ecu communication issue

[thedude60126]

Hello everyone well I picked up my first e39 (have owned 6 e36's). Its a 2000 528i stick. When I got it had a airbag light. Hooked up my scanner tonight to read it and its telling me that it can't read the ecu. Any ideas or tricks what might be causing this. Thanks

[JimLev]

Did you have the key on position 2 and the cap on the diagnostic port under the hood?

[thedude60126]

yep diag cap is on and snug and the key is in position number 2

[JimLev]

What scanner do you have? Does it use it's own battery or take power from the port under the dash?
If it has it's own battery check to see that you have 12 volts at the connector.
Also clean the male and female pins in the port under the hood. Commas from the OBD port under the dash go thru the connector under the hood and then to the DME.

[thedude60126]

Ok will check connectors it's a Mac tool scanner for all models have scanned other bmws with it and it does pull power from the port so I know that works

[Spirit Force]

Are you trying to read airbag codes or DME codes? If the car under the hood 20 pin round diagnostic port you need to use to read airbag codes. It was from model year 2001-> that the under the hood diagnostic port was deleted and under the dash diagnostic port got full access. In any case BMW recommends you to always use the 20 pin round diagnotic port for full access.

[thedude60126]

I see makes sense so since because it's a 2000 my ob2 scanner won't get full access I have to use a tool for the under the hood cool

[JimLev]

Right about reading the airbag from the 20 pin port under the hood, however your Mac tool should connect to the DME to read everything else.
Becaues the 16 pin OBD port connects thru the 20 pin port you may have connect problems with the 20 pin port too.

[edjack]

The Multiple Restraint System lives on the K-bus. Your Mac tool needs to be able to interrogate that bus, off the cluster.

[thedude60126]

I have a much simpler cel only scanner I am going to try connecting that to the car and see what happens.

[rf900rkw]

Ah, no. Access the SRS on a BMW will require a BMW specific scanner. If this "Mac" scanner has the full Euro package, and the BMW 20pin, then it will do it. There is nothing you can plug into the 16pin port that will.

[thedude60126]

Yep thats what I figured. Good news is that there is a 20 pin connector I can get for my scanner :)