So I've got 4th gear hunt on my truck.  It is intermittent.  I've had the alternator tested every which way and it always comes out good, be it bench testing, on car etc.  It's also pretty new.  I've gone ahead and done that ATS fix to bypass the ECM, but immediately threw a p0123.  I did an apps reset, tried to clear the code and still there.  Truck runs ok, but I'm at a loss.  I'm supposed to roll out for my trip on Sunday.  Any thoughts?

 

 

I still say skip the ATS bandaid. 99.9% of the time it's still the alternator.

Well the alternator is only 6 months old.  I've never had any reason to suspect it.  Per your usual recommendation, I've had it bench tested twice, once at a chain store, and once at a old school alternator shop, both said it was good.  Tested it on the car for AC and got .025v.  The shop actually disassembled it and checked all components on it too.  ATS is already done.  Really just hoping to figure out why I'm throwing the code now. 

Was the truck test drove with the alternator disconnected?

 

As for new alternators the do fail out of the box. I've seen 4 in a row fail out of the box. It's also possible for a diode to lose a good solder joint and intermittently surge AC noise.

 

As for APPS shift mods (filters) it still suggest against them. They truck ran for over 12 years without it. It means there is something failed still and adding a module or filter is a bandaid cover up. As for the error code you creating a short to ground or a short to 5V basically creating the error code (P0122 or P0123) so if the APPS signal is within span then no codes.

what ever is causing the codes is causing your4-gear hunt, either Bad APPS OR wiring issue.. I would try checking your ground connections for your APPS AND PCM... i had a issue of 4-gear Hunt bout 2-months ago.  i just happened to notice that the braided GND wire strap from the PCM mounting Screw was going up to the firewall and that screw WAS corroded with green corrosive..and the terminal end was almost into, 50% at least.

  I WAS not SURE  and am still not sure if this was the way it came from OEM or someone done it prior to me getting the truck, but it didn't look right to me so i made a new 10 ga. wire lead w/soldiered ends and ran it to negative battery lead post on inner fender beside passenger battery. this is the same as direct to BATT- cause theres a lead on this same post that goes to battery terminal..

 

   FIXED MY PROBLEM INSTANTLY,, SO IM GONNA AGREE WITH MIKE, KNUCKLE DOWN AND FIND THE PROBLEM AND FIX IT FOR GOOD,,THESE BAND-AID FIXES USUALLY DONT WORK FOR VERY LONG AND POP BACK UP WHEN YOU LEAST EXPECT IT.

I'm going out of my mind here.  We are supposed to get on the road Sunday, and now I've got the code that won't go away, and now it wont shift into 4th or lock up.  Wife's going to KILL me if this isn't sorted out ASAP.  Mike I might give you a buzz if that's ok a bit later after I try and undo what I did today.

 

I DID replace all my battery cables etc.  I'll check the PCM cable.

Edited July 3, 201510 yr by Nates1999

did you just tap into the orange/bl and the black/tan wires or did you cut them into???

Seams like I've heard of this happening before with type of fix only another company, Sun coast IIRC. can't remember what exactly went wrong but seams it was a step in the wiring they missed

I did it exactly like the ATS rewire, cutting the orange/blue wire and running another wire to apps blue wire and tapped in there without cutting.  Previous owner had cut the black with yellow wire and run both cut ends back to the battery, like the suncoast version of the fix.  Should operate the same as what ATS does as both wires reconnect at the battery.

 

I appreciate the help and brainpower guys.

Edited July 3, 201510 yr by Nates1999

WAIT!!! Just noticed I tapped the wrong blue wire.  Crossing Fingers

according to drawing on ATS site, your supposed to only tap into the org/blu an blk/tn wires not cutting into but stripping bk enough to sodier wire to oem wire

I did it exactly like the ATS rewire, cutting the orange/blue wire and running another wire to apps blue wire and tapped in there without cutting.  Previous owner had cut the black with yellow wire and run both cut ends back to the battery, like the suncoast version of the fix. 

I appreciate the help and brainpower guys.

I did it exactly like the ATS rewire, cutting the orange/blue wire and running another wire to apps blue wire and tapped in there without cutting. 

 

 

  Should operate the same as what ATS does as both wires reconnect at the battery.

 

I appreciate the help and brainpower guys.

Edited July 3, 201510 yr by rburks

After tpping the correct wire all seems to be working well. Thanks all. Sorry for the chicken little moment.

KOOL   GLAD YOUR UP AND READY FOR YOUR TRIP, HAVE A SAFE TRIP

When you return you better look into resolving it correctly this still only a band-aid fix to the bigger problem.