Service Interval Indicator - Prevent Unnecessary R and R
85BMW10GROUP 62 Instruments
Bulletin Number 62 05 85 (1075)
Page 1 of 2
Montvale, NJ July 1985 Technical Dept.
SUBJECT: Service Interval Indicator (S.I.I.)
MODELS: All so equipped
Situation: Many S.I.I. printed circuit boards are replaced when there is no defect in that component.
Listed are the two common symptoms which are seen.
Symptom #1: The green lights go out too fast (every 175-200 miles) even after an inspection reset.
Information: For one rotation of the rear wheels, the rear axle impulse generator sends out 9 pulses. This is then de-coded down to one pulse for every wheel rotation for the S.I.I. This is performed by a different component on the various models. If this pulse fails to be de-coded, the S.I.I. will relieve 9 times the proper amount of pulses.
Correction
#1: E30 - Replace the fuel economy gauge. This is the decoding device for these
models.
E28, E24, E23 - Replace the speedometer. This is the decoding device for these models.
Symptom #2: The 1 yellow LED, the 3 red LED's and the oil service light suddenly came on all at the same time. This can indicate that the NI-CAD buffer batteries have discharged. This could be for many reasons:
1. New car - buffer batteries not fully charged from the factory.
2. Fuses missing - no power to the S.I.I. circuit board.
3. Replacement board from parts stock - buffer batteries not fully charged.
4. Defective S.I.I. board.
After finding the fault for the discharged batteries, resetting with special tool P/N 88 88 6 621 100 can be performed. Follow the instructions on attachment for resetting or the batteries may again become discharged.