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Discussion Starter #1 (Edited)
Help please! My check engine light came on a couple of weeks back. I used my CarMD (OBD reader) diagnostic reader on my 2003 330Cic and it gave a reading of po174 (only). So I cleaned the MAF and also found a tear in the oil separator hose going to the dipstick so I replaced that hose also. The check engine light would not go out at that time (my CarMD tool does not have a reset on it) so I disconnected the battery and crossed the 2 cables to reset the check engine light and the check engine light did go out but my CarMD (OBD reader) still reads as po174. Now 2 weeks have passed and the check engine light does not come on but my wife claims that the car will sometimes studder on take offs and does not have as much power as it did before the original check engine light came on. I drove the car and it seams fine but I do not drive it all the time. My CarMD reader still shows po174. :bawling: Does anyone know if this could be happening because I could not reset the computer on the car or is the po174 still the problem. (PS: I did check the CarMD reader on another vehicle and it read all systems normal without any po code.) :facepalm:
 

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Discussion Starter #3 (Edited)
Thanks for the reply

Sorry Ghost, I am aware that there would have to be better OBD scanners out there (knowing what I know now I do not think I would have bought the CarMD) but back to my question. If the scanner still reads po174 in my case above does the problem still exsist or do I have to get it reset? Also now that you mentioned getting a BMW scanner would the BMW scanner isolate the problem to be more specific of what the actual problem is within the reading of po174?:banghead:
 

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If the scan tool you are using does not have a reset button, then you have to wait for the car to turn the light off by itself OR get a scan tool that does have a reset button. (Why anybody would buy a scan tool that cannot reset is beyond me, but what do I know?) Anyway, all systems are constantly monitored, and if you really did manage to fix something then the light should go out by itself, eventually.

P0174 means Lean, Bank2, Sensor1.

There are are sensors mounted to the exhaust manifolds in front of the CATs. Your code is the sensor on the rear manifold is reporting that the exhaust gas does not have enough fuel in it, which is the same thing as saying the exhaust gas has too much air. Cleaning the MAF does not change the symptoms you have reported, which means the light will not be going off any time soon. Indeed, if you clean the MAF poorly there is a good chance you can make the symptoms worse.
 

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Discussion Starter #5
Thank you JdStrickland - oxygen sensor

Thank you for answering my question. By sensor1 does that mean Oxygen sensor #1 could be bad or malfunctioning? bank 1 and bank 2 appear to have an oxygen sensor, if it is a bad sensor is there a way to test the sensors?
 

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Sorry Ghost, I am aware that there would have to be better OBD scanners out there (knowing what I know now I do not think I would have bought the CarMD) but back to my question. If the scanner still reads po174 in my case above does the problem still exsist or do I have to get it reset? Also now that you mentioned getting a BMW scanner would the BMW scanner isolate the problem to be more specific of what the actual problem is within the reading of po174?:banghead:
You have to clear the fault codes after you have fixed the problem. Sometime fault codes, especvially misfire codes, can occur transiently. This doesn't necessarilly meant that there is a problem. but the faulty code will remain until you actively clear it using your scanner tool/software.
 
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