Fitment notes: Diesel engine requires high CCA rating; side post terminals standard on GM trucks of this era
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Every control module on the 1987-1989 Chevrolet K20 — 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.
⚠️ Physical PROM chip must be transferred from old ECM or replaced with correct calibration. TBI (Throttle Body Injection) standard on most models by 1987. Carbureted models have no ECM.
Transmission Control Module (TCM)0.9 hr R&Rrelearn only +0.3 hr700R4 (4L60) automatic transmission with electronic control▸ programming details
📍 passenger side interior kick panel or under passenger seat
🔧 drive cycle relearn
⚠️ Early electronically controlled overdrive automatic. Most K20 trucks still used hydraulic-only TH400 or manual transmissions without TCM.
Electronic Spark Control Module (ESC)0.6 hr R&Rno codinggasoline engines with ESC knock sensor system
📍 driver side firewall near brake booster
⚠️ Non-programmable knock control module, separate from ECM on equipped models.
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 1988 Chevrolet K20 6.2L V8 Diesel and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Mechanic · 20+ years.