P2243 & P3026 Fault Codes

[RWD FUN]

Pulled these code at a local parts store they indicated they were O2 sensor codes, but couldn't tell me which bank or pre/post cat (up-pipe/down-pipe)

Called the local dealer and they asked what tool I used to pull them. Said they didn't have any info on codes that start with a P. Said they needed to use the BMW scanner to determine the issue. I'm sure that service will be over priced for 2 mins work.

Did a search here and only hit on those codes was for O2 sensors from a couple years ago. No other real info about replacing them.

Car has 63K miles so I'm pretty sure they are not covered, even under the emission control mandatory warranty of 8/80K

Any one have these codes? Know which sensors to replace? And/or have a DIY on the easiest way to get to them. i.e top/bottom access, Panels to remove, etc

Thanks
Joe

[RWD FUN]

Sorry it's a 2008 135 so N54

[MightyMouseTech]

Originally Posted by RWD FUN

Called the local dealer and they asked what tool I used to pull them. Said they didn't have any info on codes that start with a P. Said they needed to use the BMW scanner to determine the issue. I'm sure that service will be over priced for 2 mins work.

WTF? All Powertrain codes begin with a P

[Freon]

Both are dealing with the heater circuit in the bank 1, sensor 1 oxygen sensor. I believe that's front bank, first sensor between the turbo and catalytic convertor.

P2243 - "Open circuit bank 1, sensor 1." This is heater circuit, resistance too high or an open circuit. It's either a busted/burnt out sensor (most likely) or the wires between the ECU and sensor are cut (less likely IMO), or the sensor isn't plugged in all the way (they generally don't magically work their way out over time due to the clips, but if you just replaced it and didn't push it in all the way to the *click*...).

P3026 "Bank 1 sensor 1 heater circuit not reached operating temperature." - Pretty much the same problem. I think it would be difficult to get P2243 without also triggering P3026 as they're tests of the same circuit, just different severity. A lot of sensors have an open circuit fault (current too low, resistance too high), closed/short circuit fault (current too high, resistance too low), then one or more "performance" based fault codes that deal with behavior over time (ex. sensor voltage does not reach X after coolant temp hits Y plus 5 minutes of running). This is a behavior over time one.

I'd go ahead and replace at least the one sensor, but because it's a PITA to get the downpipes out yo might want to do both the of the banks top/first sensors. I think the rear/lower/sensor2 position oxygen sensors are easy to get at, plus they're post cat and don't see as rough of a life, so you don't need to replace those.

Keep in mind the primary oxygen sensors are really critical to proper fuel injection. They are used to trim the fueling both over time and instantaneously, so it's not good to drive a car with a bad primary oxygen sensor. Get it taken care of ASAP!

I'm a DIY guy so I'd just do it myself. Sensors are not cheap, but labor is still probably worse. You can find downpipe install DIYs in the DIY subforum. It's a tricky task, though, not for a first timer I would say.

[RWD FUN]

Originally Posted by MightyMouseTech

WTF? All Powertrain codes begin with a P

Yeah didn't sound remotely correct when he said it. I mentioned that not sounding correct with OBD II requirements but wasn't going to argue. Just hung up and came here

Originally Posted by Freon

Both are dealing with the heater circuit in the bank 1, sensor 1 oxygen sensor. I believe that's front bank, first sensor between the turbo and catalytic convertor.

P2243 - "Open circuit bank 1, sensor 1." This is heater circuit, resistance too high or an open circuit. It's either a busted/burnt out sensor (most likely) or the wires between the ECU and sensor are cut (less likely IMO), or the sensor isn't plugged in all the way (they generally don't magically work their way out over time due to the clips, but if you just replaced it and didn't push it in all the way to the *click*...).

P3026 "Bank 1 sensor 1 heater circuit not reached operating temperature." - Pretty much the same problem. I think it would be difficult to get P2243 without also triggering P3026 as they're tests of the same circuit, just different severity. A lot of sensors have an open circuit fault (current too low, resistance too high), closed/short circuit fault (current too high, resistance too low), then one or more "performance" based fault codes that deal with behavior over time (ex. sensor voltage does not reach X after coolant temp hits Y plus 5 minutes of running). This is a behavior over time one.

I'd go ahead and replace at least the one sensor, but because it's a PITA to get the downpipes out yo might want to do both the of the banks top/first sensors. I think the rear/lower/sensor2 position oxygen sensors are easy to get at, plus they're post cat and don't see as rough of a life, so you don't need to replace those.

Keep in mind the primary oxygen sensors are really critical to proper fuel injection. They are used to trim the fueling both over time and instantaneously, so it's not good to drive a car with a bad primary oxygen sensor. Get it taken care of ASAP!

I'm a DIY guy so I'd just do it myself. Sensors are not cheap, but labor is still probably worse. You can find downpipe install DIYs in the DIY subforum. It's a tricky task, though, not for a first timer I would say.

Great info thanks. Close to what the parts counter guy said but much more detailed. Makes me feel confident that the heater on the front top sensor is the problem. Car seems to run OK, maybe a couple hesitations just after startup. I know it'll get worse come winter though.

I'll check DIY section for down pipe replacement. No way to get to that sensor to change without full removal I'm assuming?