Every control module on the 1981-1996 Chevrolet G-Series — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
Vehicle Anti-Theft System / Pass-Key Module (VATS)2.5 hr R&Rrelearn only +0.5 hrwith VATS Pass-Key I system (optional 1991+)▸ programming details
📍 integrated within steering column lock housing
🔧 10-minute relearn procedure or GM Tech 1
⚠️ Resistor pellet in key must match module resistance value. Replacement requires 10-minute theft deterrent relearn (three consecutive 10-minute wait cycles).
Electronic Brake Control Module / ABS Control Module (EBCM/BPMV)1.5 hr R&Rrelearn only +0.3 hrwith rear-wheel ABS (RWAL) 1992+▸ programming details
📍 left frame rail ahead of rear axle, integrated with brake pressure modulator valve
🔧 GM Tech 1 or drive cycle
⚠️ Rear-wheel anti-lock only; requires brake bleeding and sensor relearn after replacement.
Instrument Cluster / Digital Instrument Panel (IPC/DIC)1.5 hr R&Rno codingelectronic/digital cluster models (optional on 1990+ Sportvan/Beauville)
📍 behind instrument panel bezel, center of dashboard
⚠️ Analog mechanical clusters are non-electronic and not listed. Electronic versions communicate via Class 2 data line (1991+).
📍 passenger side firewall, below cowl panel, mounted on inner fender well
🔧 GM Tech 1 or PROM chip replacement
⚠️ Early 1981-1986 models used replaceable PROM chips for calibration; 1987+ used serviceable MEMCAL. Carbureted engines through 1986 had no ECM.
Sensing Diagnostic Module / Diagnostic Energy Reserve Module (SDM/DERM)1.0 hr R&Rno codingwith dual front airbags (1995-1996 only)
📍 under center of dashboard, above transmission tunnel
⚠️ Battery must be disconnected 10+ minutes before removal. SRS light will self-clear after successful installation and ignition cycles.
Radio / Entertainment System (Radio)0.5 hr R&Rno coding
📍 center of dashboard, in radio mounting cavity
⚠️ Standalone unit; no integration with other modules. Theft-lock feature on some 1995-1996 radios requires dealer unlock code after battery disconnect.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 1971–1996 Chevrolet G-Series 5.0L V8 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.