Odd e39 tachometer problem!

[gordyshreds]

Tachometer and mpg gauge not working on my 1998 E39 520i. All other gauges and service indicator lights work fine. Any ideas? I have Removed cluster and checked connectors. Checked connectors to ECU. Did a cluster self test and everything inc the tachometer and mpg needes moved the full sweep. Help!?

[aka_kerrly]

I have a 97 BMW e39 and the only time the rev counter played a funny trick was when the crank position sensor had become undone/wobbly.

Are the clocks the original ones for the car? Don't the clocks need coding to the car on these or is it only the year 2000 onwards which appear to have quite different electrics to 96-98 cars.

Does yours have a OBD port under the steering wheel?

[gordyshreds]

Ive tried a doner set of clocks and they were the same. Its a 1998 model. Has obd2 port under the wheel. Its not the end of the world the tachometer not working but it is a niggle!

[E-bmw]

I another set of clocks are the same the problem is obviously the other end.

Have you tried using a code reader to check live data, revs should be in there.

[handpaper]

Unlock the OBC and see if it's getting tacho data?