I've had the same problems and unplugged my tach today. Seems much better but only time will tell. How is the tach sensitive to water though? I'm guessing a confused tach is interrupting the CanBus communication that causes the other communication problems but how is water affecting anything?

Peter

 

Thank you all for posting. I have an 06 that is doing the same and was having a hard time finding any information on the problem. Lots of really helpful information here. Thanks again. I will post my solution, once I have it!

 

I drove without the tachometer for two months and the car was great. I bought a second (used) tachometer and installed it and it is still doing great.

The nicest thing about this is that it fixed the car. The second nicest thing was that the test was free.

Regards,
Peter

 

The problem is that something goes awry in the tachometer. A short, or something in the circuit board fails causing a signal to be sent from the tachometer back into the canbus. The Tachometer is supposed to only receive data, and not be transmitting anything. My assumption is that its a small electrical pulse. This pulse is received by the rest of the CANBUS receivers. They don't know how to interpret the pulse so have a momentary freak out.

My independent Mini mechanic in San Diego at the time had no clue. So I finally talked him into taking the tach off a parts car he had and putting it on mine to prove or disprove the theory. As others have attested, this did indeed fix the problem.

One caveat, for the 06 R53, the Tachometer had to be paired with the vehicle with the service computer. I'm not sure of the why of that or if its different for an 05.

But happy to report that almost 4 years later the problem has not resurfaced.

 

I have an 04 MCS that has been sitting for about 6 months. The battery was dead so I put in a new one, and started it up. It ran fine but no gauges at all. Nothing seems to make them work. I pulled the speedo out and checked all the cables, nothing. Here is the weird part, when I plugged in my Peake R5 OBDII reader, the tach and speedo came to life. As soon as I unplugged it, they went dark. I get the dreaded P1612 code which is a comm issue to the instrument cluster. I checked all the fuses in the cabin and they are good. So what is the deal with the OBDII reader port that makes the gauges work??

04 MCS, 6spd, 120K miles
Slick top, original alternator

 

Might start a new thread with the problem description.

Caveat: I have no actual expertise in this diagnosis. Wonder if there is a slightly loose wire at the obd? and plugging in is making contact. Or the obd reader is bridging two wires when you plug it in that should be connected elsewhere but have degraded? This could also be the OBD putting enough resistance on the line to correct a voltage level that is being caused by wire degradation that the instrument cluster now sees it in tolerance and wakes up.

None of which is helpful in getting you closer to the fix. I have noticed an alarming about of plastic degradation on my 06 in the last year.

 

I had a similar issue.It was a problem with a corroded wire.

 

My 07 R52 is doing the same thing. It's been driving me crazy trying to figure out the cause. I will unhook the Tach and see if my problems go away and replace it if they do.
Thanks,

 

Had the same issue just yesterday. Disconnected the IPOD crap from the radio and it cleared up.