No “service eng. soon” or “coolant” lights and car won't start.

Today when I tried to turn the key to “on” position no “service eng. soon” or “coolant” lights came on and of course the car won't start but do cranks, Tried with jumper cables with other car but nothing last day it worked was Sunday and worked fine. I have an extra ecm that I remove from another GP at the junkyard like 2 months ago but when I put it in the “service eng. Soon light” came on and it gave me the 34 and 12 codes so I put the old back and the light turned off but tried that today and no response no lights nothing like no response from the ECM jus the breaks and seatbealt lights came on, Anyone can give any advice (again) Thanks.

Did the car start when the ECM was changed? It is possible that the codes were stored in the ECM that you put in the car and it has no relationship to your car. You can clear them if the car runs and see if the light comes back on.

Did you swap the PROM chip from your original ECM into the Junk yard one? The PROM is calibrated to your car, the ECM can fit multiple vehicles with different engines. If you didn't swap the PROM, the new ECM may not work in your car. A code 34 is MAF or MAP sensor (depending on year and engine), which if bad, can cause a no start issue.

Sorry for my ignorance I changed the blue thing that's inside the black box like 1 month and gave me the that code and inmediadtly put the old one back and no light came on but I did it yesterday as of last resort but won't start with neither one no lights came on so I can't use the code reader because I need the "no service eng soon" light to read the codes.

2.8 Fi
36,000

check the ECM fuse.

Thank's richtazz (http://www.automotiveforums.com/vbulletin/member.php?u=221877) and GTP Dad (http://www.automotiveforums.com/vbulletin/member.php?u=181570) I think I found the problem just in case I replaced all the fuses from the glove box even though none were burned with some of the 99 cent's store and the door lock's and the ecm got burned almost inmeadtly so I went to pepboys to buy some with more quality and now appears to be ok but the wird thing is the first fuse is not burned that's why didn't though of it.