23
24
−
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Yaw Rate Tuning
Tire Calibrate
23-130
Navigation System
System Diagnostic Mode (cont’d)
Return
Set
Reset
CCW
CW
Tuning
0.0%
ANG-Disp
0°
Tire
Calibrate
Return
Auto Tuning
OFF
Level0
xx.xx%
Set
Study
Tire
Cal. Tuning
ON
OFF
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 healthy, the
random changes in these two voltage 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’’ or ‘‘CW’’, or ‘‘Set’’ buttons.
These are used for factory setup only.
For gross problems with the sensor, the stationary test
usually confirms whether the sensor is defective. For
yaw rate issues related to driving, do 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 control 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 control unit’s yaw sensor is
defective. You can touch ‘‘Reset’’ to clear ‘‘ANG-
Disp’’, and dotted line.
3. If either test fails, please enter ‘‘Yaw rate sensor
defective’’ for the problem description, on the
‘‘Navigation core return form’’.
As the vehicle moves, the navigation system receives
speed pulses from the PCM. These pulses are
converted using a conversion factor to a mph speed
that moves the vehicle position (VP) on the map. The
navigation system has an internal tuning function that
generates and refines this factor based on actual
driving. The ‘‘Level’’ indicates the status of the tuning.
At navigation initialization, it begins at 0, and increases
to 10 as the navigation system is used.
• The ‘‘Auto Tuning’’ is factory set to ‘‘ON’’, and should
remain on.
• The ‘‘Study’’ indicates the tuning status. If it is less
than 10, the unit is still calibrating.
• The ‘‘Tire-Cal. Tuning’’ and ‘‘Set’’ should not be used.
It is for factory use only.