I have encounter a problem with my CEL on a 99 em1. last year around this time when i purchased the car, after a few weeks of driving it, CEL came on. So probably like any other honda tech forum members, i checked for the code. it gave me 61 which was primary oxygen sensor. i brought it to my mechanic and changed it. Thought it was all over, but the light popped up again after a week with the same code. They thought it was a faulty sensor so they replaced it with no charge. this time i really thought i got it over with. After driving for a few months, it once again came up same code. I have lost hope and wanting some help to get an idea what is wrong. Thanks

 

run a chipped ecu and have it disabled and swap ecus when you have to go through emissions and put a new sensor back in. some how the o2sensor is getting contaminated and blowing it. they are very fragile

 

how much would a chipped ecu cost? Is there any particular reason that the o2sensor will get contaminated so easily? and thanks for the info. +1

 

check the wires their might be a short

 

Check to see what the wave form of the sensor is ,also get a P code for it.. so use a OBD II scan tool and get the specific code. Sometimes there is circuit or performance codes they put as 71.

 

so lately the CEL didnt prop back on. Was just worrying if it will the future.