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94 subaru legacy code 51

11-26-2006, 08:31 PM
My 94 legacy really has troubles starting in cold weather, with a steady check engine light. Have been unable to pull a diagnostic code. Today I connected the green T diagnostic connector and finally got a code. 5 long flashed and 1 short flash, which I read as a 51. This code says it is a neutral switch. Guess my question is what is a neutral switch and how does it affect cold starting and the check engine light. Have been unable to locate anything on this switch. Thanks for the help.

11-26-2006, 09:09 PM
IIRC correctly the 'neutral switch' is a switch which has to be made for the engine to be allowed to fire.

Basically, on an auto trans all it is really is a position sensor on the shifter which tells the computer the car is in neutral and it can crank the engine.

But, if you're getting a 51 you're a manual transmission, which means it's a clutch depressed switch or similar.
It may be a result of moisture build up that you're getting this since moisture buildup is more likely in cold weather.

I will do a little more digging to see if I can get you more information since right now I am speculating based on what I know about the older transmissions.


The info I found indicates the pre-'98 Legacy doesn't have the switch on the clutch, the neutral switch is on the shifter. Now I will see what I can find out for you about the actual location of said switch.

One question, is your car garage kept?

EDIT 2: Switch is located on transmission.

11-26-2006, 10:04 PM
Forgot to mention it is an automatic tranny. The only way I got the code to post was to connect the green T connector and drive the car. When it's cold I will sit there for 5 minutes trying to start it. When it finally does it lops really dab and if I get on the gas it will die. I have to give it a few minutes then I'm good. In warm weather really no problems, still slow to start but not as bad as cold weather. With winter coming, in Texas, I need to fix this or my starter is going crap out or battery.

11-26-2006, 10:05 PM
Picked the car up from my parents, who live in Pittsburhg, PA and it was outside most of the time.

11-26-2006, 10:19 PM
According to the info I have, only a manual transmission can throw a code 51, that said, if it is the neutral switch, it's still located on the transmission, so you should be able to find it pretty easily.

There are 2 switches that will be located on the transmission, the second is for the cruise control (if you have it), so don't ruin that one ;)

11-27-2006, 03:23 AM
Thanks for the help and input.

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