ECM trouble dtc 51 PROM error

[Schurkey]

Is Code 51 on your vehicle actually PCM/ECM issues?

 

[94GMCK1500]

Glad you asked... I have a PCM not an ECM... My bad... I did the test on the PROM/CAL just like the book said... I also disconnected the battery for 60 minutes while inspecting the PROM for dirt or bad or bent pins... It looked new still, which it's only 15 months old ... I tested the TPS with multimeter and found the numbers did move with little erratic but nothing major...I started it up, the check engine light off and ran little better... Disconnecting the battery again, replaced the TPS... Started up and drove it, drove better than before this all happen yesterday....

What I learned while checking up on the issue is that OBD1 code 51 is also a signal switch failure... Could also be something related to the A/C unit, guessing it depends on the year for this code... It also mentioned TPS being bad... My guy who deals with nothing but GM trucks for years said TPS after I told him the symptoms and the code... I learned something new and so far it runs far better than before... I'm replacing the plugs from copper nickel lawnmower spark plugs and dropping in some NGK Iridium after several people claims it made a difference so figured what the hell.... So that's pretty much where it stands as of right now.... Thanks everyone....