ECU memory problems
 

Hey everyone! Long time lurking first time posting!

So I took my Honda Civic from Illinois to Georgia and had to register the vehicle again. When I went to register it, I needed to get the emissions taken care of. Unfortunately I didn't pass emissions because my ECU isn't working properly. Apparently when the car is shut off, the memory gets wiped. I don't even know where to start troubleshooting this thing! I've put alot of time and effort into my car on my own, and I don't want to take it to a mechanic because I like tinkering with cars myself, but I've never had a problem with my ECU. Any ideas on what could be going wrong with it? Thanks!

Re: ECU memory problems
 

If the PCM loses its memory power, the readiness monitors reset to "incomplete" when the key is turned off.
This is usually caused by a blown "back up" fuse.
Engine compartment fuse box.


HtH

Re: ECU memory problems
 

thanks for the quick response! that will be the first thing i check, would there be anything else that could be going wrong in my vehicle that would contribute to this problem? and is there anyway for me to diagnose the ecu to see if that fixes it?

Re: ECU memory problems
 

You would need a scanner (code reader?) that can give monitor readiness data, I believe many generic units will give this info.

Maybe check with Danger Zone, see if their freebie reader will do it.

I would probably take initial readings to see what monitors have not run, then drive the car and watch a few of the monitors change state. Then shut the car off. Turn it back on and see if those states were remembered by the PCM, or forgotten and reset to "incomplete" (or whatever wording the tool uses).

HTH