Results 1 to 4 of 4

Thread: HP says MIL is off, it isn't. Also has a code not listed under engine diag...

  1. #1
    Tuner in Training
    Join Date
    Apr 2017
    Posts
    10

    HP says MIL is off, it isn't. Also has a code not listed under engine diag...

    I bought an 01 3500 silverado with an 8.1 in it. The previous owner had removed the Allison auto and installed an NV4500 manual trans. They couldn't make it run after the swap, and sold it to me cheap. I disabled VATS, changed the transmission drop down to manual, pasted a factory stick trans timing table from a repository tune in it and few other odds and ends. It runs and drives well, but the MIL is on with codes P0700, P0748, and P0778. HP says MIL status is off. The first two codes I have SES unchecked and no error reported in the drop down. The last one is not listed.. Also the message center says "trans hot idle engine" I'm assuming this is BCM controlled? I ordered a resistor to solder in the temp sensor wires to make make it think the trans is @160 but if anyone has a better idea I'm all ears. I did not do a manual trans segment swap, I have HP Tuned a couple of 5.3s with stick transmissions behind them with great success without a segment swap, but neither were in factory trucks with a BCM. I'm also wondering if the Allison TCM is playing some part in this. The truck is going to be a tow rig for me so I'd like to get the annoying lights off the dash.

    Thanks!

  2. #2
    I'm on the same boat right now and have no idea what to do for this lights to go away lol
    09 Pontiac G8GT LSA conversion & cammed (HP Tuned)
    07 Trailblazer SS Cammed & Nitrous Fed (HP Tuned)

  3. #3
    Tuner
    Join Date
    Aug 2016
    Location
    Swansea Wales UK
    Posts
    177
    Have a look in the trans diagnostic and look at the over temp requirements ?
    Gen3 L59/4L60E LS3 cast manifolds, Small Cam change, 2800 Convertor, MPVI, using MTX-L for wideband tuning

  4. #4
    Advanced Tuner
    Join Date
    Mar 2010
    Location
    New Orleans, LA
    Posts
    628
    submit a support ticket to get those codes added in
    decipha @ EFIDynoTuning
    http://www.efidynotuning.com/