[yamaha]

Background: I've been using the Bosch oxygen sensor's from Advance Auto Parts for my Elantra and Tiburon. Both had the same codes, after replacing the front oxygen sensor with a OEM one on the Elantra, the code went away. I bout a OEM front oxygen sensor for the Tiburon, but needed to extend the wires four inches or so. The same issue is persisting.

I attempted to solder the wires together the best I could, but being that they were Steel, it wasnt happening. There are only four wires, three of which are the same color, black, grey, and white. I went wire for wire, assuming nothing would be an issue.

Is it possible to switch the two heater circuit wires and have the same issue. Apparently the car will only heat up the oxygen sensors for the first minute of run time. I'm at wits end on this one.

Help!

[yamaha]

OK, lets get alittle more in depth and try to fix my problem. Originally, when I bought the car from the previous owner, the secondary oxygen sensor was spliced into the wiring for the primary oxygen sensor. It was spliced in on the sensor side, and not the ECU harness side.

I've used both Bosch replacement and OEM sensor's with the same two codes. I finally got more in depth and got out my ODBII software from Jay-M. At idle, the car is reading 0.1-0.475. When I start to drive the car the voltage will drop to 0 and stay there. I compared results from the Tiburon to the Elantra.

The Elantra will fluctuate between .475-.715, and around the same while driving. The only other problems I can figure out is either the ECU has a bad circuit board on it or there is a wiring issues. I have to get out the trusty multimeter and check the harness side for voltages, but this is driving me INSANE.

HELP!

[DTN]

I had those same readings with a bosch. I got a stock sensor and the problem went away. that voltage reading is in the middle of the high/low changeover for the tib. It's the wrong sensor and advanced will realize this one day.

[yamaha]

The thing is I tried BOTH Bosch and OEM replacement ones, and the same issues. I tried another ECU tonight, but that didn't seem to help either.

[HyundaiKitCoupe]

i have the same problem, along with daniel_depetro. p0133 and p0137 are mine. "low voltage". I tried everything up to 100% rewiring over and over again, starting from scratch, official wiring scheme, soldering passionately, and the codes persist. The next thing I'm going to try is resetting the ECU using the disconnecting negative battery terminal method.

http://www.rdtiburon.com/index.php?showtop...mp;hl=emissions (post #3)

seems like DTN and Bullfrog are the only ones who are helping us out. Nobody else is interested or seems to know what's going on.

This post has been edited by HKC (HyundaiKitCoupe): 14 May 2008 - 10:01 PM

[DTN]

still waiting on your graphs HKC.

[HyundaiKitCoupe]

damn lot of stuff i had to take care of for school, and i got sick for 1 week (don't even know how, plus i felt so great), now i just got the computer back and charged but i'm flying out today so i won't have any diagram until i get back.

i'm real sorry for myself though, hope you guys figure this out soon. if not then i'll get back.

[DTN]

here's something interesting...

It says here that the colors of the o2 sensor wires are the same from the ECU as to power. If you flipped them around, it would have a different reading then if it were not. You should check the wiring and try flipping around the sensor wires... The R/W on this schematic.



pins 3 and 4 on rear o2 sensor.

[yamaha]

I'm not following your post. I checked the Ohms on the heater at room temperature, and it was 2.6. HMA states as long as it's under 30 Ohms at 750 degrees or under it should be fine. I'll try to flip the heater wires around, but I doubt that will solve much. I'm going to need to check for 12v on both sides of the heater and go from there.

[DTN]

no, not the heater, the sensor wires.

[yamaha]

Just checking.

I'm going to trace the wires from the ECU to the connector, and then try to flip the wires.

[DTN]

Just get under the car whereever you did your splicing of the wires before and switch the same color wires around.

[yamaha]

I switched both the white wires around, same thing happening. I also tried switching the black and grey for shits and giggles, same thing happens. I did unhook the primary oxygen sensor and the ODBII software was reading a constant .475. With the oxygen sensor plugged in, I was getting ups and downs betweek 0-.475. I tried both the old ECU and new one and same problem persists. I'm leaning towards a bad connector plug on the harness side. There is some slight damage, meaning the plug slides in to easy and the clip will not hold the molex plug from the oxygen sensor firmly. Thoughts?

[Jay-M]

You mentioned that you were going to swap the ECU from the Beta accent and see if the ECU is the culprit? how's that going?

[yamaha]

Did that, nothing.

[Jay-M]

check the continuity of the wires from one end to it's other end and see? if the ECU and o2 sensors swap did nothing, then it might be the wires