How to retrieve Check Engine Light Codes for older GM cars & trucks with only a paperclip... (OBD1) And if you searched for hours (like I did) simply for a good parts diagram page for this model truck - here's the best I found http://media.lmctruck.com/pdf/CD/cdComplete.pdf If you enjoy this free moto entertainment, racing, industry news, and DIY help page, please donate here - https://paypal.me/horsepowerhouse | Horsepower-House

GM OBD1 code 12? It means your engine's RPM signal isn’t detected during cranking. Common causes include a faulty crankshaft position sensor, defective wiring, or a malfunctioning ignition module. Haynes Manuals helps you diagnose and fix the problem step by step. Find your GM manual today at haynes.com. #HaynesManuals #HaynesShowsYouHow #GMRepair | Haynes Manuals