Navigation System - Shows Incorrect Vehicle Position
SI B 84 19 06Phone, Navigation Systems
August 2006
Technical Service
SUBJECT
Navigation System Shows Incorrect Vehicle Positioning
MODEL
E46 (3 Series Coupe) with option 609 (Navigation System and option 639 (TCU)
SITUATION
The Navigation system shows incorrect vehicle positioning or has no GPS signal.
CAUSE
GPS antenna signal interference/distortion caused by the Telematics Control Unit (TCU)
CORRECTION
In NAV Service Mode, check the GPS reception signals (S/N value) of the visible satellites in a known good area and compare the result with a known good vehicle.
How to enter the NAV Service Mode:
^ Switch on the Board Monitor
^ Press the "MENU" button
^ Select "Settings"
^ In "Settings", press and hold the "MENU" button for approx. 8 seconds
^ Select "GPS"
^ Press "Function"
^ Press "GPS - Tracking Function"
If the displayed S/N value is 4 or less, pull fuse # 39 (behind the glove box) to disconnect the TCU and recheck the S/N value.
^ If the displayed S/N value stays at 4 or less, troubleshoot the Navigation system and the GPS antenna
^ If the S/N value increases significantly (10 or higher) on the majority of the visible satellites, install a separate GPS antenna in the area behind the instrument cluster (same as on E46 Convertible)
PROCEDURE
1. Remove the instrument cluster, refer to RA 62 21000 (Removing and installing complete instrument cluster).
2. Remove the trim panel for the pedal assembly, refer to repair instruction RA 51 45 185 (Removing and installing/replacing trim for pedal assembly).
3. Remove the side trim panel on the A-pillar, refer to repair instruction RA 51 43 070 (Removing and installing/replacing side trim panel, footwell, on A-pillar, left).
4. Remove the entrance cover strip on the driver side, refer to repair instruction RA 51 47 000 (Removing and installing/replacing front left or right entrance cover strip).
5. Remove the rear seat, refer to repair instruction RA 52 26 005 (Removing and installing/replacing rear seat).
6. Remove the trim on the rear seat backrest (driver side), refer to repair instruction RA 51 43 (Removing and installing/replacing trim on rear seat backrest side section).
7. Remove the side section of the rear seat (driver side), refer to repair instruction RA 52 26 008 (Removing and installing/replacing left or right side section of rear seat backrest).
8. Remove the left rear light (bulb holder, driver side).
9. Remove the trunk floor mat and the left trunk trim, refer to repair instruction RA 51 47 151 (Removing and installing/replacing trunk wheel housing trim, left).
10. Remove the Navigation computer, refer to repair instruction RA 65 90 510 (Removing and installing/replacing navigation computer).
11. Disconnect the original GPS antenna cable (2) from the Navigation computer and tie it back to the wiring harness. Cover the cable and the connector with a tape (1).
12. Mount the GPS antenna to the plastic bracket in the area behind the instrument cluster (above the air duct).
13. Connect the end of the GPS antenna cable (1) to the coax extension cable (2), fix it to the body (with a tape) and run it down along the A-pillar on the existing wiring harness. Make sure that the coax extension cable doesn't get damaged when re-installing the instrument cluster.
14. Run the coax extension cable (2) along the left side of the body all the way back into to trunk area to the Navigation system and tie it to the existing wiring harness (1).
15. Connect the coax extension cable to the Navigation system (1) and tape it to the existing wiring harness.
16. Re-install all interior parts in the opposite order they got removed, make sure that the cables do not get damaged.
17. Re-install the instrument cluster.
18. Re-install the Navigation computer.
19. Test the Navigation system for proper function and re-check the GPS reception signals of the visible satellites in a known good area (refer to the procedure described in Correction).
PARTS INFORMATION
WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle Limited Warranty.
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