Ok, so today I rebuilt my ALDL to RS-232 cable. Even though my ALDL is now well useless. However, I ran the serial data line all the way back to where I have the PC permenantly mounted in the car, as well as the field service line (D20 white and black). Turned it on, tested the cable, cable works fine, turn the key to run to fire up the PCM. Read PCM! Nope, says incorrect response, I assume this means it wants to be in field service mode, so I hit the field service line to ground....no effect....then I remember something about putting the field service line to a 10K resistor, then to ground....I start hearing the wirring of my fuel pump! I go check the pressure, sure enough the pump is running. I didn't think the pump should be running in field service mode.....so any ideas whats going on? Does the PCM somehow think the motor is running, and wtf would ever give it that idea, I know the opti's not turning! Should I just let the pump run even though the injectors arent firing? I'm really at a loss hereThanks
Corry

 

ttt

 

What's field service mode? What did you connect to if you don't have an ALDL port? I just use a laptop and cable. The pump doesn't usually run during reprogramming.

 

Ok, once again:
I ran the serial data line (D30 if memory serves, and is tan) from the PCM itself, to the back of my car, and directly into the interface. I also rand the field service line from the PCM (D20 and is white and black) from the PCM itself to the place where the interface is. The interface is in the back of the car where I have permenently mounted a PIII800MHz ATX computer (Not a laptop).
I believe that the PCM has to be told to go into field service mode, which should use the field service line from the pcm to put it in that mode. When I just ground the wire, nothing special happens, when I ground it through a 10K resistor the fuel pump engages. So I think I am doing something wrong as far as getting the PCM into field service mode. In both cases I had the key in, and engine off. The engine cannot start since VATS is still enabled on the PCM, which is why I am trying to reprogram it.

 

Why in the world would someone not spend the $65 and get a good, proven cable instead of messing around and wasting time with all this stuff?

My guess is that you're probably working with the wrong wires, and this might not end up good...

Either way, try reaching Andrew Mattei at amattei@mindspring.com and ask him for an opinion. I'm sure he'll be more than happy to help.

 

Field Service Mode engages many solenoids for testing purposes. I have never paid attention whether it operates the fuel pump relay, but it might.

 

I think the problem here is that most of us aren't sure what you are trying to achieve. Why do you have a (not a laptop) PC in the trunk? Why are you trying to connect it to the ALDL? Why do you want to put it in field service mode? What software are you running on your PC?

Maybe all this is obvious to others, but I haven't the slightest idea what you are trying to accomplish, so its hard to help.