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oldgeezer 10-08-2011 07:44 PM

Proper reset procedure for PCM?
Beyond resetting codes with an ODBII scanner, what is recommended alternative method for resetting the PCM? Some say, just disconnect neg. ground and others say to disconnect the Pos. What are differences in mentioned procedures, and which is preferred method? How long to "remember the factory" base settings based on miles driven or ??? Thanks for any inputs. Motor in question is 5.7L 2005 WK. Thanks for any/all help. :thumbsup:

robpp 10-08-2011 07:57 PM

Re: Proper reset procedure for PCM?
FIRST disconnect negative.

then you still need to DISCHARGE things. can be done a few ways:

diconnect positive and touch it to ground;
disconnect positive and touch it to negative cable;
turn on lights for 30 seconds;
step on brake for 30 seconds;

prolly more ways to discharge things but those are ones I know;

that will have no affect on codes per se; they are stored until cleared with the scanner or some have conditional resettes if the issue goes away.

also without a STARSCAN or other CAN BUS capable reader you are only getting the codes stored in the PCM; you are not SEEING or CLEARING any module codes.
EX: P0700 code is common one from PCM but all it tells you is there are MORE CODES BURIED in the TransmissionControlModule which is NOT ACCESSIBLE with your code reader.

in english: the trans module has a problem it throws a code. a generic code is sent to the PCM to turn on the CEL. you see that code that is sent to the PCM. but you cannot see the TCM code which will give you the specific codfe details.


oldgeezer 10-08-2011 08:17 PM

Re: Proper reset procedure for PCM?
Thank your for the detail. Much appreciated. What scanner do you recommend for a person who is cash strapped, but is looking for ROI(Return on Investment)? Thanks for your/others help and direction.

2005JGC 10-08-2011 11:58 PM

Re: Proper reset procedure for PCM?
buy an older vehicle ;)

Im not trying to be overly smart assie (only a little), but cars are getting more and more computer controlled and the only thing that is federally mandated to be easily accessable using SAE J1850 is emissions data (J1850 is reguarding the data link connector with specific pin out for emissions information accessability). I have not personally dealt with an aftermarket scantool that can read other chrysler modules as I deal with the stuff made for the purpose of talking to just chryslers, but if there is one it will likely be in the range of 2500-10,000 dollars dependant on what brand you go with and how many extras you get with it (your typical higher end scanner)... the harbor freight scanner wont get you there ;)

cliffs notes: you likely wont get a return on investment on any legit scanner to do what your looking for.... not that it takes a rocket scientist, but its also not just about having something that will talk, you also have to have a pretty good idea what your looking at and what to do with it, and without that you have an expensive machine that tells you words on a screen ;)

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