The Candi Module should not plugged into your GM Tech 2 unless you’re working on a later car ..generally 2005 plus. Olders car from 96 should NOT have the Candi Module attached. OBD I only has 1 ground, so 12 pin adapter connects signal and chassis ground to the Tech 2 cable. OBD II has chassis and signal ground and they are connected in the cars wiring. How I was trying to get GM TECH2 CANdi module to work: Nothing on CANdi end of cable. ...
gm-tech2-scanner-1 Tech II Diagnostic Scanner (Works with GM/SAAB/OPEL/SUZUKI/ISUZU/Holden) with candi Module interface and 32 MB Card. Scanner comes with GM English Card as default, Covering GM Cars and Trucks GM-English 33.004 1991-2013 (Latest software). DOES NOT come with storage case. Not an authentic tech2. If you're looking for an authentic tech2 expect to pay $1,000+ for a used one and you better know how to tell the difference ...