Engine/Transmission (1998.5 - 2002) Dealer says he can't flash my PCM

[cosborne]

So I've been going through the lock/unlock problems and gear hunting issues with my truck. I have read all I can about what causes this and have even ran a wire from the output on the APPS straight to the PCM, bypassing the ECM. I have checked most of my grounds that I can see or find and cleaned them. Each of my "fixes" have lasted about a day or two, then the truck starts hunting again. Last night I took it to the dealer to try and have the TSB 18-02-99 reflash done. He hooked up his scanner, looked up the part number to reference my truck, checked for codes (none were present), went to the main computer and downloaded the update, came back to my truck and proceeded to flash it. After about 15 min and 4 or 5 trys, he tells me that he can't flash my PCM... it just won't communicate with his update.



He said he has only had this happen once in 10 years, and that he suggests I replace the PCM!!! All I want is my transmission to stop hunting and I am fairly certain that its not the trannys fault.



Any thoughts? My next option is the Happi box ($100) or DTT noise filter ($50), or a new APPS ($470 from the dealer)... . and is it bad that my PCM can't be reflashed???



Thanks in advance..... :{

 

[Dkuhlman]

Just out of curiosity, have you tried disconnecting your EZ and test driving? I disconnected mine and it helped the shifting a lot, so much so, I'm leaving it off for now.

 

[John - K5AWO]

It sounds to me like you need to get the noise filter from DTT and install it on your transmission. Noise from system components can cause transmission shift hunting.

 

[jpmutt]

I have had problems in the past trying to flash pcm's ecm's etc. Sometimes if the cable is damaged, not getting a good connection, or if the flash was not properly downloaded into the DRB you will have problems. I am very familiar with the flash and the TSB you are talking about and feel that this is probably your problem. I would recommend taking it back to the dealer and have them try using a different DRB or just trying it again. It may help to disconnect the battery to clear the pcm before trying to reflash it.

 

[cosborne]

Thanks for the suggestions guys!



jpmutt- I am headed back to the dealer tonight (he was going to get me a price to replace the PCM)... but I will ask him to retry the flash... ... I really want the Flash !!!!



Thanks again!

 

[jpmutt]

Thats what i would recommend. At least it might save you about $1000 bucks. Good luck!

 

[cosborne]

So after a trip to the dealer last night and three trys with different DRBIII's and even a hookup to their "main" computer they still can't get my PCM to take the re-flash. :{ This guys is a good guy friend of a friend and offered to replace the PCM at his cost for the part ($250) which I think is a great deal, but now for the last 2 days the truck has shifted just fine. All I have done is lossen and tighten the easist grounds that I could see and maybe jiggle some wires around.



So my question is should I replace the PCM? Might there be other things wrong with it that I don't know? The tech says he can read what he needs to just fine, but that he can't write to it. If I replace it will a new one be any different in other ways? I ask this after reading that some guys trucks aren't quite the same after getting re-flashed in some instances. I'd hate to spend the money and be taking a step backwards.....



Thanks again for the help!

 

[jpmutt]

Well, sorry to hear that. If it's shifting ok now just drive it till it breaks, then go from there. Have you checked the adjustment on the kickdown cable yet, if it's to tight it may be messing with you.

 

[cosborne]

Is that located in the same place as the APPS sensor on that same bracket? I know the speed control cable and throttle cable are there... what should I look for ?



Thanks... .

 

[msmithac]

I had this happen a few years ago to my 98. 5 auto dually. I took it to the dealer and the tech drove the truck, verified the torgue locking and unlocking above 45... . They could not find any one thing to be wrong DRB said everything was doing it thing as it should... . they replaced the PCM and that fixed everything... ... 4 years and 125k later orginal trans and still shifting fine... ... $850 +/- lighter though :--)