Check engine light possible causes

Discussion in 'Fox 5.0 Mustang Tech' started by 50atheart, Feb 21, 2013.


  1. 50atheart

    50atheart New Member

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    I've pulled the codes in both key on and engine on and it comes out clean. When I drive I get a check engine light almost non-stop. Any ideas on a cause? 89 5.0 AOD with a low rpm cam
  2. jka

    jka Member

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    What do you mean?...it comes out clean..Are you getting any codes? like code 11 or just nothing.
  3. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    No code 11 (two flashes when the computer dumps the codes)? A perfectly functioning system will always get a code 11, it is the everything is OK code. The 11 code is computer passed its internal self test.
    If you don't get an 11, you have computer or wiring problems.
    Please check and repost.
  4. 50atheart

    50atheart New Member

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    Sorry for being too brief. Yes, I meant that I went through the KOEO and had no error codes, just the 11. I also ran the ER tests and only got the 90 after the cylinder test. Still I get a check engine light intermittently when driving. When I stop, I run the KOEO and back to 11 and no error codes. Could I have a loose wire to the EEC? or maybe bad memory? Can't seem to find a way to find a cause.

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