Bit Serial Data Interface Bmw X3 Series Cars Or

Judging by this attached diagnostics procedure, once you have verified your wire integrity from the DME to the water pump, it would indicate a failed master (DME).

The coolant has been replaced with a Pierburg new pump (fault was present before coolant pump was replaced).

When the coolant pump is unplugged the LIN bus has about a 1 volt square wave on it, and when the coolant pump is plugged the bus stays at battery voltage with a lot of noise.

I am having trouble understanding if this is a dedicated bus to the coolant pump, or what other components share the bus.

One note refers to it as a B.S.D.

A different diagram show the coolant pump connected to the battery sensor, fuel tank pressure sensor and the air catalyst sensor (this vehicle does not have an ozone reduction radiator).

I have unplugged all of the above components except for the fuel tank pressure sensor and there is no change to the bus activity (monitoring with a back probe at the coolant pump).

Im assuming this LIN is connected to the DME If so go to the LIN at the DME an scope it there.

If its good you have what the looks like a high resistance in the LIN wire between the DME an the coolant pump.

Everything else functions correctly on the car correct If so then your problem is only between the DME and the coolant pump.

Plugged in or not.

He is getting sort of a square wave with the pump unplugged just not enough.

My bad. I was trying to understand the vote tab and thought; if I touch the arrows I would see a tag or comment.

Side note; Rocking out with my PP out: (PP is an initalism for Power Probe), is reference to the.

You have a subscriber of the DME M LIN dropping the voltage when the circuit is complete.

Just a quick analogy, Think of the LIN like any other single wire 12V MasterSlave (sub-bus) just like K bus.

The K bus had a splice comb that we would remove on linesubscriber at a time and see if the bus comes back up.

The above diagram suggests an internal connection between individual LIN bus circuits at the DME.

If after component disconnection the bus is still not restored to 12V you may.

Where did you find that diagram I have been looking at and AIR and can not find it.

If you follow the path in Jordans AD diagram he posted up, you can find the one he posted.

I havent come back in here to tidy up my statements and; as a group, temper our understanding of this subject.

I got off of a plane several hours ago and I just took some time to read, reflect and recoup, I have been sitting at the runway watching planes come and.

Bit Serial Data Interface Bmw X3 Series Cars Or

I have not worked on many F-series cars or any N20 motors.so I am just going to try and relay the BMW info I have available to me.

I think everyone here probably can help you with LIN bus better than I.

It seems there is at least a possibility of two cooling systems on this car.