Symptom Related Diagnostic Procedures

EMC Measures E61 And E91

Measures to increase electromagnetic compatibility
For certain known fault profiles, design measures have already been implemented in production.
Check these design measures in the event of EMC faults:
1. Earth strap on the luggage compartment lid
Fault profile with effect:
corrosion means that the earth connection between the luggage compartment lid and body is lost.
This means that the luggage compartment lid oscillates and is electrically undefined.
The reception deteriorates 2 to 3 years after production of the vehicle.
2. Suppressor filter for the additional brake light
Fault profile with effect:
in the wiring harness, EMC faults occur between the additional brake light, including supply lead, and the AM aerial.
The reception deteriorates on braking.
3. Cable choke
Fault profile with effect:
the cable choke sets the screen of the coaxial line between the head unit and aerial diversity to earth.
In areas with poor transmission power, AM reception is disrupted or is lost at an earlier stage.

EMC measures E61:







EMC measures E91:







Notes for Service department

Diagnosis instructions

The aerial diagnosis runs as follows:
The self-diagnosis of the aerial diversity is triggered in the test module of the BMW diagnosis system. The self-diagnosis includes a check of the aerial inputs on the basis of a current measurement (direct current). If a fault is found, the aerial diagnosis aborts after the self-diagnosis.
If the self-diagnosis has a positive result, the FM aerials are specifically activated and evaluated with regard to field strength (check of the aerials).
Diagram of aerial diagnosis:







Subject to change.