E46 Emissions warning Light

[Rootes]

Prior to purchasing my 2002 318i ci, 4 new coils and plugs were fitted. Since then the emissions warning light light has appeared twice.. the first time I had it checked on a machine, it came up as a cat fault but cleared once the check was completed. The second time I had it checked and it came up as fault no 10040 (unknown fault), again after the check it dissappeared. Since then I have serviced the car myself fitting a new air filter which was dirty, oil change and filter etc. Yesterday the light came on again, the car seems to run ok but the fault will not clear. Can anyone help!!!

[BMboy]

Specific to the BMW 318i (and in my sister's case - an 01 model), the mechanic didnt know what code 10040 meant. so i asked one of the leading BMW technicians in Perth, and he said something about the oxygen sensor - replacing it, as the undoc'd code 10040 is past the oxygen sensor. (so just replace it i'd assume)

if you chose to do a replacement yourself, you need to reset the ECM
this can be done by (AFTER replacing O2Sensor)
1) disconnect the battery - or just remove positive connection
2) step on your brake pedal for 10 seconds
3) and then re-connect the battery to the car
this should clear the ECM codes and data

hope that helped!

BmBoy

[Rootes]

Thanks for the info, really appreciate your help. Will buy a new oxy sensor and try and fix the problem

Cheers Mick

[DIONESE]

If you still have the code come back I would suspect the Map sensor, or just a dirty wire connection. the code your getting is a combined code indicating more than one issue is present. The computer may just need an update at a Dealer. Any code with lots of zeros means the local dealer needs money.