E36 DME Problem

[Triodeotl]

A few months ago my check engine light went on. I took my 94 M-Technic to my local BMW guy and he did a scan check on the car and the error message was that the O2 sensor had failed.

The O2 sensor was replaced but then we had a problem with the reading on the scan check off the port which indicated that the relay was bad. A day later the relay was replaced and everything read good as far as the range from rich to lean.

Two weeks ago the check engine light came on again. This time according to the scan check the car was running lean. The mechanic suspected that the DME box has a problem.

I got a used (same Bosch part # 0261 200413) DME used but when we hooked it up it (scan check) asked for the VIN # and also indicated something about the built in alarm on the car. Also with the new (used) DME the car would not start.

He suspects that this used DME is bad but the used parts dealer says that DME that he sent me needs to be reflashed by a BMW dealership. I did not know that a pre 96 DME needed to be reflashed.

We hooked up the original DME which does work and starts the car and the check engine light went off due to the fact that it had been unplugged. Yesterday the check engine light came on again.

Today I took the original DME out of the car after disconnecting the ground from the battery and also the relay as I wanted to see if the was water or something in it. No water and no flooding of its compartment. I got the DME apart according to the instructions on Pelicans site and I thought that I might try looking at the bottom of the DME board to solder flow any of the heavy connections.

Once I got the top cover off the DME I could not get the circuit board off of the bottom panel and I could not figure out why. It appears that the instructions on Pelican are not complete as to how to get the board off the bottom of the DME container.

Since I did not want to damage it I put it back together and reinstalled it in the same order that it was taken apart and put it back in the car. Car starts right off and the check engine light went off again.

I was told by Vertex that the rebuilt DME’s that they sell don’t have to be flashed over or anything. I am getting confused by all of this as the car runs fine with the original DME but I have no doubt that the check engine light will be on again in sometime.

Does anyone have any direct answers about this and what can be done to fix it? The car has 66,000 on it and it seems strange that it would be having a problem with the DME at that age. Or any ideas as to why the used DME does not work?