Yaw Rate
Yaw RateThis diagnostic checks the yaw rate sensor in the control unit. This device detects when the vehicle turns, and repositions the vehicle position icon on the map screen. For more detailed information, see the yaw rate sensor theory of operation under "System Description".
- "Sensor" indicates the voltage output from the yaw rate sensor. It should indicate about 2.500 V when stopped.
- "Offset" is the reference voltage or standard within the yaw rate sensor. It also should indicate about 2.500 V when stopped.
- A "sensor" output voltage LOWER than the "Offset" voltage indicates that the vehicle is turning to the right.
A "sensor" output voltage HIGHER than the "Offset" voltage indicates that the vehicle is turning to the left.
- The yaw rate offset, and sensor should both indicate about 2.500 V when stopped. If either reads zero, or 5.000 V, replace the navigation unit.
- The yaw rate offset and sensor should be within +/- 0.01 V of each other when stopped. The sensor value should change relative to the offset as the car is turned while driving. If not, replace the navigation unit.
Example: Car stopped
Normal
Offset 2.526 V
Sensor 2.516-2.536 V
Abnormal
Offset 2.526 V
Sensor 2.623 V
Example: Car turning
Normal
Offset 2.526 V
Sensor 2.678 V (left turn), 2.478 V (right turn)
Abnormal
Offset 2.526 V
Sensor 2.623 V (no change on turns)
The settings "CCW Cal Factor", "CW Cal Factor", and "Set" are for factory use only. THIS SHOULD NEVER BE ADJUSTED.
Touch "Tuning" to view small but gradual yaw rate problems.
Yaw Rate Tuning
This diagnostic allows you to graphically display problems with the yaw rate sensor.
- The "ANG-Disp" value accumulates any differences between the "offset," and "sensor" voltages (see Yaw Rate diagnostic). When the sensor is normal, the random changes in these two voltages generally cancels out, so the value is 0. However if one voltage is consistently higher than the other, then the "ANG-Disp" value accumulates the constant change.
- The "Reset" button temporarily clears the angular accumulation (ANG-Disp), and clears the display dots.
- Do not touch the "CCW," "CW," or "Set" buttons. These are used for factory setup only.
Two tests are explained below. For gross problems with the sensor, the stationary test usually confirms whether the sensor is defective. For yaw rate issues related to driving, perform the road test described below.
1. Stationary test: If the "VP" icon spins in place and the "ANG-Disp" value slowly increases or decreases in value, the yaw rate sensor is defective. Replace the navigation unit.
2. Road test: Drive the vehicle on a very straight road. Enter the diagnostic mode, select "Yaw rate," and touch the "Tuning" button. While driving down a straight road, the white "dots" should trace a straight line across the screen. However, if you are driving on a straight road, and you notice the dots constantly dropping down or heading up as you drive, the navigation unit's yaw sensor is defective. You can touch "Reset" to clear "ANG-Disp," and dotted lines.
If either test above fails, please enter "Yaw rate sensor defective" for the problem description, on the "Navigation core return form."
