Test M: The Position Cursor Is Inaccurate
PINPOINT TEST M: THE POSITION CURSOR IS INACCURATENormal Operation
The primary source of vehicle location for the navigation system is the audio control module (ACM) receiving the position signal through the global positioning system (GPS) antenna.
In addition, the ACM receives the wheel pulse signal from the instrument cluster (IC) (which gateways the signal from the ABS control module). This secondary signal is used to calculate vehicle position when the GPS signal is lost. It also supports the adaptive learning function of the ACM, whereby the ACM can compensate for long-term differences between the GPS signal location, and the distance traveled as calculated by the ABS wheel pulse distance traveled data.
- DTC B2204 (GPS Antenna Connection Open or Short) - sets when an open, short to ground, or short to voltage is detected in the GPS antenna circuit. If DTC B2204 is present, GO to Pinpoint Test J. Test J: No Global Positioning System (GPS) Antenna Signal
- DTC U2473 (Unexpected Vehicle Speed) - sets when the calculated vehicle distance traveled based on the wheel pulse signal does not agree with the GPS distances traveled information. To do this, the audio unit records the wheel pulse signal during a 4-second range, and compares it with the change in GPS location data. If the audio unit finds that the variation is greater than 0.5% after performing this check 4 times, it sets DTC U2473.
This pinpoint test is intended to diagnose the following:
- VSS signal concern
- ACM
