BAD OXYGEN SENSOR PO137 CODE>>LOW VOLTAGE BANK ONE< SENSOR 2

According to the code the issues can be the down stream heated oxygen sensor or wiring from sensor to vehicle's computer. In other words, from the sensor to four wire electrical connecters, wiring circuit is open or electrical connector at computer is damaged or corroded.
Let me know if this answered your question or if you have any other questions. Talk to you soon, Ty

Hi TY
Thank you for your quick response..the electrical connector (4 pin) is in a very difficult spot to reach on this kia sportage..its a downstream O2 sensor. I will check what you told me to check..
I'd also like to ask, according to the code displayed, the car is running too lean..would a clogged or bad fuel filter give the same code?
I will check the wires and connector..this is the 2nd sensor and its giving a PO137 and also the guy said something about another code=heater.
Thanks so much for your help!

Ty
sorry to bother you ,but where is the computer located on this car..it looks like there are a few different. ones under the dash..but not certain where the main one is that the downstream O2 sensor goes to...Could a bad fuel filter cause it to give this cade, or is the code specific for an OXYGEN SENSOR..it said banl 1 , sensor 2..replaced the downstrem 2x as I said, still the check engine lite is on..its really hard to reach the connector..next to impossible to reach..any help appreciated.

RE: 1998 KIA SPORTAGE 4 dr. automatic trani, 2.0 liter engine..code PO137
CHECK engine lite on

It's not a problem! The ECM (engine control module) is located below the right side of dash under carpet.
The fuel filter would not just cause the P0137 fault code only it would cause a lot of other codes as well as drivability problems.
If you can see the downstream wiring check for any damage to the wiring. Then disconnect the negative terminal from the battery and check the wiring coming into the computer because it sounds like it would be easier.
Some more questions
Have you checked the o2 sensor fuse in the under hood fuse box it is titled "o2 sen"? Does your vehicle have an exhaust leak (ticking sound on a cold start that decreases in sound when warm).
Talk to you soon, TY

GOOD MORNING TY
very hot here in Florida. NOt good temp to work on cars!! in Florida. I looked under my 1998 KIA sportage hood for the fuse box u told me to check for the PO137 ERROR CODE..check engine liight on. YOu said to check O2 sensor FUSE, but all I see are the following: I see EGI MAIN, FUEL PUMP, FUEL INJ, ADD 30 amp.MAIN 80 amp, BTN 60 amp, IGN 40 amp, P/window 40amp, then MAIN 15 amp, ABS 30amp, and HEAD 20 amp. THE EGI MAIN AND FUEL PUMP look like relays. The rest look okay.
I just hate to keep spending $ on O2 sensors. I also don't hear any exhaust leaks. The rear tailpipe fell off, but we had it replaced. The exhaust shop didn't say anything about a ln exhaust leak.

Someone else told me to check the COOLANT TEMP sender..what would that have to do with a PO137 code?
The wiring looks too complicated for me ..I found where the computer was..just like you said, but you can't see the wires..I have to remove everything. If I undo the battery, will it clear the check engine lite? As I said, the auto store cleared it, and the code came back a few minutes later while,driving.
thanks for all your Help..Gail

TY I took it to a shop..put it on a ift..they said the new downstream O2 sensor had NO voltage going to it..just like oyu said, its something in the wire harness or computer itself.
There is suppose to be a PASSENGER SIDE fusebox with 02 sensor fuses in it..I can't find the location ..I see the one under the hood and the fuse box on drivers kickpanel, but I can't find the box on Passenger side with O2 sesor fuses....wanted to check them..do u know where I can find that box..I see the ECU under the carpet on passenger side, but NO fuse box..any help appreciated.

The information I was provide called the fuse box "passenger fuse box". It is located NOT on the passenger side as I thought from the name but on where you found the driver side kick panel. According to the wiring diagram for the o2 sensors there are several fuses titled:"meter","ecu","fuel pump","o2 sens", and another "o2 sens". All of these fuses are 10 Amp fuses. The wiring diagram shows one ten amp fuse for each o2 sensor. Check for power at each fuse terminal (with fuse installed). To test the wiring it best to start at one end of the circuit and check for power. If there is no power then you half the wiring and test there. Doing this will narrow your search for an open which I think you have here.
Check for both of the fuses for the o2 sensors then test wiring. If you need more help let me know or how to test the circuit with a electrical tester (multimeter, test light). Talk to you soon, TY

Hi Ty..yes, I found the fuses jjust as you said on the drivers side. The both O2 fuses were good, as well as the ECU fuse. Can you please explain in simple terms how to check them. Do you have to have key one, or just accesory key on and what and how many volts are you checking..many thanks.
The mechanics said it would be too costly to fix and trace the open, but hopefully I will find a short or open as the downstream O2 sensor is getting NO voltage..they said it would be ok to drive but gas miles might be affected.

