Obc

[Jrlbmw]

Hey guys my on board computer works, but it doesnt keep anything correctly so it doesnt work it always says -30 degrees celcius and the avg mpg after you reset it just goes down all the way. what im wondering is, what do i need, a new obc or something else im not aware of, thanks for any help

 

[Big Daddy]

Sounds like you may need a new battery on your SI board. Check this site:

E30 Net

 

[peteb3]

the temperature could also be due to your outside temp sensor being disconnected, check to see if it's plugged in or even there.
probably located in one of the brake cooling duscts if you have them.

 

[Jrlbmw]

I dont know if its the outside temp sensor thats broke but then again i have no clue where it is, i replaced the rear brakes today and there appeared to be something missing becuase there were wires leading to a sensor holder, I think big daddy may be correct on the si batterys because i tried resetting my oil/ service light, and it didnt work and the reasons they said it may not have worked is because the si batteries were bad, so im still lost.

 

[Jrlbmw]

it also says the tach and mpg guage are ran by the si board batteries, thats what gets me cause my tach and mpg guage work fine

 

[Big Daddy]

The sensor holder at your brakes is most likely a wear sensor for the brake pads. When the batteries starting going on my e30, the tach and mpg worked fine except that on occassion, not very often my tach would act erratic for a second than work fine again. My clock on my OBC would flash random numbers on occassion as well.

 

[Jrlbmw]

maybe it is them becuase like you just said my tach is kinda the same way it works but some times it goes wierd and erratic also then acts normal, so my guess is thats what it has to be because my obc doesnt work, my oil/service light wont reset, and my tach goes wierd so maybe ill change them and see what happens.