OK -- From your description, I would hazard this comment ... since you found no shorts to ground in your meter test of the wiring, and the fuses did not blow when the connectors were unplugged, the PCM is at fault. You kinda proved that by plugging the PCM back into the system, and blew fuses again.

Then, you put in a larger fuse and tried it, and blew that one too. (something that I would not have tried, but it's your car, your decision...)

Now, the fuses no longer blow out, but the engine still will not start. I'm of the opinion that the PCM needs to be replaced, but I'll listen to other thoughts/comments ....

 

I like OldNuc -- he's a knowledgeable straight shooter.

Is there any corrosion on the pcm connectors or plugs that might be causing an intermittent short to another terminal or an intermittent connection? I'd think you'd have noticed while tracing but feel compelled to ask.

Usually when solid state circuits fry internally they stay that way --- if the internals for the PCM B circuit fried to ground, I'd expect them to stay that way.

I also wouldn't expect another batt feed to the PCM to fry out in the midst of testing

nor would I expect both circuits to suddenly be OK(not frying fuses) -- unless the pcm internals at the terminals both fried so extensively they are now both open circuit.

Are you still getting 12V at the pcm harnesses for PCM A and PCM B?

You might want to poke around at some sensors with key on (like the coolant temp sensor) to see if they're getting any juice, and also see if the diag port is functional--- if your PCM is toasted I'd expect a whole lot to be not working if you've killed all power to your PCM

 

what do you think about it possibly being the crank positioning sensor?

 

no corrosion anywhere at uhjb.

and yeah, i thought it was odd to have pcm 1 fuse to fry as well.

i will check today to see if i still have 12v to the pcm.

.......to be continued.......

 

Defective CPS will indeed inhibit spark if faulty, but if pcm is hosed, any CPS signal (good or bad) would never get interpreted correctly.

Or are you asking could a shorted CPS cause all of this?
I don't really don't think so but it's easy enough to throw your ohmmeter across to calm your mind....

 

plugged in a cheap actron scanner and a super deluxe high zoot zillion dollar napa genesis scanner and both say no communication with car. the mechanic who owns these scanners says its probably the pcm fryed......lkq will sell me one for $100 with a 6 month warranty. hmm......

 

There are some for sale here:

http://www.ebay.com/sch/i.html?_saca...999+Saturn+pcm

the used ones are under $100 and the remans closer to $200.
Personally I prefer the OEM used ones pulled from wrecks/junkers cause you know at one time it actually was functional in an S car.
Need to be sure the part numbers match.
Also I believe it will need to be reprogrammed at a GM dealership with the appropriate programming tool.

I'd actually find the part number off the existing PCM, then call a GM dealer (preferably one that used to service Saturns) and ask them to look up acceptable part numbers that can serve as replacements.

 

open door, dome light goes on. i put key in, it chimes. turn ignition on, lights on dash go on. stereo works, hvac fan turns on. everything works like it should. i will check power and ground to obd II port next per your instructions....

 

I believe all of the circuits you mentioned (except the ODBII) are fused separately and do not rely on the PCM for power -- so it is should not be unexpected that all that stuff works but the diag port does not.....

 

body fuse is good. checked power at obd port. orange is 12v, i am almost ready to order another pcm on ebay....50 bucks....