Electrical Compass System Description - Overview

Overview 

The electrical compass sends the azimuth (direction) information in the 8-directions (N, NE, E, SE, S, SW, W, NW) to the center display unit via the audio unit.

Starting Operation 

When the vehicle is turned to the ON mode, the electrical compass unit communicates with the audio unit, and the self-test mode begins automatically.

The self-test function checks for the current voltage, the non-volatile memory (NVM), and the ROM status in the electrical compass unit. If the unit detects a malfunction while in the self-test, it indicates a malfunction by flashing the compass information segments (CAL and NW) in the center display unit.

Basic Operation 

The electrical compass unit uses the noise filter to the raw magnetic data. The noise filter on/off depends on the intensity of environment magnetic noise. In the filter mode, the calculation may be delay several seconds. After processing the compass data, the unit send the azimuth (direction) information to the audio unit.

The electrical compass unit also receives following signals via the audio unit:

• The electrical compass unit receive the vehicle speed information from the gauge control module via the audio unit. The azimuth information is fixed while parked.
• The electrical compass unit receive the RR DEF on/off information from the climate control unit. The electrical compass unit compensates for magnetic anomalies when the rear window defogger is on.

Self-Calibration 

The electrical compass unit has a self-calibration function. It detects and compensates for magnetic anomalies caused by bridges, subways and large steel structures. When the vehicle leaves an area with a strong magnetic interference field (2, 400 mG or more), the electrical compass unit automatically begins calibrating. If needed, you can manually calibrate the compass.

Zone Selection 

Zone selection is required to compensate for the difference between magnetic North and geographic North. This deviation is referred to as declination, the compass compensates for declination when you select the zone where the vehicle is located.