Heres a little background info...
I have a 99 civic ex 4dr
I was driving to work and suddenly my CEL came on. it was the oxygen sensor that had high voltage(scanned it with a scanner). i ordered a denso universal sensor from sparkplugs.com. I tested it for high voltage and it did. after the car was fully warm, it was idling and it jsut hung around .610 volts. i decided that was defective so i got another one in the mail today, does the same thing and the CEL comes on even after reseting it many times. after i reset it, it takes about 5 minutes for it to throw the code when i start the car up and start driving. Could this be caused by the contacts on the harness being corroded?


First: Did i wire the sensors up right? I have(on the factory harnes part) the 2 black wires for the heater and the green(signal) and the white(signal ground). I soldered the blue wire on the sensor to the green, the white to white and the 2 blacks to eachother. Is that how you are supposed to wire them up?

Second: Are my test results normal?
I take the posative end on my multimeter and put it on the blue(signal) wire while hooked up to the factory harness and the negative to the white wire. when i turn the key to "on" it reads ".035 volts". when i start the engine, it goes down to zero and then starts to come back up slowly. when the car is fully warm the reading is .610 volts and hangs around there. i know its supposed to jump up and down; it kinda goes to random numbers for a split second(only sometimes when i rev it) when i rev it kinda high but then it quickly jumps up to .6 volts or around that (+ or - .01volts). when i shut the engine off the voltage drops slowly till it gets to zero.

IF anyone can help out at all, i would really appreciate it. its getting really frustrating and i know alot of other people have this problem also


Modified by imadigitalgod at 9:35 PM 2/28/2005


Modified by imadigitalgod at 10:15 PM 2/28/2005

 

Not knowing the wire colors for that particular sensor, you can try this at least: Since you're assuming the two black wires on the Denso sensor are for the heater element (because on the Honda side, they ARE the heater wires), then simply disconnect the sensor from the harness and measure the resistance across those two black wires. If the resistance does not come out between 15-40 ohms, you at least know that you have wired it up wrong (or that you have a bunk sensor).

What code are you getting: 1, 41??

 

yeah i allready did tht part. also the instructions said the blue and white was the signal and ground. i keep getting the code 1. im going to turn on the car to0day with the sensor off and measure what voltage is comming out of the harness(the one conncted to the ecu) so see if the sensor side of the harness is bad and is corroded or something. maybe just the signal wire is disconnected or corroded on the harness? idk if anyone else has any info to help me(and a ton of other ppl that have this problem) it would be very helpful.

 

There are two wires - one for the signal, one for the ground. Measure the resistance from one end of the wire to its terminating end in the ECU connector - this would let you know if you have anything corroded or disconnected.

I don't think measuring the voltage that 'may' come out of the ECU without the O2 plugged in will account for much. Do you know what good and bad numbers would be? I don't and the Helms doesn't either.

Also - which wire on that O2 is the signal wire - Blue or White? That wire needs to go to the white wire on the main harness. Have you tried reversing the Blue and White wires yet (or do you know for sure they are correct)?

 

right after i posted this i went out to the car and measured the voltage and i was getting a negative reading sometimes when i reved it and that didnt look right so i looked at the instructions and then looked in the helms and the instructions were wrong, it showed the green wire as the signal wire so i switched the 2 and it worked finally...im glad it wasnt anything else that was wrong with it. The stupud sensor has the white wire as the ground wire and the blue as the signal...opposite from the factory harness that has the white as the signal and the green ad the ground.

 

Glad to see things worked out for you - sucks the instructions were wrong for your replacement O2 though.