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Discussion Starter #1
I have recently changed the upstream o2 sensor with a bosch oe, well actually i bought 2 like a dumb $%#$ thinking the problem was a faulty o2 sensor. But now im thinking it must be a wiring problem. The check engine codes are o2 sensor low voltage b1s1 and o2 sensor and heater circuit low voltage b1s1. does anyone know where the flaw would be in the wiring? has anyone had this problem before? Thanks
 

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Did you replace the correct O2 sensor. There are 2 of them. Bank 1 is the O2 sensor right on the exhaust manifold. Bank 2 is the O2 sensor right after the first cat convertor.

What trouble codes were pulled from the ECM?

If the problem is indeed the heater circuit it could be a wiring problem or the O2 sensor relay isn't working. Send me an e-mail at [email protected] and I'll forward the wiring info you'll need.
 

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the trouble codes pulled were 131 and 135 i have an obd2 i did a datastream on both sensors, the downstream b2s2 is fine it gives a reading the upstream has no reading. I had a mechanic do some work on the ecu one along time ago one of the wires had gotten chewed up by a mouse this past winter so im thinking it could be terminal 12 on the ecu. are the bosch sensors ok to use?should i have used kia?
 

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P0131: Front O2 sensor low voltage.

P0135: Front O2 sensor heater circuit malfunction.

Generic Bosch 4 wire O2 sensors are OK to use. I know folks who have used them successfully. However, if you check the kiausaparts site it DOES state that the part number for the front O2 vs the rear are DIFFERENT part numbers. I don't know why.

But it is VERY important that the generic sensors are wired into the engine wiring harness correctly. The color coding on the generic sensor is different than the factory sensor. One miswire will result in setting DTC's AND could damage the new sensor.

Here is how you should connect in the generic sensor to the engine wiring harness:

Yellow/white: O2 sensor plus.

Blue: O2 sensor minus or ground.

Light green/red: either heater wire.

Blue: either heater wire.

Match the wiring from the generic sensor as shown in the instructions that came with the sensor.
 

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Oops...I forgot to look up pin 12 on the ECM. Yep, that is the yellow/white wire for the front O2 sensor plus input. If that wire is broken it explains all. You need to repair that wire.
 

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Discussion Starter #6
well i looked at the ecm and everything was fine. So i went back to the sensor its brand new so i figured that thats not the problem, wrong! I bought a bosch oe wich was direct fit no splicing needed, wrong! Thanks to axe man i figured the color codes out. well on my 99 sportage i have a blue, yellow, light green, and red the blue is the ground the yellow is the signal and the green and red are the heat wires. if anyone buys the bosch upsteam sensor the two blacks are the heat the blue is the signal and the white is the ground.
 
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