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Thread: 4L80 acting weird AFTER adding wire for TCC

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    Fuel Injected! CDeeZ's Avatar
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    May 2012

    4L80 acting weird AFTER adding wire for TCC

    I have been driving my 4L80 around without the TCC wired up. Last night, I wired in the TCC.

    I swapped in the 7427 PCM in this truck a few years back and everything was ok then.
    I also wired it just as is described in the conversion thread here:

    The truck USED to have a 700R4 so when I swapped in the 7427 a few years back I put the Orange wire from the brake switch to pin E13 at the PCM: E13--------Orange-----------Battery (Inputed in place of Brake Switchfor TCC to function)

    Now last night I started tracing the Purple wire from the brake switch and found that it in fact does go to a diode module under the dash for the ABS system. I deleted the ABS system on this truck... So what I did was i cut the one purple wire going FROM the brake switch TO the ABS diode module and I pinned that purple wire into pin E13 in place of the orange wire that WAS there.

    This trans has worked flawlessly so far, albeit running without the TCC functioning. There is a big cooler setup on it that I borrowed from a SuperDuty F250 or F350 so I don't think it was ever getting very warm.

    Took it out for a test today and it felt weird like either the converter was locking and unlocking -AND/OR- the trans was hunting between 3rd and 4th gear.... BEFORE I captured the log I'm posting, I was driving and when the TCC locked in what I think was 3rd gear, I could tap the brake switch and make it unlock/lock like you would expect. However, I soon realized an issue, which I DID capture with the attached log.

    If you start this log at 44 seconds in you can then shortly thereafter see it hunt between 3rd and 4th and it even loses the data stream connection at least once around this time also.......

    In this trans ADX the TPS shows 22%, but if I switch back to the regular ADX, the non transmission one it shows what the TPS ACTUALLY IS, which is nowhere near 22%, more like 0% or 1.2% max (my throttle is a bit sticky lol) COULD this ADX be screwed and the erroneous TPS reading be causing this issue????

    I have been scanning the trans using the
    A220 Trans1 $0E TP5 v250.adx.... The 2nd one doesn't seem to offer much or do anything?

    I found this thread where Billy is talking about no using the brake switch for the TCC (post #3):

    ANd this one where Dave is talking about a relay???? I thought the relay was only for if you are swapping from 4L60e to 4L80e??? (post #16)
    Attached Files Attached Files
    Last edited by CDeeZ; 02-10-2019 at 12:38 PM.

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