Any of you Tunercat users out there ever experience the "Incorrect message sent" errors during reading or programming? TunerCat help says it's a connection or cable problem, but I've already read the PCM once and made a copy of my program and I can run Freescan with no problems, so I don't think it's a cable or connection problem. This error came up all of a sudden and it happened tonight while I was trying to program, but unfortunatly happened right after it established communications with the PCM and erased the flash before programming. So now, I think my PCM is a gonner cause there is not nothing programmed in it. Hopefully, I can get it fixed, but in the mean time, wondering what can be causing this problem. I was running it straight through DOS at the time (not a DOS window) I first started getting errors, then downloaded TC's new version which can now read and program straight through the wintuner and you don't have to go to DOS. Thats when the PCM wipe happened. But it still gave me the Incorrect message sent error weather using the DOS based version, or the windows based new version. Any help would be appreciated. Thanks.
Ken R 95Z

 

I had the same problem the other day when I first tried to read my PCM. I was using a dos and not the dos-based window too, like you said. It happened about 50% way through, then a second time it happened at closer to 10% and this is what I came up with:

Low battery voltage. TunerCat checks the voltage before it starts to read, and mine was within range. However after a few minutes of having both radiator fans on, the battery voltage dropped too low, and the PCM shut down, causing the laptop to lose communications with the PCM. What I did... I hooked up a jumper cable to my brothers car, his car off, and between both batteries there was enough power to keep the fans going until the pcm read program finished. It was a PITA... but I guess my car's battery just isn't big enough.

I was afraid to write to the PCM knowing the problems I had reading from it... I hope your PCM isn't ruined but please let us know... does the car run at all now? Good luck...

 

I was also thinking that it was a low voltage issue when I noticed that the green eye in my delco battery wasn't so green anymore. And I was also thinking of trying the jumper cable trick. Unfortunatly, the PCM is dead. It lost communication right after it erased the flash and programming started. So basically, if you lose it after the flash wipe has been done, your screwed! Luckely, the PCM isn't dead. Andrew at AKMcables can actually bring them back to life for a fee. I'll be sending it to him in a few days. I also have a backup PCM and will probably try the jumper cable trick but using the read function first cause I don't think you'll lose anything just reading it since it doesn't erase your flash to program. So you actually got around those errors with the jumper cables? Something to pass along to TunerCat because they don't know what could be causing it. Moral of the story: If you have any doubt that you might get errors or are currently getting errors while trying to read, then don't bother to program till you get the problem worked out. Thanks for the feedback.

Ken R. 95Z

 

i dunno about the low voltage theory...

when i first tried to read/flash my car, it took me a long time to actually get it to work which meant the fans kicked on/off several times. the laptop i was using was kinda tempramental so it took me a while to get the process done completely. well when i went to start up my car...it was dead. my battery was so drained that i couldnt kick the starter over the flash went find and my battery was LOW.

i suggest just going with what works. just boot it up in DOS and dont worry about it screwing you again.

 

You say just boot it up in DOS and don't worry about it again... but I was booting it up in DOS to begin with! I don't understand why the fans need to be on in order to program the silly PCM anyway I wonder what would happen if I were to disconnect the fans and then try it... maybe it's worth it to try and read the PCM w/ them disconnected?

And roguedriver... why wouldn't you just be able to retry programming the PCM, if you could get TunerCat to finally program it right why wouldn't that work? This is sure sounding risky to me...

 

Turbo_Z, I couldn't get it to work in DOS mode either. So either way, it kept losing communications for some reason. Still want to go with the voltage theory. When I first got Tunercat, I did a read and copied my file with no problem, but when I went back to program a day later or read, no go. So i'll try doing reads when I get my PCM back. If I consistantly get errors reading, I will try and hook up jumper cables to another vehicle. If the errors go away immediatly, i'll know it's some kind of voltage issue. I'll post my results. And BlackCamaro. As for trying to reprogram the PCM, it's too late for that. Mine errored out after already erasing the current flash meaning that if I tried to go and reprogram it, there would be nothing to see to initally start programming. I believe it has to see the flash in there first before erasing it and putting your program in. Sent the PCM off to AKMcables today along with my cable to verify it. But it should be working fine since I was able to run Freescan with it. I'll let you guys know. Thanks for the responses.

Ken R. 95Z

 

This is just a question to throw in the air... if you reprogram your PCM, and then disconnect the battery, does the PCM forget your programming and go back to stock? Meaning... in cases where there are errors writing to the PCM can you just reset the computer to stock programming and start over again? Because for roguedriver, how would he be able to use freescan on his car if his PCM is garbage?

 

When you reprogram the computer, the changed program is stored onto your PCM(such as saving something to the hard drive on your desktop/laptop computer). Hence, unhooking the computer will not reset it back to stock. It could be useful in some instances(such as when the laptop locked up while programming and toasted my PCM day before yesterday), but I believe would be more trouble than it's worth if it worked like that.

 

Make sure the connections are GOOD, even off by a little bit can cause 'noise' in the line.

I also like to pull one, or both of the FAN relays, FAN #1/2, which helps battery life, especially for me who would often FLSHREAD before I FLSHPROG to make sure everything was OK.

