Is Your Late-90s GM Running Rough? It Might Be Time for a New Brain.
If you’re dealing with a 1998 Chevrolet Lumina, or another classic GM vehicle from that era, you might be chasing down some frustrating issues. Maybe it’s a transmission that slams into gear, an engine that stalls for no reason, or a check engine light that has become a permanent part of your dashboard. You’ve checked the sensors, you’ve looked for vacuum leaks, but the problem persists. As a technician with over two decades of experience under the hood of these cars, I’ve seen this scenario hundreds of times. More often than not, the culprit is a failing Powertrain Control Module (PCM).
“A customer’s 1998 Bonneville came in last week with these exact symptoms…”
He had a beautiful, low-mileage Bonneville with the 3.8L V6. He was at his wit’s end. The car would randomly refuse to shift out of first gear, and then, just as randomly, it would start working fine again. He’d replaced the vehicle speed sensor and a shift solenoid with no luck. I connected my scan tool and saw a slew of communication error codes. Experience told me this wasn’t a transmission issue, but a logic issue. The PCM, the computer that controls both the engine and transmission, was failing internally. We installed one of these pre-programmed modules, and the car drove off my lift shifting as smoothly as it did in 1998.
Common Symptoms of a Failing GM PCM (Part 9357440)
The PCM is the central command center for your engine and transmission. When its internal components start to degrade from years of heat cycles and vibration, it can cause a wide range of confusing problems. If your vehicle is on the compatibility list, look out for these signs:
- ✔ Harsh or Erratic Shifting: The PCM directly controls the transmission’s shift points and line pressure. A failing module can cause delayed engagement, hard shifts, or getting stuck in one gear.
- ✔ Engine Stalling or No-Start: The module controls fuel injection and ignition timing. If it fails, it can cut fuel or spark intermittently, leading to stalls or a car that cranks but won’t start.
- ✔ Persistent Check Engine Light (CEL): You may see codes related to internal module failure, communication errors (U-codes), or multiple random sensor codes that don’t seem related.
- ✔ Poor Fuel Economy: Inefficient engine operation due to incorrect fuel and timing calculations will cause your vehicle to consume more gasoline than usual.
- ✔ Failed Emissions Test: A faulty PCM can’t properly manage the engine’s emissions systems, leading to an automatic failure at the testing station.
The Solution: A VIN-Programmed, Ready-to-Install Module
In the past, replacing a PCM was a major job that always ended with a trip to the dealership for expensive programming. This module eliminates that step entirely. 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 Vehicle Identification Number (VIN).
How It Works:
- Place Your Order: Purchase this Powertrain Control Module.
- Provide Your VIN: After your purchase, send us your 17-digit VIN. You can usually find it on your driver’s side dashboard (visible through the windshield) or on your registration/insurance card.
- We Program It: Our technicians will use your VIN to load the correct, updated GM software onto the module. This ensures perfect compatibility with your engine, transmission, and options.
- Install and Drive: We ship the module to you. In most cases, installation is straightforward. Once installed, your vehicle will start and run correctly without any further programming. In some specific GM models, a simple security relearn procedure (often called a CASE relearn) may be required, which can be done without special tools.
Compatibility Information
This module, service number 9357440, is a direct replacement for several other part numbers, including 09356741, 16236757, 9356741, 9357034, and 9366314. Please verify the part number on your original module. It fits a wide range of 1998-1999 GM vehicles, including:
Chevrolet
- ✔ LUMINA CAR 98: Electronic Control Module; (LH engine compartment)
- ✔ MALIBU 98: Electronic Control Module; 6-191 (3.1L)
- ✔ MONTE CARLO 98: Electronic Control Module
- ✔ VENTURE 98: Electronic Control Module; (6-207, 3.4L)
- ✔ CAMARO 98: Electronic Control Module; 6-231 (3.8L)
Pontiac
- ✔ GRAND AM 98: Electronic Control Module; 6-191 (3.1L)
- ✔ GRAND AM 99: Electronic Control Module; (LH center dash), 3.4L (ID 16236757, 9356741, 9366314, 9357034, 9347440)
- ✔ GRAND PRIX 98: Electronic Control Module
- ✔ BONNEVILLE 98: Electronic Control Module
- ✔ FIREBIRD 98: Electronic Control Module; 6-231 (3.8L)
- ✔ TRANS SPORT 98: Electronic Control Module; (LH engine compartment)
Buick / Oldsmobile
- ✔ CENTURY / REGAL 98: Electronic Control Module
- ✔ LESABRE / PARK AVENUE / RIVIERA 98: Electronic Control Module; (6-231, 3.8L)
- ✔ SKYLARK 98: Electronic Control Module; 6-191 (3.1L)
- ✔ ACHIEVA 98: Electronic Control Module; 6-191 (3.1L)
- ✔ ALERO 99: Electronic Control Module; (LH center dash), 3.4L (ID 16236757, 9356741, 9357440)
- ✔ CUTLASS 98-99: Electronic Control Module
- ✔ EIGHTY EIGHT 98: Electronic Control Module
- ✔ INTRIGUE 98: Electronic Control Module
- ✔ SILHOUETTE 98: Electronic Control Module; (LH engine compartment)