1999 4.3 write failure
I have a 99 4.3 in a jeep and its all wired and I can read from the pcm but it wont let me write. Im trying to disable vats. Is there something special I have to do to write to the pcm? It timeouts at Erasing PCM and fails everytime. Ive never had this issue with any other motor but this is the first 4.3. I noticed there are two Serial data lines in the black connector, one being pin 11 and the other 14 I believe. I have tried both seperate and both together. Someone please help. Also can I use a vats bypass box on this computer like on f-body computers or not? If so which wire do I need to attach it to?
Thanks.
The ALDL I have the 2 grounds attached to the neg. side of the bat. the orange to the positive side and the purple to the data wire from the pcm. There is a tan wire on the ALDL also but I didnt hook that up to anything. Like I said there are 2 data wires and no matter how I hook those up I can read the pcm but can't write to it.
Got a NEW computer from the same year/model vehicle to try
Got a NEW laptop with all the updated drivers and software from HPTuners
Got a NEW VCM Suite from HPTuners (friend bought the setup aswell)
Still having the same problem we can read the tune from the computer but cant write to it. Get the same error about a timeout on erasing vcm. Any help please.. Does somebody have a wiring schematic to a 1999-2000 s10 with a pcm with the 4 plugs so that I can compare it with the ones I have just to 100th check the wiring again..I can't figure this out and its driving me CRAZY
Last edited by 85irocinjected; Feb 7, 2009 at 09:15 PM.



