Radio - FM Band Static Noise

Group 65
Radio and Accessories



Bulletin Number
65 23 92 (3712)



Woodcliff Lake, NJ
January 1991
Product Engineering



SUBJECT:
FM Radio Interference from Cellular Telephone

MODELS:
E36

Situation:
We have received a few reports of the BMW Cellular telephone increasing the background noise level (static) of a distant or weak FM radio signal when the phone is powered "ON." This occurs only on E36 vehicles, and most often with two-door versions.

Correction:
If a customer complaint is received, obtain a ferrite ring (P/N 99 99 9 737 826). Install the part according to the instructions below. Note that the wire loops must be fairly tight against the ring to be effective. The ferrite ring acts like a choke, and reduces the stray signals causing interference with the FM tuner section of the vehicle radio.

Procedure:
INSTALLATION OF EMI SUPPRESSION RING

In order to minimize electro-magnetic interference, the ferrite ring from the installation kit (P/N 99 99 9 737 826) must be installed on the ribbon data cable at the cable end that plugs into the transceiver.





1. See Figure. Starting with the ring positioned approximately 6" from the end of the data cable, turn 2 coils of data cable tightly through and around the ferrite ring.



2. Plug data cable into transceiver.

3. Secure ferrite ring to antenna coax cable with the wire-tie so that mass of ring does not swing freely or pull on data cable connector.



Parts
Information:
Description Part Number
Ferrite Ring 99 99 9 737 826

Note:
The ferrite ring will also be included in the new E36 telephone installation kits, as well as the E36 cable kit. Every ferrite ring is packaged with installation instructions.

Warranty
Status:
Part and labor reimbursable under the terms of the applicable BMW New Car Limited Warranty.

Defect Code: 65 31 00 12 AZ
Labor Operation: 65 10 009 Troubleshooting Radio
Labor Allowance: 3 FRU