kenskii

Hi i have a 98 ej6 civic with a d16y8 engine that needed a gearbox change. So i found a used gearbox and swapped it. The gearbox seems fine but since that day the CEL light is on and when i jump the connector it spits out code 20 and 41. The codes are for the ELD and primary oxygen heater sensor. It seems a bit unlikely that these two components would fail at the same time on the day of the gearbox swap. The car also seems to run fine. So has anyone any ideas on where to start looking for things that could cause these CEL codes such as bad earth or broken wires? Any help would be great as im not sure if i should just go ahead and replace these parts. Thanks in advance :D Love the website helped me an awful lot already :D

civic-steve-94

Get a dvom and ohm wires from the ecu to the o2 sensor pigtail. Check for high resistance or open wires. Also for the eld make sure alternator is functioning as it should and you battery is in good shape

kenskii

Thanks for the reply bud Sorry but do you mean get a dvm and take an ohm reading on the wire harness where the primary o2 sensor plugs into it? also battery seems fine 12.8v and i think alternator is ok battery reads 13.2v or 13.3v while running? anything else for the eld? Thanks

civic-steve-94

ok I was assuming that your car was obd1 since your using the flash technique. DVOM (digital volt and ohm meter), and yes from the plug at the ecu that contains the wires for the o2 sensor or sensors to the plug that the sensor plugs into. should be low like .5 ohms. Also when checking to see if the eld is working all loads must be on like head lights on high, radio, a/c if you have it, and I throw a blinker in for good measure.


If you car is OBD2 find a scan tool that has a data display and see what voltages are for the o2 sensors

kenskii

Thanks man i appreciate the advice ill try that and get back to you :D

kenskii

Ok when you say take an ohm reading do you mean put one of the probes into the wiring harness at the o2 sensor and one into the harness at the ecu at the same time to take a reading? do i need extra wire for that or do i have the wrong idea? sorry if thats a stupid question. Also battery voltage at 14.45v at idle and dropped to 14.11v when i turned everything on. radio, heaters full headlights ect. . This sounds ok to me? Battery seems good too 13.2v when car is off Car is obd2a i think i dont have the universal modern D shape connector.

civic-steve-94

you should have the DLC(data link connector) if it is obd2 and the wiring has not been drastically altered, it should be behind the knee bulster above the hood release. Yes you will need some wire take one lead and prob the pin at the o2 sensor, then connect the other lead to a piece of wire and run it to the ecu connector that contains the pins for the o2 sensor and test away. Also your alternator seems to be working well. What ECU are you running?

kenskii

Im running a p73 ecu. Does the working alternator seem to suggest the eld is ok? Is the dlc the 2 pin i used for flash codes or a three pin wire or a different one? i dont have an adaptor wire for the car to read the codes anyways tho

civic-steve-94

The eld is actually another component. But this is still very strange that you don't have the standard dlc every car that is 1996 and newer are suppose to have it somewhere. But since you have an obd2 ecu I'll find you the diag steps for them. I'll PM you the info when I figure out how to send it to you.

kenskii

Thanks for the help steve :D Ummm yes i believe that to be true in America i think? I live in ireland i think the euro market didnt have it in every car till 99 or so?

kenskii

I literallly spent about 3 or 4 hours looking for it one day Im pretty sure its not there

kenskii

Ok so i have checked the loom for resistance and im getting .3 ohms on the signal wire .5 ohms on the ground wire and .5 on one of the heater wires. this shows to me there is prob no break in the wiring causing short is that correct? I couldnt find a fourth wire into ecu from heater tho is this normal? Also i tried back probing the o2 sensor yesterday and i was getting fluctuating voltage between .2 and .6 -.7v and when i test it today it seemed steady at about .5v? Seems like it was working yesterday and today its not working? could it have burned out? Also i seen some info suggesting to check fuse 15 but it was not blown. 11.8v on both test poles. also checked all other blade fuses they all seem fine.

kenskii

Ok i have now checked for continuity on the wires to earth. i plugged out the ecu first and checked to ground. no ground on any of them indicating no shorted wires is this correct? Have continuity on grn/blk wire or signal earth wire to battery ground when ecu is plugged in. tried a volt reading on the signal wire again today when the car was heated up. had a friend rev the car over 3000rpm for a few mins then took volt readings. it stayed under .1v when at idle then under open throttle seemed to climb .9v. This seems fine to me i think and also seems to point back to a short or open problem? What do you think? This is driving me crazy i keep going in circles

civic-steve-94

in my experience Honda wiring harnesses are pretty solid, the ohms readings your getting look correct. The fourth wire probably goes to a common ground. the jumping from .2-.7 is normal but should continue to do so all the time, the down stream or after cat should change less like.3-.5 but you shouldn't have two sensors. do you have a known good sensor laying around to test with or borrow from a buddy? do you have any exhaust leaks? hows the eld thing going? I would send you wiring diagrams but I don't know how useful that would be since its a euro car. also just to be totally sure all you did was swap the trans? no complications occurred during the swap?

kenskii

Would you mind sending them anyways so i have an idea of where i should have continuity should be/not be etc. The car has a honda of america chassis id plate on it so you never know Dont have a spare sensor i would have to order one. i think i have blown the sensor because i dont have any resistance reading between the heater poles on the sensor indicating its blown is that right? Im still suspecting an open wire or ground tho because the sensor and eld were working before and up to the gearbox change. literally straight away when we turned it back on i had two cel codes? and maybe in the mean time the sensor burned out because of it? The Gb swap went sweet like its m/t no problems only unplugged the starter motor and shafts, vss, reverse switch. only one wire i think we unplugged it was an earth wire going from the gb to the chassis i think and that was the first thing i thought of but i dno didnt seem to be a problem anyways... Should one of the heater wires have continuity with battery positive? the one that supplies voltage? ive tested the 3 other wires they seem fine i dont know where the yellow/blk heater wire goes to test that one though but im pretty sure i got 11.8v when test across 2 heater wires anyways... Or will i just order the lambda sensor? as far as the eld goes im not sure how to test that yet really.... still seems fishy to me that they both go at the same time?? which is why im so confused i dont know what to do next

kenskii

Has anyone got a wiring diagram for the o2 sensor? please??

civic-steve-94

how many o2 sensors do you have? yeah a trans swap is pretty to the point the ground is very important though, so make sure its nice and clean and tight. if you not getting and ohms reading thought the heater circuit of the sensor its most likely the sensor is to blame for that. I sent you a tech bulletin to see if that helps. it would be a lot easier to see it in person to help but that's kinda far way to just help diag a car, I guess I could got visit top gear too hahaha.

kenskii

Thanks for all the helf steve :D. am ive only one sensor i believe there was no pin in ecu for the secondary o2 sensor so i didnt even bother looking. im sure its not there... yes ok ill try an remake the earth connection just incase. ill order the sensor and attack the problem then... Would love ta see ya over here steve let me know if your going to make the swim over to me :D ha ha jk...

kenskii

So i got a new o2 sensor... Had a bit of trouble getting the damn thing off but its in and it cleared all my codes :D Thanks for all the help civic steve much appreciated. :D I presume that a dodgy earth after GB change caused the o2 sensor to short out and blow the sensor does this sound possible? Also i have one more question... Why did changing the o2 sensor clear the Eld code?? Obviously im delighted but i cant help thinking about it... Any one got any input?? any thoughts or ideas?

kenskii

Anybody?? Anyone at all??