Question

1997 Honda Accord EX 2.7L V6 P1786, how to fix code P1786?

Answer 1

P1786 Transmission system problem

This is  communication code condition between the ECM and the TCM, 3 things to consider for the fix  there is a open line between the TCM and ECM, the 2nd, the ECM is faulty, 3rd the TCM is faulty, Honda calls this code condition a open or short in the FAS wire (Force auto stop). In this diagram check the continutity between the ECM and TCM The fix is more than likely another TCM

Answer 2

P1786 HYUNDAI Code - Engine RPM Output Circuit Malfunction

Read more: https://www.autocodes.com/p1786_hyundai.html