[kewlmike]

I have codes p0135,p0141. Both heater ciruit malfunctions.
I removed the fuses and Ohmed the ciruit side of the fuse thru the heaters on both front and rear to pins 30 (rear) and 31 (front) at 211 connecter at the ecu,ecm..whatever they call it on that.Both pins have 3.5 ohms indicating a clean circuit,considering the heater itself at 2 to 4 ohms.Id like to know what pins connect those pins to ground when you start the engine,my rear heater has no ground when running..Both the front grounds at pin 37 and heater operates.I searched kiatech with no luck...ive tried swapping ecu's.pin 28 on 211 has a good ground to b-.
thanks for your time

 

[DavesSpectra]

Do you have voltage to the heaters when the ignition is on?
Most O2 sensors do not have switched ground legs...If your secondary O2 sensor is missing a ground on the heater leg then provide one.
There should also be voltage on the ground leg "if" the ground is truly missing.
Both O2 sensors may use the same grounding point.
Dave

 

[kewlmike]

thanks for helping

there is 1 fuse each for each sensor,both hot at all times,each have seperate grounds at the ecu..frt sensor at connector 211 pin 37,rear at pin 30. 211 is the ecu connector.
I believe the ecu reads the ohms on each when you turn on the key/start.thats how it knows if there is a fault on either o2 sensor heater circuit ( p0135,p0141 I think )then if the heater is not active i think you will have other codes due to inefficiency. I think..lol.
Can you tell this has given me a fit?

 

[kewlmike]

btw,the front sensor works ok .the ecu provides a ground for it.I have checked the ground with my ohmmeter..not until you start it though..until then pin 37 is open

 

[GottaCruise]

Greetings,

If still no joy, maybe this post will help:

http://www.kia-forums.com/1g-1994-2002-sportage/73589-2002-o2-sensor-trouble-codes-check-2.html

 

[DavesSpectra]

GottaCruise...
Thanks for the link....I'm still learning and will till I die..
I have read about posters getting the p013A codes and never knew that i was a programing error in KIAs ECM ...Should be P0140...Interesting.
To the original poster it sounds like a bad ECM and I don't like saying that as too many are replaced for no reason. If you can get a ground on one sensor but not the other at the ECM then it is probably a bad transistor (internally) not pulling the bad line to ground. I was aware of actual grounds on the O2 sensors BUT they must ONLY be for the actual sensor portion and not the heating resistor side. It does make sense as the ECM then could "check" the resistor for continuity and voltage present (+12v). I hope you can find a "test" ECM (borrow one) to confirm diagnosis.
ECM failure is usually not that common.
Dave

 

[kewlmike]

Thanks SO much Guys !!

That thread i was referred to hit it on the nose...I was assuming the fuses were supposed to be hot with key off,because they were.I couldnt understand it untill i checked the ecu and found the ground end at the ecu..then it all made sense to me ( I thought ).
the other thread told of anothers problem after changing out a "switch".
after thinking a little i realized the switch was a relay..the fuel pump relay which looks like a good ole standard bosch 30 amp..actually had 2 pins normally open,instead of the center pin nc.
This drove me crazy.i couldnt find the schematic for the heater circuits on the o2's.
again.
THANK YOU
Dave
GottaCruise

 

[GottaCruise]

Congrats on the repair, and kudos for hanging tough & doing all the checks / cleaning ground points, etc.. - good diagnostics there.

 

[aquanaut20]

Glad you have it fixed, good diagnostics always pay off.

Sorry! ..Wasn't able to contribute till now..... Philip