Rep Power: 0

My 04 Civic EX has an 02 engine & rebuilt tranny. I have a reoccurring p0135 code. I'm on my third one. It 3 & 4 post still test between 10-40 ohms (12+) I've followed the shop manual, I'm getting voltage & continuity with each step and it's stating my next step is to swap it with another ECU. I know it has an immobilizer.

Would I have to swap the ECU, ignition assembly, and the key from another 04-05 in order to test that, or not all 3? It wasn't very specific with the "Test for Voltage" when going through the 4 pins and ground body, I was getting around 12v's though.

It also has a rough time starting, in cold or hot conditions, I've checked fuses & relays and the code above is the only code I'm getting, so considering the starting issue it still leads me to believe the ECU. By rough start I mean I'll have to crank it a bit with the gas pedal depressed to get it to start. Also, if I remember correctly it was difficult to start before the engine swap, again leading me to think the computer.

Appreciate any answers to my questions about my car. It's been a nightmare of a year for the car and I really just wanna set it on fire and get a Toyota. I just can't figure it out for the life of me, so I give up trying to figure it out and ask some of you self-made pros

 
Rep Power: 368

are you using the original 2004 O2 sensor or the donor 2002 sensor?
2002 is narrow band, 2004 is wide band.

call a lock smith to program your current key to the new ECU. Old ECU will have the programming i would guess

 
Rep Power: 0

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I just replaced it last week, Bosch Part # 15733, because the other one tested @ 9ohm, so under 10. This new Bosch tested before and after installation @ 12.

I did not know a locksmith could reprogram my key to another ECU, does he need the VIN of the other car if I end up taking it from a junkyard? If so I'll make sure to jot it down. Is there something I should mention when calling around to make sure they have the equipment to program my 7th gen specifically?

 
Rep Power: 223

Can't use Bosch needs to be Denso.
Do you have the original 04 computer? If so then you need the wide band o2 sensor DENSO 2349017

 
Rep Power: 0

10-4 will update as soon as I get the new part soon.

 
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I've gone through 3 sensors all defective reading less than the OEM spec of 10-40 ohms of resistance between pins 3 & 4. Am I missing something? I've put them in anyways, confirmed bad. The first one was from a local auto parts store, the second two were from amazon distributors. The only other option I see is spending nearly 1/4 the value of the car to get the sensor from majestic honda which doesn't even seem worth it anymore. This car's been nothing but nightmares, idk where to find a good, in-spec DENSO 234 9017 oxy sensor.

 
Rep Power: 127

If you haven’t been spending the $100-ish on a sensor, you’ve probably been buying the fake ones. The proper sensor is expensive.

 
Rep Power: 0

I'm aware of the fake ones and the ones for the 01-03 range.I mentioned the part # I was getting, around 200 bucks each purchase.

 
Rep Power: 368

at this point, get to a scrap yard and get some used sensors to test.
car-part.com have listings on nearby yards
need to be 04-05, EX to fit your car

 
Rep Power: 223

Tried rockauto?

 
Rep Power: 0

I have, they almost always have the exhaust header cut off with the sensor removed along with the muffler..... I've checked a few, always disappointing I assume it's just easier for them to remove the cat. for legal disposal processing?

Will check it out, appears to be around the same price for the "DENSO 2349017" wide band sensor I need for the 05 ex in question.

Will update when I have information.