Is Your 1998 Bonneville or GM Vehicle Running Rough?
If you’re dealing with frustrating issues like unpredictable stalling, poor fuel mileage, a persistent check engine light, or harsh transmission shifting, the problem often points directly to a failing Powertrain Control Module (PCM). As the central computer for your engine and transmission, when the PCM starts to fail, it can create a cascade of confusing symptoms. I’ve been diagnosing these GM vehicles for over 20 years, and I’ve seen countless owners replace perfectly good sensors and fuel pumps, only to find the root cause was the PCM all along.
Expert Pro Tip from a 20-Year Veteran Technician
Before installing your new PCM, take a moment to inspect the harness connectors. On vehicles of this age, it’s common for pin-fitment to loosen or for corrosion to build up, causing poor contact. I recommend using a small amount of electrical contact cleaner on the vehicle’s harness plugs. A clean, secure connection is critical for the new module to function correctly and can prevent a host of intermittent issues down the road.
The Direct, Reliable Solution: Programmed and Ready to Install
This isn’t just a replacement part; it’s a complete solution. We take a quality-tested PCM and flash it with the latest official GM software calibration specifically for your vehicle. All we need is your 17-digit Vehicle Identification Number (VIN) after you place your order. This critical step ensures that the module communicates perfectly with your car’s specific systems, from the engine and transmission to the anti-lock brakes and security system. By handling the programming for you, we eliminate the need for an expensive trip to the dealership for software flashing.
Key Symptoms This 1998 Bonneville PCM Corrects:
- ✔ Unexplained stalling or engine cutting out
- ✔ Failure to start or intermittent starting problems
- ✔ Erratic or harsh automatic transmission shifting
- ✔ Drastically reduced fuel economy (MPG)
- ✔ Check Engine Light (CEL) with various communication or sensor codes
- ✔ General poor engine performance and hesitation
Simple Installation Process
You don’t need to be a master mechanic to install this part. With basic hand tools, you can get your car back on the road quickly. While the exact location can vary slightly by model, the process is straightforward.
- Safety First: Always disconnect the negative terminal from your car’s battery before starting any electrical work.
- Locate the PCM: On most of these GM models, the PCM is located either in the engine bay (often inside the air filter box) or under the dashboard on the passenger or driver’s side.
- Disconnect and Remove: Carefully unplug the electrical harness connectors. They have locking tabs that need to be released. Once disconnected, unbolt the old module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed PCM into place. Firmly reconnect the harness connectors, ensuring they click and lock securely.
- Reconnect Power: Reattach the negative battery terminal. Your vehicle is now ready to start. In some cases, a security relearn procedure may be necessary, which can typically be done without special tools.
Guaranteed Compatibility & Part Number Information
This module is a direct replacement for a wide range of GM vehicles and is guaranteed to be compatible with the following service part numbers. Please match your existing part number to this list to ensure proper fitment.
Compatible Service Numbers: 09356741, 16236757, 9357034, 9357440, 9366314
This part will fit the following makes and models with specified options:
ACHIEVA 98 (3.1L), ALERO 99 (3.4L), BONNEVILLE 98, CAMARO 98 (3.8L), CENTURY 98 (3.1L), CUTLASS 98-99, EIGHTY EIGHT 98, FIREBIRD 98 (3.8L), GRAND AM 98-99, GRAND PRIX 98, INTRIGUE 98, LESABRE 98 (3.8L), LUMINA CAR 98, MALIBU 98 (3.1L), MONTE CARLO 98, PARK AVENUE 98 (3.8L), REGAL 98, RIVIERA 98 (3.8L), SILHOUETTE 98, SKYLARK 98 (3.1L), TRANS SPORT 98, VENTURE 98 (3.4L).