Even while doing this, I would sit in the car for the 3 minutes or so the process would take, because if you move again, this can cause noise in the line if the cables get disturbed at thier connection point, so I figure on being safe instead of sorry (when your writing at least).

As said in above post, the reprogram of the computer is NOT temporary, it is a FLASH chip not RAM, if it was RAM then every time you removed the battery or removed PCM_BATT fuse you'd lose your tune, when you only lose your learns doing that. The program is BURNED onto the EEPROM, its not temporary. Hypertech internally has enough space for 2 tunes, which is how they do it, but the stock PCM has enough space for one only, wether stock or aftermarket tune or what have you.

 

I've mentioned this to the Tunercat people and not sure anything will ever be done with it now or in the future, but LT1 Edit does turn off the fans, Tunercat doesn't, which is why I pull the 2 relays for the FANs, or even just one of them saves alot of battery. If I'm going to be sitting there reading and writing though then I figure on pulling them both. My FAN #2 never really gets used with the turn on point I have it set at anyway, so I have #2 unplugged permanently, to make yanking #1 the only job before I read/write.

It works just fine without them being on, just make SURE that your program completes before you turn off the cars key breaking the PCM connection, make sure Tunercat reports a reset and/or listen for the fuel pump to kick over. I once turned off my key a tad prematurely, but thankfully it had reached 100%. It had not yet however reset the computer, so the car would not fire, after several tries I was very, very nervous being 160 miles from home. Thankfully yanking the PCM_BATT fuse was all that was needed, but, better to be safe than try to save a measly 5-10 seconds, just wait till it fully resets

 

So by disconnecting the two fans during the process of either reading or writing, won't cause damage to anything and saves battery life? Sounds good to me ... and also, Dr. Mudge, I thought when you turn on the a/c that it also turns on the second fan... might want to leave that relay in during the summer hehe... Have a good one and I feel safe to go writin' away to my PCM now Just gotta be careful not to make those a4 shift points too high hehe...

 

Blackcamaro, I was able to run Freescan when I first started getting errors using the DOS version to read or program. Programming in DOS never got to the "erase flash" point before aborting, so I was still good to go. Then I ran Freescan to see if it was a connection or cable issue, but it always ran fine. It was when I went to use Tuner's new windows based read and program version where I got screwed. The new version is nice though, but what got me was when I went to try the program, it got through the establish ECM communication and reset, but then crapped out after the "erase flash" step instead of before. At that point, it was a done deal. Pulling the fan relays is a good idea though to keep from drawing your electrical system down too low during the program. I'll have to try that one too. But for now, i'm waiting for my poor, decreped PCM to come back from repair.

Ken R. 95Z

 

Well guys, I just took out both fan relays and...

Same problem. The first try it got to a little less than 50%, and gave me the "incorrect message sent" error. Tried it again and it didn't even get to 10%. I'm still thinking it's the battery being drained though, but if not by the fans then I don't know what. Maybe the fuel pump relay? I think in the future I'm gonna upgrade to a yellow top battery to listen to the radio w/o needing the engine running... which will also help this problem. But it's really ticking me off 'cause I won't write to the PCM until I can read with no problems and I can't read it!!!

 

Oh, I dont know about that! I always do this stuff BEFORE messing with the computer. Remember if I'm writing to the PCM I'm sitting on my rear end in the car, not moving, just watching.

As for AC, I dont have any

Something of interest, there was a later version of FLSHPROG not just the Windows version, but due to some small update of the PCM logic or something later on. I dont remember if they called this a 94b or 95b or what, but there was apperantly some small change. I think I recall at least one user of this site reporting needing it, as thats how I heard about it.

Fuel pump relay wont do hardly anything, the FANs however suck BIG power, I can see visibly my battery go down at the end of 3 minutes which is why I removed the relays. Even though it wont KILL your battery, it puts a strain on it and shortens its lifespan by being drained to that point. Make sure your battery is fully charged before doing any writing, by driving around for awhile and looking at the gauge. I belive it takes a drop to 11.9v before you nuke the PCM, and it only takes something like 100-400ms before that happens and its too late. I actually had a scary experience once, where my power inverter (when I was using a 486 laptop with no battery) actually made a reset sound, I thought for that split second I was toast, somehow the programming resumed! After that I went back to using my old inverter which didn't ever do that.

If you read before you write, like I often do, and you leave the relays in you could be asking for trouble, not sure, but my own battery would be drained pretty heavily and that just made me too nervous. Also again make sure your not moving around on the seat, and you have a darn good connection at the OBD port, AND that you have the serial plug in FIRMLY to the back of your laptop, it does not have to be screwed in hard but it should be threaded in so that it doesnt' budge, because if it does that will again cause noise or loss of connection/data and that is no good!

 

Dr. Mudge, you've been a great help so far and I thank everybody a lot . After re-reading my post about the fan relays I realize I made it sound like I wanted to take out the relays WHILE the laptop and PCM were communicating, but I meant if I were to take the relays out before I started the laptop up, if that would mess anything up.

I'll look at tunercat's site now to see about that flash reader and writer update... that would sure be cool as heck if that's the problem. However, I did get it to read once when I hooked the car up to another battery, so I'm just pretty convinced my battery is too small or doesn't have enough CCA or whatever... to keep the PCM going for too long w/o the alternator to charge it up. So who knows... .