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Thread: Reading ABS fault codes

  1. #1

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    Default Reading ABS fault codes

    Did this on my car, a MY98 Legacy RS-B (BD) EJ20R.

    Based on the fact that GC/GF CEL codes are read more or less in the same fashion as BG/BD's (IIRC???), I'm going to say it's a fairly accurate assumption that ABS codes are read the same between models as well, but don't quote me. Can't say for sure having never even taken much of a look at a GC/GF engine bay, nevermind the nitty gritty behind the dash.

    Had my yellow ABS light come on a little while ago. Did some research and came across this on the UKLegacy forums (where they get all the info they have, I don't know...!)
    Anywho, this quote pretty much sums up exacty the steps I followed and what to do, perfectly;

    I copied this for somewhere ages ago, its from a LHD car . In a rhd car the plug is above the footrest area ish

    If your ABS light is on the ABS computer will store an error code, much like the ECU. You can read what each code is with a simple procedure. Here it is (98 legacy GT wagon)

    Under the dash, above and to the left of the gas pedal there is a large bundle of wires. Remove the plastic panel below the steering column to make finding it easier. Look carefully, there should be a small (1/2 inch), BLACK plug hanging down from that bundle. On mine the plug was taped to the bundle, look carefully, it took me 1/2 hour just to find mine because I didn't know exactly what I was looking for. The documents I read said the plug is green, on my car it is in fact black. There are wires with two small metal prongs taped to the wire connecting to the plug. The prongs may be taped up and not visible (as was in my case) or may be hanging next to the plug already, expose the two prongs.

    Looking at the black diagnostic plug, it has two holes on top and four on the bottom, like so:
    ____X X
    __X X X 6

    The X's are the holes you don't care about and the six being the hole you do care about. With the key in the OFF position, plug one of the metal prongs into position 6, the bottom right one as you are looking at the plug.

    Turn the key to the "ON" position, and observe the ABS light. It should start flashing at you, a long flash is for the tens value, the short flash for the ones value. It will always flash code "11" as the default code regardless if there is a problem or not (one long flash followed by one short one) In my case it flashed code 11 and code 21 (two long flashes and one short one) with a short pause between each code. the codes repeat for five minutes so just take your time and count the flashes several times to confirm you have the correct code.

    Trouble code list:

    Code Indicates

    None: Problem in light drive circuit. Light has to come on for 1.5 secs after ignition is on.

    Light On: Same as above

    11: Start Code
    21 FR wheel sensor open circuit or input voltage too high
    23 FL
    25 RR
    27 RL

    22 FR wheel sensor when no open circuit or speed signal input
    24 FL
    26 RR
    28 RL

    29 Faulty tone wheel
    31 FR Faulty solenoid valve circuit in hydraulic unit
    33 FL
    39 Rear wheels
    41 Faulty ABS control module
    42 Source voltage is low
    51 Faulty valve relay
    52 Faulty Hydraulic Motor and or motor relay
    54 Faulty Stop Light circuit
    56 Wrong control module used or faulty G Sensor

    In my case, I looked at the wheel sensor and the connecting wire for damage. There was none so I traced it to inside the engine compartment to find it....unplugged!!. :smt011

    In my case I reconnected the plugs for the wheel sensor and the code went away. If the code does not go away, take the prong that is sticking into the diagnostic plug and remove it and plug it back in three times in quick succession. That supposedly clears the code. The computer only stores three codes at a time so make sure that when you are done you only get code 11.
    My vehicle's connector used to read the codes was black also, and also had the two bare prongs taped along side within the bundle. Wasn't all that hard to find honestly.

    I found using either one of the two prongs allowed me to read the codes

    I would be careful to not plug the prongs ino the wrong socket; who knows what those other sockets in fact do.

    To reset the codes I found rapidly sticking either one of the two prongs in and out of the socket whilst looking at the dash for the ABS light to go out (reset) worked for me, not necessarily (3) times quickly, in and out. (...Do I make the joke???... )

    I can post photos of my vehicle as reference if anyone needs them.

    Hope this helps!!!
    '98 USDM 2.5GT BD5 EJ25D - Subaru heaven
    '98 JDM RS-B BD5 EJ20R - Current beast

  2. #2

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    Very interesting and useful so basically it sounds like the early GC8 Impreza for reading engine codes at least where there are two black connectors that you stick together and then you get flashed codes.

    Please post photos if you can as they always end up helping someone out.

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