So I'm pretty sure my PCM is a goner. I was in the middle of a tune on Tunercat when an error security message popped up and terminated the tune. So I rebooted the computer and the PCM by removing the fuse and once again about halfway through the read an error pops up saying, unable to communicate with PCM. I then tried my datamaster and freescan, at first neither worked, eventually during a force interact with Freescan it communicated. Unfortunately the car will not start and I can not reprogram it...any ideas?? O yea and its a USB to serial A&K cable to OBDI

 

Here " http://www.madtuner.com/index.php?pa...mart&Itemid=26 " --or-- a junk yard replacement for $50-75.00. If you are into electronics there also some DIY procedures on the internet that require removing and soldering new chips into the PCM. I was seriously thinking of picking up a spare PCM in case this happens to me. I use straight USB cable, quite a few loads and so far no problems..knock on wood.

 

Contact Andrew at AKM Cables, he will replace the damaged chips for a very resonable price.

 

Chevyguy358:

Sounds as though the PCM is still alive (barely!) since you were able to establish some communication response. Is the car battery fully charged? Is the laptop battery fully charged? Check the TunerCAT calibration file that you're trying to load into the PCM. Is it 128kb in size? Check it with windows scanfile for any internal file checksum errors. Open it and review the values for the switches, constants and tables to be sure they are what you want and look reasonable. Try to read what's in the PCM with Tunercat ... from your description the PCM still responds to the ALDL port but may have corrupt or missing values in it's memory. As I recall, when a PCM read is successful, TunerCAT then resets the PCM as though the key was just turned on. Whether or not that works, and if your calibration file looks valid try to load it again. As long as TunerCAT can talk to the PCM there a chance you'll be able to load the file and recover. If none of this works then you might consider trying to load the last tune that you read from the PCM from when the engine was still able to run. If that load is successful, and the car starts, then you can always change the tune to what you want. Wishing you good luck!

 

Unclear on whether the original operation that failed was a read or a write? If a read, then it's extremely unlikely that the PCM is hosed.

If a write, what does "middle of" mean. Does it mean the progress bar was about 50% complete?

There is a pretty common "security" error that pops up in tunercat at the beginning of a write attempt, and if that's what you mean, then this is also not a PCM-frying event.


Yep. The fact that you can get partway through a read suggests that the PCM is not hosed.



I would not try any further writing operations until you can successfully read the PCM. Partial reads almost always indicate wiring/adapter/voltage problems.

Regardless, pick up a used PCM from the forsale section on this forum. You'll need it eventually if not now.

 

Yea it was literally half way through the tune when it had an issue, i was uploading a revised tune to it. The file is infact 128kb and everything on it looks good, the only revision was slight individual cylinder fuel trim adjustments at idle. I have yet to read the pcm as the same error or other errors occur terminating communication. I am goin to reinstall the drive for the cable, charge the battery for the car and of course pull the pcm fuse in the mean time. when you guys say it could be "almost gone" do you mean that has or has not likely sustained some sort of physical damage? Should it be replaced regardless. If so, I went ahead and placed an order at orilleys for one refurbished with LIFETIME warranty and they even price match AZ for $104! It should be in tomorrow morning. If i don't figure this out by then I will just install the new one and see what happens. thanks alot guys!

 

It's not physical damage.

I think what he meant by "almost gone" was that it appears that the tune portion of the code is messed up but the communications portion is working. It's when the communications portion is messed up that it becomes a brick.

After you get the new PCM, if you can read/write it without problems, then try flashing a known-good bin (like, the one you download from the new PCM) onto the old PCM.

Try reading the new PCM like 5 times before you try writing it. If you can read 5 times without errors you probably don't have wiring/interface problems.

 

i will try that. Thanks again!