The green plugs are called Test Mode Connector and are used for the "D
Check" which gives trouble codes through the check engine light. When
used in conjunction with the black plugs will clear all codes from
memory.
The black plugs are called Read Memory Connector and are used to check
past trouble codes, blink the vehicle specification code (type of
vehicle) and possibly other functions we don't make use of. They will
also clear codes in the computer when used with the green plugs. The
code clearing procedure will clear all memory functions which the
computer will have to relearn as you drive for a while. I believe the
computer memorizes all its functions and constantly averages how it
responds to input from all the sensors based on past actions. In other
words it works just like our brain does.
With the black plugs only connected you may get a blinking light with
the ignition on but engine off. This is either a trouble code from
memory or the Subaru veh identification code if there are no codes in
memory.
The test procedures for both sets of plugs is listed in the fuel
injection manual which should be on the web link that has been posted
twice by Darrell.
Basically to test for trouble codes you connect the green plugs, turn
the key on, depress the acc pedal all the way and immediately back off
to half throttle for two seconds then let up.
Then start the engine. This may cause the check engine light to emit
trouble codes. (Didn't on mine)
If not, drive down the street for one minute and shift through all
gears. This should cause the check engine light to emit trouble codes.
(I got codes half way through this process). Then it says to "warm up"
the engine above 2000 rpm. The book notes that over 2k for more than 40
seconds will produce a trouble code but it doesn't say which one or
whether you are supposed to stop or continue beyond 40 seconds.
If light blinks in a non trouble code sequence you are done with the
test but should be scratching your head because you should have at least
the codes for the each of the "big three" items you have not done a
Myers patch for.
If light is not blinking at this point you should go back through the
2000 rpm warm up again.
I got the big three codes both in my test and from a dealer who used the
Select Monitor plug. The Select Monitor is a hand held device that can
check all the codes, including those the D Check doesn't pick up. It
can also clear the memory.
