Diagnostic comms vs scanner comms - United Bimmer Community

**NT15MCP** · 07-25-2010, 03:20 AM

I have a question about the communications bus on a 2003 330Ci (American). I wanted to turn off my Daytime Running Lights option. An independent shop connected their diagnostic tool/ passthrough programmer to my car and told me that they could not do any diagnostics or programming because I had a communications error. They said typically the comms error means that one of the 40 or so control modules is bad and the only way to figure out which one is bad is to unplug them one at a time and attempt the diagnostic tool again until the comms error clears... at the cost of about $100/hr plus the $90 they want to connect their tool. I went to Autozone and had them connect their "Check Engine Light Code Reader"/scanning tool to my car which connected just fine to the DME and told me there were no codes.
That's the background, here's the main question:
Does the generic scanning tool use the same communications bus as the diagnostic tool? I've read somewhere that if the diagnostic tool doesn't have the right software you will get a comms error. If the comms bus is the same for both, then I can have the dealership connect and reprogram the light switching control module, if it's a different bus then I don't want to waste $120 at the dealership just to hear them tell me that they will troubleshoot for roughly $100/hr in the same manner as the independant shop.

Thanks for any help

**HyeTide** · 07-25-2010, 08:50 AM

Quote:

Originally Posted by NT15MCP

I have a question about the communications bus on a 2003 330Ci (American). I wanted to turn off my Daytime Running Lights option. An independent shop connected their diagnostic tool/ passthrough programmer to my car and told me that they could not do any diagnostics or programming because I had a communications error. They said typically the comms error means that one of the 40 or so control modules is bad and the only way to figure out which one is bad is to unplug them one at a time and attempt the diagnostic tool again until the comms error clears... at the cost of about $100/hr plus the $90 they want to connect their tool. I went to Autozone and had them connect their "Check Engine Light Code Reader"/scanning tool to my car which connected just fine to the DME and told me there were no codes.
That's the background, here's the main question:
Does the generic scanning tool use the same communications bus as the diagnostic tool? I've read somewhere that if the diagnostic tool doesn't have the right software you will get a comms error. If the comms bus is the same for both, then I can have the dealership connect and reprogram the light switching control module, if it's a different bus then I don't want to waste $120 at the dealership just to hear them tell me that they will troubleshoot for roughly $100/hr in the same manner as the independant shop.

Thanks for any help

My comm bus has different pins than the scan tool, can only reset oil light with the comm bus. Dealer wanted $50 to turn DRL off. If you are having other work done and ask real nice

they might do it for free?

**NT15MCP** · 07-25-2010, 03:59 PM

Do you mean that the comms bus pins are a different set of pins on your scanning tool compared to your diagnostic tool, or that your diagnostic tool has more pins than your scanning tool?

**HyeTide** · 07-26-2010, 02:39 PM

Quote:

Originally Posted by NT15MCP

Do you mean that the comms bus pins are a different set of pins on your scanning tool compared to your diagnostic tool, or that your diagnostic tool has more pins than your scanning tool?

My comms bus has 9 pins, scanner has 6, but there is one pin on scanner that is not on comms bus?