blackiceboi

So this is my first post any help would be greatly appreciated
I have a 96 honda accord ex 4door 2.2L engine
I have tried multiple times to have my car pass emissions
each time 4 sensors have been found not ready...
EVAP EGR Catalyst O2 Sensor
The mechanics at the emissions place tested my car and found that every time i turn my car off the voltage of the battery gets dropped to 0 and when started up the voltage returns...i need to pass emissions and have driven over 400 miles to get sensors ready...
The concept is that every time i turn my car off it resets my car computers monitors and sensors therefore i cant pass emissions
CAN ANYONE HELP

MAD_MIKE

First off I'll admit I am not familiar with the '96 OBDII system. With that said...
Is there a fuse for the ECM memory? If so could it be blown/missing causing this issue? My crapshot theory is without memory power the ECM, obviously, loses memory and resets when turned back on. Although with OBD II I would think that the system would monitor for such a critical error and set a hard fault code immediatly.
Like an older game/arcade system, it works fine all day long but as soon as its turned off all those high scores are cleared.

GhostAccord

Check the back-up fuse under the hood.

blackiceboi

which fuse would it be?

GhostAccord

If I remember correctly it's labeled Back-Up. It's a 7.5amp fuse.

GhostAccord

Does your radio keep resetting as well?

blackiceboi

no the radio presets stay but i do have the clock resetting issue but i dont think that has to do with why i cant pass emissions

Dannyvho

That makes sense: the ECU memory and the clock share the same fuse. Like Ghostaccord said: replace the 7,5A fuse. Hopefully there's no problem with the electric circuit causing the fuse to blow.

blackiceboi

well the person who had the car before me i guess had cut the radio harness and put in an aftermarket and when i got it back i had to buy a factory harness from ebay and hook the factory radio back up but there are 2 wires that i assume are for the clock that i dont know where to hook up

phootbag

I always wondered why the ECU never had an internal power supply like the SRS unit.

As stated, check the backup fuse.

blackiceboi

checked the fuses everything no fuses are blown no change

GhostAccord

Do you have a multimeter & are you familiar with electrical troubleshooting?

With the car turned off. Measure the voltage @ fuse No.1 (Back-up) You should see battery voltage. Then measure the voltage at the ECU pin C10 (WHT/YEL wire), You should also battery voltage at the ECU. The ECU is located in the passenger footwell under the carpet. If you don't see battery voltage at one of these spots you will know that there is an open/short in that section of the wire.

LRey Baez

I'm having exactly the same problem, did you ever find out what it was that was causing this problem?

MAD_MIKE

Have you checked the 7.5 Fuse? Just because it may look good does not mean it conducts, test it. Have you checked for voltage at those terminals? Have you checked for memory voltage at the ECU connector?

What have you done so far?

holmesnmanny

The car won't start with the 7.5 radio/backup fuse blown.

wolfy47

There is a ECU fuse in the underhood fuse box. Although if it were blown the car would not start at all (Back when I had a 5th gen I would remove the fuse to reset the ECU or to try and prevent the car from being stolen in bad areas).

holmesnmanny

yep i do that as well

LRey Baez

I had originally looked at all fuses and thought that the back up fuse was good. However upon closer inspection, the # 7.5 backup fuse was blown even though it lot up on one side. I turned my car on and off and the stereo has kept the time , fault codes are fine now, I'm going to run it to give the monitors time to test, then ill smog it today. Thanks for all your help with this tread.

LRey Baez

My car passed smog, thanks for your help.