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Reading OBD-I Codes via Check Engine Light

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Old Oct 17, 2004 | 09:43 PM
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Default Reading OBD-I Codes via Check Engine Light

http://www.troublecodes.net/Porsche/ has some information that may be for 1995 993 owners. Here is the gist of it:

Diagnostic trouble codes may be read through flashing of the "Check Engine" lamp.

1. With engine off, turn ignition switch to the "On" position.
2. Depress the accelerator pedal completely for 3-5 seconds.
3. Wait for the "Check Engine" lamp to flash, then release the accelerator pedal. The lamp will begin to flash diagnostic trouble codes.
4. Fully depress the accelerator pedal to display the next code.

To reset:

1. With engine off, turn ignition switch to the "On" position.
2. Fully depress the accelerator pedal for more than 11 seconds.

Following this procedure, I got one long blink, pause, one short blink, pause, five short blinks, then the cycle repeats. I think this is DTC 15, but after looking at the code charts on the website, I'm not sure what it means. Anyone have an idea?

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Old Oct 18, 2004 | 09:01 PM
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Still looking for help on this one...

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Old Oct 19, 2004 | 05:11 AM
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Interesting. Sorrry I don't have an answer, but I was wondering if there is also a manual way of reseting codes, rather than taking a trip to the dealer (ie to turn the airbag light off).
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Old Oct 19, 2004 | 08:01 AM
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Out of my own ignorance-is there an OBD I reader? I see OBD II readers advirtised at VIP Auto all the time but haven't seen one for the OBD I.

TIA

Al
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Old Oct 19, 2004 | 10:24 AM
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OBD-I reader is available from the dealer - several thousand $$$$ far as I know.

If you are REALLY reading DTC 15, shop manual sez "throttle potentiometer". Want more info - buy the shop manual, cheapskate.
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Old Oct 19, 2004 | 11:36 AM
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Interesting. I had no idea that you could do this. I am off to my garage to try it. Thanks for the info.
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Old Oct 19, 2004 | 11:55 AM
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Sorry for the nOOb question, but how do you get info like "DTC 1123" from just a blinking light ?!?! What am I missing?
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Old Oct 19, 2004 | 12:04 PM
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I thin 1123 would display as 'flash, pause, flash, pause, flash, flash, pause, flash, flash, flash'. I assume a zero is a long flash.
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Old Oct 19, 2004 | 12:10 PM
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Okay. Back from the garage. I am getting the same code on my car. 1...15, then it resets with a long lamp... then repeats. In my manual, which I purchased at great expense, (so the Rays of the world don't get upset...) the code indicates "Injection valve- fault code for cylinder 1" There is a test procedure for doing evaluating the injector.

Eric, good question. The lamp stays lit a long time to indicate that it is starting a new code, then blinks the first, then second, digit in succession. It takes a couple of cycles to get the hang of it. For the 1_15 code, I got LONG, pause, short, pause, short, short, short, short, short then the cycle repeats. I may try to cause a fault just to see what mutliple codes look like. Anyone have more than one fault?

Incidentally, I tried the reset procedure and was unsuccessful. This would make sense if I had a bad injector... I may pull injector 1 and have it tested after I test the wiring.

Great thread. Isn't this board a wealth of info?!
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Old Oct 19, 2004 | 12:42 PM
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Another update. I would be careful about using the codes from the BAT website. They seem to be a little different from the 89-94 manual. (Which includes 94-95 OBDI for 993s....) The four-code list is WAY off the mark. The two-code list is closer, but if you get a fault code, ask a Rennlister before you panic and spend $$$ or tear into it yourself. Just my 2 cents worth.
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Old Oct 19, 2004 | 02:27 PM
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i have a bosch kts 300 that will pull codes and reset and diagnose all system that i would like to sell . if interested will consider all reasonable offers. have cable and unit is complete and in excellent condition.
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Old Oct 19, 2004 | 03:17 PM
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dutchcrunch, PM me with the details and price. Thanks
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Old Oct 19, 2004 | 03:26 PM
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Thanks for your contributions, especially Ray. Maybe he also knows where to buy the shop manuals, as the usual sources are all "NLA"...

BobbyT
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Old Oct 19, 2004 | 04:57 PM
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I gave this a go tonight, but no joy - does that mean that I actually have OBD II on my 1995 UK spec 993 cab ? Did the UK go OBD II earlier than the US ? How can I tell for sure what I have - couldn't find a label under the hood, and the cover just has 'OBD' on it ?
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Old Oct 19, 2004 | 05:59 PM
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I would suspect that you have no faults registered. I assume that if there are no codes in memory, this procedure would do nothing. If your cover says OBD it is OBDI- the OBDII covers have "OBDII" written on them. As to when they switched over the UK cars to II... I have no idea. Can anyone chime in here?
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