Can an ECU be reprogrammed? I have the above DTC in my Kia and have done all the sensor replacement and point to point wiring checks, I am convinced the two ECU's I have tried have the same problem and need to be reflashed/reprogrammed.
P0141 is a heater code right? If ECU's are burning out driver circuits, it is unlikely a reflash will solve the problem.
What year/model Kia? How many miles on the car? What sensor(s) did you replace?
Two ECU's would seem to indicate the problem is NOT with the engine computer.
P0141 basically means the rear O2 sensor heater is not working. It could be a wiring problem or a bad sensor, or a number of other things.
First thing to do is to verify 12 volts for the O2 heater at the plug for the rear O2 sensor. On the plug to the O2 sensor there are probably two white wires, those are the heater wires. On the vehicle harness side match up the two wires that connect to the white wires. Unplug the connector, have a helper start the engine and measure for voltage at those two wires on the vehicle harness connector. Check as much of the wiring as possible for damage, usually the wiring for the rear O2 goes up into the cabin through the floorpan so only a short section of it is exposed.
I think Kia(and Bosch, and Denso, etc) all recommend that the 4 wire O2 sensors be replaced at 100k. It is my understanding that the rear one isn't as critical as the front, as it only checks to see that the catalytic converter is functional, and depending on the vehicle that test is only done once per drive cycle leaving the rear O2 basically doing nothing the rest of the time aside from throwing back a reading that it in line with, but of a lower magnitude and slight time delay than the front O2 sensor.
Chris
Thanks for the replies guys. I am at wits end with this DTC. I have done the point to point wiring check including continuity to the ECU from the heater connections. Both sensors are new and that is why I theorized that both ECU's might have gotten somehow...how do I say...curropt. Wanna buy a 2001 Sephia?
I heard (I have not personally verified this information) that the wiring on the 'OEM' replacement oxygen sensors sold at autozone/ checker/napa are not wired correctly for use in your vehicle. The pins are supposedly out of order on the connector, rendering the sensor inoperable and throwing an DTC as a result. You may want to look into this, I don't have a wiring diagram for a 2001 sephia unfortunately, so I can't help you any more aside from bringing this up.
Kia took it on themselves to redesign several aspects of the mazda components/designs to make said designs proprietary, the O2 sensor deal may very well be one of those things that was 'changed' just enough to make the aftermarket stuff not work. Another example of this is the 5 pin relays that Kia uses. They are rotated 90 degrees internally, and while the orientation of the blades on the kia relay is the same as a standard 5 pin relay, and a standard relay will go right into the socket, they are NOT the same internally. I found that one out when my fan relay died at 98,xxx.
Similar things have been done to the valve cover gasket for 1996/1997 engines, the replacement gasket sold by autozone/checker does not fit, they list the same part for the mazda miata, protege with 1.8, sephia, etc. The sephia is different, and only the dealer gasket is a direct fit.
Chris
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