The indicator can be reset at any time, for example after the next maintenance. To do this, you can use the BMW indicator reset device or a homemade jumper.
Resetting the indicator readings using a jumper (cars produced before December 1985.)
Please note: Since January 1986, a 20-pin diagnostic connector has been installed, so a BMW adapter - 621140 is required for resetting. If desired, the indicator readings can be reset at a BMW service station free of charge.
To reset the indicator on cars produced before December 1985, you need the plug of the engine diagnostic connector. BMW 1252 1286052.
The contacts are numbered on the inside of the plug. Drill out contacts 1 and 7 of the plug with a 5 mm drill.
Use a 4 mm² copper wire as a jumper. Bend the ends of the jumper with pliers.
Remove the plug installed on the diagnostic connector. In this case, you need to release the clamps with a small screwdriver.
Replace the standard plug with a drilled plug.
Turn on the ignition. Do not start the engine.
Insert the jumper first into contact 1 (ground). This contact is located in the middle of the connector.
Caution: Make sure the contact is secure. Intermittent contact may damage the electrical equipment.
Insert the other end of the jumper into contact 8 7. To reset the oil change interval, leave the jumper connected for 3 seconds. The time should be measured with a stopwatch.
To reset the maintenance intervals, set the jumper to 12 seconds. In this case, first insert it into contact 1, then the other end into contact 7 and note the time using a stopwatch.
Note: Vehicles manufactured since January 1986 have an additional annual technical inspection indicator in the form of a clock symbol. This indicator can be reset in the same way as the service interval indicator, but there must be a pause of at least 10 seconds between resetting the indicators.
Information taken from this resource «www.bmwman.ru»