I have a question about my 03 civic hopefully someone can help.. the bottom bolt on the alternator broke on my way to work the other day. It still ran but had no power until i could get pulled over. I fixed bolt an tighten alternator back up. Car is making a clicking noise from a relay under glove box sometimes. Car starts, idles an runs but has no power, no gauges work on dash. I checked an cleaned all the grounds that i could, i unhooked alternator an started it just off the battery to see if the alternator was crap an it ran the same. YouTube an Google are sending me to the ecm. When i scan it, it says it cant connect anyway im trying to figure out for sure if the ecm is smoked before finding one. I found one for a little over 100 bucks without the ignition but it says "warning this ecm has an immobilizer an may not be programmed at the dealer". This is the only one i could find so far with same part number. Should i find one with the ignition an change it to or do u think honda would be able to program it? An does the replacement ecm have to be out of a manual since mine is a 5 speed? An what years would fit my 03?

 

To test the alternator use a multi meter to check the voltage . I know people un hook the alternator or run it without but with the electronics I don't think it's a good idea . The ECM gets a signal from a transponder in the ignition that reads the chip in the key to allow the car to run far as I know , it's even more complicated than that . Shop for a new ECM that would be compatible with your car , I think not being able to connect with a scan tool is an indication of a bad ecm . The clicking sound may be a separate issue , other things can go wrong by pure coincidence .