You need to replace the ASD relay with a new one first. And check the fuses again.

 

replaced with a new one, just cranks and cranks.....anyway to bypass this...or am i looking at the pcm?

 

I don't know of a way to bypass it. But I do know that my manual says that code 12 is (Memory Standby Power Lost) ! Not, "direct battey input to pcm disconnected withn last 5 key strokes". And being some what of a regular home computer guru, that means the battery on the motherboard is dead and won't save the bios settings. So unlees you have a bad fuse or relay , I would say yes that the PCM is at fault. BTW! you have checked to see if you have fuel pressure correct?

 

yes have fuel pressure.....no spark at all....got code 12 info from this site.....

"Direct battery input to PCM was disconnected within last 50 key-on cycles"

Well guess tomorrow I order a PCM when I get to work, just hope that fixes it, dang replaced

coil, cap, rotor, stator, plugs, wires, iac, new relay, fuel filter.....ran good for 10 minutes this morning then right back to just cranking and cranking

 

does new PCM need to be flashed, or just hooked up and ran?

 

I'm looking at a haynes manual and code 12 is what I said previously. I know haynes is not the best thats out there but it says what it says. And I know comparing a home pc to a car pc could be completely off base and you realize that is just a theory. I hate to have you go buy something that it doesn't need. If you get one from dealer I would no on the flash, but maybe you can get one from a used auto parts yard cheaper and it wouldn't hurt the wallet as bad. At least you'll have an extra for diagnostic purposes.

As long as you have checked all fuses,relays, wires including grounds to engine and chassis, and all the electrical plugs and connections I'd say what else could it be.

And one last thing, HAve you checked the map sensor? It is cheaper to try than repalcing the pcm.


BTW, I have an 88 Dakota Express.

 

Just wondering! Have you disconnected the plugs from the pcm at any point with the battery not disconnected?

 

Have not disconnected the PCM at all, Only good thing, I get all parts at cost, since I am in the industry, but this trck is drivingme bonkers, have used trouble trees etc, everything led to the coil, or stator...so replaced eveything, and now seems like PCM....Goi to check MAP now..

and I appreciated all the help and feed back

 

Code 12 does not mean the computer needs to be replaced. It seems like everytime I check the codes on my truck I get this code, even when it seems I run the truck for more than a month without disconnecting the battery (which would have been far more than 50 good trips) It does mean the PCM isn't getting battery voltage once the key is set to "off" but is nothing to worry about really.

From the reading I have done, the only thing you need to worry about is disconnecting the PCM within 5-10 seconds of shutting the truck off. If you disconnect a connector from the PCM and you haven't allowed 5-10 seconds after you removed the key from the ignition, you could cause irreversable damage to the PCM. Otherwise, you can disconnect a connector from the PCM with the battery still connected (I've done it), but I wouldn't suggest it.

I don't think it's the PCM, I believeyour problem lies with either a part or wiring. The PCM's are typically very reliable, and almost everyone that does replace it, it doesn't fix the problem. Another reason I don't think it's the PCM is because your auto shutdown relay (which is switched by the PCM) is working. As I said,the ASD relay provides power to the fuel pump, injectors, and ignition coil (amoung other things). I mean, just because the ASD is being switched on by the PCM doesn't mean it doesn't have another internal fault.

And, finally, these older computers should be "plug 'n play."

 

Will it start if you hold the pedal to the floor?