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Throwing phantom codes....SES light flashing but no codes?

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Old Jun 26, 2003 | 10:10 AM
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Default Throwing phantom codes....SES light flashing but no codes?

When I was out tuning my car, my SES light was flashing even though I just turned off the only codes that cause my SES light to flash. Well, while the SES light was flashing, we autotapped it to see what codes it was throwing. Well, nothing registered.

This has been happening frequently lately where I throw no codes, but my SES light randomly flashes. Also, one of the times we pulled up a P0000 code with no explanation

My CPU has ghosts or something. Anyone else experience this?
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Old Jun 26, 2003 | 11:27 AM
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Default Re: Throwing phantom codes....SES light flashing but no codes?

verbs did you delete the misfire code P0300?

I get the same thing, what is happening in my situation is I deleted the P0300 code because I was getting alot of false misfires from the big cam. Well even though the PCM will not record the misfire because I told it not to, when it encounters too many misfires over a certain period of time like 5 seconds or something it will send a flashing SES.

In ATAP add Misfire History by Cylinder to your table. Make sure you are not getting real misfires.


Good Luck,
Lee
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Old Jun 26, 2003 | 11:49 AM
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Default Re: Throwing phantom codes....SES light flashing but no codes?

verbs did you delete the misfire code P0300?

I get the same thing, what is happening in my situation is I deleted the P0300 code because I was getting alot of false misfires from the big cam. Well even though the PCM will not record the misfire because I told it not to, when it encounters too many misfires over a certain period of time like 5 seconds or something it will send a flashing SES.

In ATAP add Misfire History by Cylinder to your table. Make sure you are not getting real misfires.


Good Luck,
Lee
Good call! Yes, I deleted the P0300 misfire code. I'll double check ATAP to make sure I'm not seeing real misfires.
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Old Jun 26, 2003 | 12:06 PM
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Default Re: Throwing phantom codes....SES light flashing but no codes?

Well, time to test that theory, turn off the misfire diag completely, not just P0300
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Old Jun 26, 2003 | 10:51 PM
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Default Re: Throwing phantom codes....SES light flashing but no codes?

You shouldnt completely disable the PO300 code, but instead desensitize the computer in edit at idle only. This way if there is a severe misfire while cruising, the computer will still be able to pick it up. I've done several PCMs this way and have never had an SES for a misfire unless there really was something wrong.
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