I have a multi meter and test lite..you also said to leave fuses in.??
thank you so much for all your help. I think this is gona be a hard on to fix unless I was a Master mechanic like you.
Alos, excuse any typos..this keyboard doesn't work well.
Thanks so much! Gail
we have a brutal heat wave here (florida)..phew

To test for power at the o2 sens fuses turn your key all the way on with out starting your engine. Set your voltmeter to direct current and place the negative probe on the inner wall of a power outlet or cigarette lighter (assuming your power outlet has power and ground) and your positive probe on each metal tab on the top side of the o2 fuses. If your meter reads battery voltage (12.9 +/-1.0) you know you have power to the fuses and on each side of the fuse. Then check for power to the rear o2 sensor. run a wire tied to the neg. battery post to your neg meter prob then place pos meter probe on the blue wire w/a green stripe and check for battery voltage. If good then this is where it gets more complicated. Turn the key all the way off and disconnect ECM computer electrical connector switch you meter to continuity and check pin no. 39 it is a solid blue wire and ground (ie power outer wall). If no continuity found then the only thing left is a damaged electrical connector pin either on the 02 sensor or ECM computer which is difficult to test w/o specialized electrical terminal tools.
Hear is some diagrams for your vehicle.

Hi Ty..i really, really appreciate all your help. Assuming you are using the inside of the cig lighter as a ground, the meter is reading a weird voltage =177mv on both 02 (10 amp fuses). I am putting the red positive end of test lead on top of each O2 fuse..Unless I am not connecting the leads right, something doesn't read write as voltage?????
I may retry again as it raining

Happy Labor day, TY..sorry to bother you but do email when u get a some free time. I put the car key in the "ON" position and still get @ -177 mv (that is a MINUS) on all 4 metal tabs of BOTh O2 sensor 10 amp fuses. Its so hot its next to impossible to do anything in this heat..I had my meter on battery load test 12 volts when I used it. I don't know if these readings are bad or what is causing this. I will use a second meter and recheck again..thanks!

That doesn't look right to me. If your unsure about the ground on the power outlet you could run some wire right off of the battery ground into the driver side. Is there is way you could send a picture of your meter or a website that shows your exact meter? There are so many meters out there.
According to the wiring diagram you should get battery voltage with the key on at the fuse terminals. Let me know and we'll go from there.

Ty I tried another meter (CENTECH)..attached black wire to COM, and red wire to VohmmA.
I hope that is correct. NOW i get zero volts on BOTH 02 sensor fuses..in all 4 locations. What could be causing this?
Gail .I set the meter on DC 20VOLTS

TY looks like the fuse pump RELAY turns or passes 12 volts to both o2 sensor fuses
is the relay bad? or does car have to be running to check for 12 volts at these fuses ?

Yes, the fuel pump relay supplies power to the o2 fuses, You might be able to swap the fuel pump relay with another one (in the under hood fuse box). If there isn't another matching relay (5 pin) then you'll need to jump the relay (bypass the relay by completing the circuit with a large wire) then you can check for voltage at the o2 fuses. Let me know how it goes, TY

Hi TY
The 2 kia sportage relays were the same part # and both 30 amp. I swapped them out as you said..still no voltage to both O2 sensors FUSES.
I really appreciate all your help here. My dad was a service writer and passed away, so I miss his help fixing cars. I hope with oyur help we can figure this out.
Gail

TY, do u have any idea what could be the problem on this ? Where does the power come that comes into this O2 sensor fuses..from the battery or computer?
I don't know
where else to trace,..does this mean the 2 connectors to the sensors themselves aren't getting 12 volts??
thanks

You should be getting power on to the o2 sens circuit from the fuel pump relay. The fuel pump relay under the hood supplies power to the fuel pump and also the o2 sensor fuses. Here is a wiring diagram that shows the path of power (highlighted). You may have an open any where between the fuse box on the driver side kick panel and fuse box under the hood specifically on the black wire with blue stripe. It looks like there is possibly a splice within the under hood fuse box that supplies power to the o2 sensor fuses.
Here I attached the actual diagnostic steps for P0137 fault code titled "98kiasportageP0137"
Pay extra attention to the blue wire it mentions. Although I don't talk about this blue wire above I find it odd at there is no power to the 02 sensor fuses.
Try these steps and then let me know if you have any questions, TY

TY. YOu said you attached diagnostic steps, but I don't see anything..just 2 pictures of wiring. Can you send me that attachment "98kiasportagePO137"?You can send attahcemnt to: [email protected]
that is my email..thanks
I will have to trace that blue/black wire you mentioned. Does the car have to be running to check O2 Fuse power to both fuses, or just run position(key)
thanks

too hot to work on it outside!!

