alright guys,
quick question,

i have a 2003 impreza wrx type uk blob eye, im having issues with the cel because of the o2 sensor,

to reset the ecu i was told to dis-con the battery, some people say leave it for 10 secs and some say half hour and some say a few hours?

wats the best way to re-set the ecu, and will that clear the o2 code and stop the cel light coming on on ignition and start?/???

cheers guys

cj

 

Although I've got a classic, I was told the best way to re-set the ecu is disconnect the battery overnight. The ecu has an inbuilt battery to log fault codes and when left overnight the battery runs down and the ecu is re-set. Don't know if the fault code remains logged on the ecu though, but it worked on my classic once I had found the fault.

Hope this helps

 

The fault can only be cleared fully via a diagnostic tool that plugs into the OBD port below the steering wheel. Some O2 errors go away after the car has been started and turned off 5 or 10 time ( I cant remember) and the light should go out. Ultimately you need to sort out the sensor to solve this problem.

 

ye the sensor is workin fine, but im running a de-cat so the emissions are flowing past the sensor too fast and making the cel light come on, ive seen a few fixes that ill try like a o2 simulator, or the plug anti fouler, which just moves the sensor back from the pipe a bit mre lol

but to save me paying every time if the light comes on if the ideas dont work lol, btw is my car a obd2??

 

As you have decatted it the car will need remapping.
When its getting mapped the Mapper can map out the CEL light so it won't come on at all.

 

quicksilver just to add to your comment
its got nothing to do with the gas flowing past your sensor too fast

the ecu expects each sensor to read differently when the catalytic converter is in place - ie then the cat is working
when decatted both sensors read the same and the ecu tells you via the cel that the cat is no longer functional

either remap to switch the code off or increase the "tolerance" in the ecu to triggering the cat not working code

the plug anti fouler you describe is probably the best
by moving the sensor away slightly it will read gas of a different temparature and hence composition and then the ecu will believe the cat is still there and workin

 

Really needs a full remap but at the very least it needs the CEL switching off in the map to stop you getting that error.

 

ok thanks guys, just £500 for a re map, just for a de-cat seems expensive

 

do what i suggest with the anti fouler or go to www.tactrix.com
buy the appropriate cable
go to openecu.org
download the latest version
plug into your car
download your ecus map image
disable and prevent the ecu throwing a cel for those cat codes
upload map image to ecu
job done

while you in there you may as well lift your boost cut / speed limiter and do a few other simple things

way less than 500 gbp

 

Could I do this type of thing on a Classic STI?

 

hhhmmmm sounds like a plan, although ive been offered a remap for £350.00 decitions decitions lol