Cosi

Ive read you need to switch the key to ON and short out two terminals on the diagnostics plug in order to put a car into diagnosis mode. Unfortunately I dont have a diagnosis plug anywhere on my loom... The car is a KP61, rear wheel drive starlet, that I am half way through installing a 4AGE and T50 from a Trueno AE86. Ive got the original loom. Ive wired up a check engine light but cant figure out what to do about getting it into diag mode.