TY
okay, I decided to try to check both (1998 KIA SPORTAGE) O2 sensor fuses with car RUNNING and both show voltage in all 4 spots(metal tabs). When ignition switch is is the "RUN" position, there is NO votage to both O2 sensore fuses, but with car running, there is voltage to both O2 sensor fuses..don't know where to go from here.
Thanks

Ok, Good your getting power to that side of the o2 sensor circuit. Now let focus on the other end.
Sorry for not making sure I sent the diag steps. It's complicated so I'll translate the steps to take.
1 turn key completely off, disconnect rear o2 sensor 4pin electrical connector and computer 88 pin connector. Switch your meter to continuity (looks light sound waves picture) Place positive probe on pin 39 (pic I gave you on the computer electrical connector) and neg. probe on a ground ( power outlet wall or run a wire to the battery neg terminals). There shouldn't be any continuity if there is there is a short to ground on the blue wire running from computer to rear o2 sensor.
Start here and let me know how it goes, TY

Ty..You are saying to disconnect the rear O2 sesor 4 prong connector, and also disconnest PIN 88 on ECU..there is nothing to disconnnected at pin 88 according to my wiring diagram..??
I know how to do the continuity test..my meter has an adio so I can hear it if htere is continuity.
I just need help on the ECU pin 88
The car has to be jacked up to reach the rear O2 sensor..its in a horrible spot way , way up against automatic-trani.
thank for all your help so far!

Sorry for the poor wording I meant the computer electrical connector (it has 88 holes for electrical pins on the connector it self).
You'll need to disconnected the o2 sensor or the continuity test will run through the sensor and give a wrong reading. All you're checking for on this test is a short to ground. So when you measure from the computer pin (#39 pin blue wire) to ground your meter shouldn't show any continuity. Talk to you soon, TY

Ty. sorry to bother you..have a couple questions. when car is running (1998 KIA SPORTAGE), i told oyu i get 12 volts to both 02 sensor FUSES. does that mean that the oxygen sensors are getting voltage up to where the connection joins (from end of sensor to 4 wire connector where it plugs into harness?
Also, if I check voltage on the engine side connector (blue/) where does that voltage come from? The ECU? Do I have to have the car runnning?
I will do the continuity test when this weather cools down here..thanks so much.
Also, how come no voltage to both o2 sensor fuses when the car wasn't running ? just wondering.
THANK you so very , very much for ALL your help and all your replies..it means alot to me.
I hope we can solve this eventually! Gail
I will let you know!

Power is supplied to the o2 sensors only when the engine is running so that is why you have power when measured with a meter at the fuses (because the engine is running it would be more like 14 volts due to the charging system).

You measure only at the fuses so all you know is there is power to the fuses.

You'll need to measure at the rear o2 sensor electrical connector to know if power is being supplied to the sensor.

Continuity test is done with the engine off ignition key off and removed from lock cylinder.
Follow the diag I sent prior to this and get back to me.
I hope this answered your question, TY

Hello TY..okay, now I have 2 other CODES showing..a PO141 (HEATER CIRUIT) AND A po103 mASS FLOW AIR FLOW A CICIUT high
i DON'T KNOW IF THIS COMPLICATE THE SITUATION OF ONLY HAVING A po137 (LOW VOLTAGE DOWNSTREAM SENSOR 2).

i STILL HAVEN'T BEEN ABLE TO DO A CONTINUITY TEST AS i NEED A LIFT TO REACH THE CONNECTOR TO REMOVE IT FROM THE DOWNSTREAM SENSOR.

wHERE DOES THE 12 VOLTS COME TO THE )2 SESOR..FROM THE ecu COMPUTER?

aNY INFO APPRECIATED..i AGREE WITH YOU THERE MUST BE AN OPEN..THE OPEN SHOULD SHOW no CONTINUUITY, CORRECT IF ITS OPEN?
THANKS
gAIL

This vehicle only had one code to begin with p0137 right or did the other codes exist also? Because, removing fuses and disconnecting electrical codes can and will trip more fault codes to show up. So if it is just the initial code you gave me let's stick with that code only.
A four wire O2 sensor is supplied power from the battery for the heater circuit only on the Green wire with a blue stripe. The other three wires all go back to the computer.
The Black wire with a red stripe is the ground side of the heater circuit for the rear most oxygen sensor. The computer controls when the O2 heater turns on and off on the ground circuit.

Hi TY..originally the 98 kia sportage only had a P0137 code. Now it has the 2 others (po141, and Po103). I am sorry I didn't get back to you but have been sick, so wasn't able to diagnose this car problem.
I think I undertsand what you are saying. You are checking for continuity from rear (DOWNSTREAM) O2 sensor connector to pin 39 on ECU. I see in a wiring diagram that the oxygen sensor has grounds at the ECU on pin # 10 and pin #30, both grounds.

Do I need to check all 4 wires for continuity or just that one blue wire at pin #39 at ECU.
**there should be continuity if the wires are good, correct? And no contnuity if there is an open, correct?
I am a bit novice at electrical, so bear w/ me.
Also, does the BATTERY NEGATIVE post have to be disconnected to remove ECU 88 pin connector?
Thanks..I think I am getting what you are saying!