the likely fix you need. In my shop, these are the tell-tale symptoms I look for first:
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0605 (Internal Control Module ROM Error).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling, especially when coming to a stop or at idle.
- ✔ Noticeable decrease in fuel mileage.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ The anti-theft or security light stays on, preventing the engine from starting.
- ✔ Communication errors with your scan tool.
A Straightforward Guide to Your PCM Swap
One of the best parts about this solution is its simplicity. Because we program the module to your VIN before shipping, you won’t need a trip to the dealership. For most of the vehicles this fits, installation is a job a confident DIYer can handle in under an hour.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the PCM: On most of these GM trucks and vans, the PCM is located in the engine bay, often on the driver’s side fender or near the battery. It’s a metal box with several large wiring harness connectors.
- Disconnect the Harnesses: Carefully release the locking tabs and unplug the wiring harnesses from the old PCM. Inspect the connectors for any corrosion or damage.
- Remove the Old Unit: Unbolt the PCM from its mounting bracket. It’s typically held in place by a few small bolts.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and securely plug in the wiring harnesses. You should hear a ‘click’ as they lock into place.
- Reconnect the Battery: Re-attach the negative battery terminal.
- Perform Security Relearn: For many of these vehicles, you will need to perform a simple security relearn procedure (often called a Passlock or VATS relearn). This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This syncs the new PCM with your vehicle’s anti-theft system. Consult your vehicle’s specific procedure if needed.
Verified Compatibility for Your Vehicle
This PCM is a direct replacement for service number 09355699 and is compatible with a wide range of GM vehicles. Please verify your part number and match it to our list. This unit is a confirmed fit for the following models with the specified options:
BLAZER S10/JIMMY S15 98 (RH front engine compartment), w/o build date opt ZN4; ID 9355699
BRAVADA 98 (6-262, 4.3L), w/o build date opt ZN4; ID 9355699
CHEVROLET 1500 PICKUP 98-99 (Gasoline, LH front engine compartment), ID 9355699
CHEVROLET 2500 PICKUP 98-99 (Gasoline, LH front engine compartment), ID 9355699
CHEVROLET 3500 PICKUP 98-99 (Gasoline, LH front engine compartment), ID 9355699
ENVOY 98 (RH front engine compartment), w/o build date opt ZN4; ID 9355699
ESCALADE 99 (LH front engine compartment), ID 9355699
EXPRESS 1500 VAN 98-99 (ID 9355699)
EXPRESS 2500 VAN 98-99 (Gasoline), ID 9355699
EXPRESS 3500 VAN 98-99 (Gasoline), ID 9355699
GMC 1500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
GMC 2500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
GMC 3500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
ISUZU HOMBRE 98 (4.3L), w/o extended build date opt ZN4; ID 9355699
S10/S15/SONOMA 98 (4.3L), w/o build date opt ZN4; ID 9355699
SAFARI (GMC) 98 (LH front by battery), ID 9355699
SAVANA 1500 VAN 98-99 (ID 9355699)
SAVANA 2500 VAN 98-99 (Gasoline), ID 9355699
SAVANA 3500 VAN 98-99 (Gasoline), ID 9355699
SUBURBAN 1500 98-99 (Gasoline, LH front engine compartment), ID 9355699
SUBURBAN 2500 98-99 (Gasoline, LH front engine compartment), ID 9355699
TAHOE 98-99 (Gasoline, LH front engine compartment), ID 9355699
YUKON 98-99 (LH engine compartment), ID 9355699
This part also interchanges with the following part numbers: 16266645, 16250279, 16258815, 09366810, 9366810.
Frequently Asked Questions
Frequently Asked Questions
Do I need to do anything after I purchase?
Yes. After you place your order, you MUST provide us with your vehicle’s 17-digit VIN. We cannot program and ship the module without it. This ensures the PCM is a perfect match for your vehicle’s systems.
Is this a new part?
No, this is a high-quality, used OEM part that has been sourced from a salvaged vehicle. We inspect and test these units to ensure they are fully functional before programming them with the latest GM software for your vehicle.
Will I need to have this programmed by a dealer?
No. The main benefit of our service is that we handle all the programming for you. The module will arrive ready for installation and the simple security relearn procedure.
What is the security relearn procedure?
It’s a simple process that syncs the new PCM to your vehicle’s anti-theft system (VATS/Passlock). It typically takes about 30 minutes and only requires your ignition key. We include general instructions, but you can easily find vehicle-specific steps online.
What if my part number isn’t an exact match?
This PCM, 09355699, is interchangeable with several other part numbers listed in the description. As long as your vehicle is on the compatibility list and your original part number is one of the alternates, this module will work perfectly once programmed to your VIN.