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 unit receiving the position signal through the global positioning system (GPS) antenna.
In addition, the audio unit receives the wheel pulse signal from the instrument cluster (which gateways the signal from the ABS 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 audio unit, whereby the audio unit can compensate for long-term differences between the GPS signal location, and the actual distance traveled by the vehicle.
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 U0155 (Lost Communication With Instrument Panel Cluster [IC] Control Module) - sets when the audio unit is missing messages from the instrument cluster for greater than 5 seconds.
DTC U2473 (Unexpected Vehicle Speed [VSS]) - sets when the calculated vehicle distance traveled based on the wheel pulse signal does not agree with the GPS antenna location. To do this, the audio unit compares the wheel pulse signal during a 4-second range, and compares it with the change in GPS antenna location. If the audio unit finds that the variation is greater than 0.5% after performing this check 4 times, it sets DTC U2473. When DTC U2473 is set, the adaptive learn function is disabled.
This pinpoint test is intended to diagnose the following:
- VSS signal concern
- Audio unit
