Using tunercats, I go to "Tools>Read PCM" Do Not Distrub dialog box appers, blue status bar fills 3/4 way, fans on the car come on, then shut down, the tunercats software comes up with a box saying "Invalid Response from PCM"

Let me tell you what I've done to make sure it wasnt the cable, laptop, or pcm.

Using Hyperterminal there's a data pattern streaming w/key on, motor off.

COM1 set @ 9600bps

 

Disable infrared port if you have one. And disable any other COM port but COM1. IF that doesnt work then you are basically out of luck. I have learned the hard way that some computers just dont cut it. So far IBM has been the only brand I can count on... so far.

 

This is killing me, alright, So I use to be able to run datamaster no problem. Now while in monitor mode, engine off, key on. I get no errors, but of course that's pointless.

Start the motor, all perimeters are jumping through the roof. Speed being the best one, showing im doing 120+ sometimes while just sitting there. I keep getting a PCM lost error, then it comes back. I'm guessing I've got a bad ground somewhere, and/or the link between the pcm and the ALDL connector is loose/sliced, frayed.

Last year a friend of mine was able to read and reprogram the PCM. Since then, I've done the passanger side !wire mod. And I'm sure I screwed something up. I'll start there.

 

Make sure your battery is good. That was killing me. You can hook up a set of jumper cables to another vehicle while that vehicle is running and see if that makes a difference. If not, then you've ruled out the battery aspect of things.

Ken R.

 

I've put a battery charger on. (2amp, regular cycle) for my optima redtop. With no success.

I've been running for quite some time w/o the ICM to Chassis ground strap, and figured that would be a good cause. So I reconnected it, motor idle's a little smoother now, but TC still comes back with "Invalid Response from PCM"

-Bryan

*edit*
Also while scanning with datamaster. When the key is in the on position, and the motor is off, I get a flawless stream of data. However when I start the motor. I get "PCM Lost" flashing on the small window status bar. It goes back and forth from PCM lost to Monitoring... while connected, ALL perimeters are jumping across the board. For example my Speed is showing up to 128mph sometimes, while I'm just sitting there.

 

It sounds like the cable might be bad. After rereading your posts I noticed you seem to have the same problem as a friend of mine. He gets crazy readings running datamaster too and we have tried 2 laptops as well as 2 cables and no change has been observed. For the most part the data is clear and reasonable but every once in a while youll see something spike out of control... we never have figured out the cause either.

 

I have the same problem (kind of at least).

For me Datamaster works fine, but I get the Invalid response... error message when I try to read the PCM with Tunercat (2.08).

The funny thing is that I used to be able to read and program my PCM with Tunercat with the same computer and cable (about 1 year ago).

When I tried today I had no luck with Tunercat (Datamaster still works fine).

I have completley reinstalled my laptop since last year (now running XP SP2 instead of XP SP1), I wonder if this (SP2) could have anything to do with it.

Is there any (free) DOS program that can be used to Read and Write the PCM instead?

 

There is a DOS program but I never could get it to work with my laptop. BTW I am running XP with SP2. Worked on my laptop and desktop.