How to Pull Your Codes WITHOUT a Scan tool!

Discussion in 'Tech Articles, How-To's & Write Ups' started by ryclef331, Apr 1, 2007.

  1. ryclef331

    ryclef331 Well-Known Member

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    So your Mustang's check engine light is ALWAYS on? Thats great is when you want a tan but can be bad news if something is really wrong with your engine. I'm going to show you how to pull the codes YOURSELF using just a piece of wire and a test light or a analog voltmeter. NO SCAN TOOL and NO PARTS STORE PIMPLE FACED CLERKS!


    Here's how.

    Any Chilton or Haynes Manual will show you how to do this but if you don't have that...then this is free.

    Where to hook up.
    STARTING WITH THE KEY OFF!!!
    Locate the test port under the hood. Its on the passenger side firewall, behind the strut tower. This is how you should wire it up.
    [​IMG]

    There will be two plugs...One large and shaped like a trapezoid and the other small and grey. Take a piece of wire and stick it in the port labeled #2 on the above pic and run it to the smaller plug. This is your jumper wire. Next with either your analog voltmeter or test light, plug the negative probe into port number 4 and the other should go to the postive on the battery.

    Thats it...now you're ready to pull codes.

    There are 3 types of codes.

    Fast Codes - Codes that are flashed out 100 times faster that normal and can only be picked up by a Scan tool. You won't even notice these.

    Self Test or Hard Codes - These are codes that are PRESENT at the Time of testing....like something is wrong WHILE you're pulling the codes.

    There is also a Seperator Code. This is "111." This will flash when the car is done showing the initial Hard Codes and is about to throw out Soft Codes.
    "111" is NOT a trouble code!

    Continuous Memory Codes or Soft Codes- These are STORED codes. These are 3 digit codes. This is stuff that is stored in the ECU even after you've shut the car off. Like you were driving to work and the light came on. When you left work the CEL is gone but the computer has stored it. These are chronic codes or intermitent.

    You can read the codes from two different points. You can sit and stare at the sweeps of the voltmeter's needle/ test light blinks....OR you can count the flashes of the Check Engine Light. I prefer the CEL. Codes are spit out kind of like Morse Code. The best thing to do is have a blank sheet of paper and a pen handy to right down the numbers b/c you're going to be counting flashes. For example....for code 123. The needle on your voltmeter will sweep and the CEL will blink ONCE, then pause for 2 seconds, then sweep/blink TWICE, the pause for 2 seconds, then sweep/blink THREE times. There will be a 4 second pause between codes and then it will spit out the next code in the same manner.

    There are TWO ways to pull codes. You should perform each when pulling codes.

    Straight out of the Haynes manual

    "The diagnostic codes for the EEC-IV systems are arranged in such a way that a series of tests must be completed in order to extract ALL the codes from the system. If one portion of the test is performed without other, there may be a chance the trouble code that will pinpoint a problem in your particular vehicle will remain stored in the PCM without detection. The tests start first with a Key On, Engine Off (KOEO) test followed by a computed timing test then finally an Engine Running (ER) test."

    Basically, if you skip some of the following steps...you MIGHT be missing something.






    Make sure the engine is up to operating temp.

    Turn off the car for at least ten seconds (use this time to hook up your jumper wire and voltmeter/test light).

    The the KEY ON (DO NOT START THE CAR!) and watch the needle on the voltmeter or the CEL.

    To do this...just turn the key to ON but do not start it. (MAKE SURE ALL ACCESSORIES LIKE A/C, LIGHTS, RADIO, ETC are OFF!)

    First up are the KOEO codes aka "hard codes."

    Count the flashes! Write down what you see!

    Then wait for "111"

    Now it will throw out the "soft codes"

    Count the flashes! Write down what you see!



    NEXT UP is the Engine Running Codes!


    Again with the Engine at Operating TEMP, shut the engine off for 10 seconds.

    Hook up the Jumper wire and voltmeter/test light.

    This time the car will flash the ENGINE ID Code. This is HALF the Number of cylinders. 4 flashes for a V8 and 4 for a V6.

    Within 1-2 seconds of the the ID code turn the steering wheel 1/2 turn and release. This will store any powersteering codes.

    Push the Brake Pedal and Release. DO THIS IMMEDIATELY AFTER THE STEERING WHEEL CHECK.

    Some Cars will ask for a "goose" code. The car will request this by flashing the CEL or Voltmeter sweep ONCE right after the Brake/steering test. Theis means QUICKLY stab the throttle to the floor and release. DO NOT DO THIS unless you see the ONE FLASH!

    The next part of the test is the timing advance test.

    (It is now 6:30 am and I'm going to bed. I will continue this article when I have the time. Sorry to leave y'all hanging but I've got a long day of working on a vette tommorow. LATER!

    Ry)
     
  2. KELS94GTVERT

    KELS94GTVERT New Member

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    love this write up it realy worked :banana:
     
  3. 916_5.0

    916_5.0 Active Member

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    Very nce write up the diagram pic helps a lot it makes it very clear well done.
     
  4. Jayde

    Jayde New Member

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    Cool
     
  5. badass98svt

    badass98svt Well-Known Member

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    Very nice write-up.
     
  6. Sir Charles

    Sir Charles New Member

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    Excellent write up.
     
  7. Dekorum

    Dekorum New Member

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    For how many days can the ECU store previous codes?
    Do O2 codes come up in KOEO or do I have to do engine running to see if there are any codes about my O2s.
    Also, can I just stop after KOEO.. like once its done reading the codes in that mode, close my TEST EEC thing behind the shock tower up and use the car like normal. Or do I have to complete the whole entire engine running mode and such?
     
  8. CanaryGT

    CanaryGT Well-Known Member

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    Nice Write up..
     
  9. portalz

    portalz New Member

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    What about an intermittent check engine light? Thanks.
     
  10. ryclef331

    ryclef331 Well-Known Member

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    See the original post where it talks about "soft" codes....they ARE stored until you clear out the ECU.
     
  11. d_punch

    d_punch Active Member

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    so RY whatever happen to finishing this write up?

    leaving us hanging like this is a crime.

    :help2:
     
  12. realitygt

    realitygt Legend

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    pretty awesome , I prefer to go up to autozone or advance auto and let them do it for free, but still a really nice post!
     
  13. BlackCobra50

    BlackCobra50 Well-Known Member

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    Just reading through and I noticed that ryclef is still leaving us hanging on the timing advance test... lol
     
  14. godsrods

    godsrods New Member

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    the obd II cars can't be read like this. and remember that the codes are most of the time just a symptom of a different problem .ALWAYS find the cause of the problem first and then repair as needed.