2000 Accord EX SULEV strange sequence of codes

[nmikmik]

My sister in law is driving a 2000 Accord EX with SULEV (Califonia emissions) decal on the window.
The reason why I am emphasizing SULEV is the fact that I suspect that is the main problem of this vehicle. Like a $300 O2 sensor instead of $80 for almost any other Accord. First we read ODB II codes when the eng light came on it pointed to Cat. Converter underperforming, so we changed the converter (big buck too). All was OK for about two hours and the light came back on…. This time it said something about the O2 sensor for heater sensor malfunction, so we replaced it too. Again everything fine for about two hours and the light comes back again. Anybody had a similar problem with that car before? Please advise.

[lorunner]

What was the code the next time?

If the sensor you replaced was the one in the cat than no its not unusuall. The O2 sensor is a delicate device and can be damaged so if it was knocked around than i can see it being bad.

[nmikmik]

Here is a better sequence of events:

1. Engine light comes on, we check the codes & it’s P0420 – Catalyst efficiency below threshold (Sorry I forgot to mention this the first time, It actually came back with total of 62 codes! But all of them said the same thing P0420)
2. We tried to clean EGR valve, still the same codes
3. We replaced the cat. and she drove for 2 hours to have engine light come back on This time though, engine was idling poorly and was almost ready to stall. We pulled the codes again and it said P0505 idle control something and P1167 – primary HO2 S no 1 heater system. This time we replaced the front end O2 sensor and the light went away, but it almost immediately came back with P1167, so we replaced the temperature sensor, the one below the distributor and the light went off for good – i.e. for another two hours.

This is where we are now. Dealer says to replace the EGR valve and the back end O2 sensor, but we doubt it will fix it.

[lorunner]

P1167 is the primary O2 sensor. given that the sensor you put in was good then thee may be a problem with the wiring going back to the PCm.

Just so we are straight you replaced the O2 sensor in the exhaust manifold. By the radiator?

The P0505 is a bad iac valve more than likely.

As for the 62 times that not uncommon to see. Its more than likely recording every time it was set.

[nmikmik]

Thanks lorunner,

Yes I did replace the o2 sensor on the manifold, and had a hard time finding the right one with long enough wiring harness, but I did replace it. The P0505 is gone, but it's still puzzling that when we reset the codes at the first arrival of the problem with the cat. - 62 codes came back practically immediately after resetting the codes. Is it possible to be related somehow to a transmission ??? She had transm replaced @ 105k it was kind of a recall, but they still charged her for the installation. Do you know where in the wiring can/should I look? Thanks!

[StealthSonic]

Hi nmikmik

I have the exactly same problem as you do, I'm still trying to solve it myself. I have everything down to O2 sensors. I haven't replace the harness yet but I you want to give it a shot try this.

On primary sensor (the one on manifold) trace the wires from sensor to the ECU behind the firewall. I heard it connects directly to ECU. Just have to replace the entire harness. I'm sure that's a least expensive thing to try.

Also I have 2 Accords and I installed the "supposedly" malfunction O2 sensors on to my other Accord a year ago and its still working until now, engine check light never comes on. Sometimes I think my ECU is going wacko and its giving out wrong codes.