[Paid Software Announcement and Discussion] JohnnyCanuck:
There is no intent or shortcut within AA for starting or stopping the server. There is a shortcut that Tasker can use to open the AA settings page. From there you can use Autoinput to have Tasker simulate the button presses necessary.

Tasker code below (save as *.tsk.xml and then import into Tasker), but you have to have buy Autoinput from Autoapps to make this work.

<TaskerData sr="" dvi="1" tv="5.9.1">
<Task sr="task6">
<cdate>1575996528919</cdate>
<edate>1579017829374</edate>
<id>6</id>
<nme>AAServer</nme>
<pri>100</pri>
<Kid sr="Kid">
<eperm0>SYSTEM_ALERT_WINDOW</eperm0>
<launchID>2</launchID>
<pkg>com.aaserver.start</pkg>
<vTarg>28</vTarg>
<vnme>2.0</vnme>
<vnum>13</vnum>
</Kid>
<Share sr="Share">
<d>HUS Start</d>
<p>false</p>
<t></t>
</Share>
<Action sr="act0" ve="7">
<code>20</code>
<App sr="arg0">
<appClass>com.google.android.projection.gearhead.companion.settings.DefaultSettingsActivity</appClass>
<appPkg>com.google.android.projection.gearhead</appPkg>
<label>Android Auto:Settings</label>
</App>
<Str sr="arg1" ve="3"/>
<Int sr="arg2" val="0"/>
<Int sr="arg3" val="0"/>
</Action>
<Action sr="act1" ve="7">
<code>30</code>
<Int sr="arg0" val="0"/>
<Int sr="arg1" val="4"/>
<Int sr="arg2" val="0"/>
<Int sr="arg3" val="0"/>
<Int sr="arg4" val="0"/>
</Action>
<Action sr="act2" ve="7">
<code>1732635924</code>
<Bundle sr="arg0">
<Vals sr="val">
<ActionId>More options</ActionId>
<ActionId-type>java.lang.String</ActionId-type>
<ActionType>16</ActionType>
<ActionType-type>java.lang.String</ActionType-type>
<EnableDisableAccessibilityService><null></EnableDisableAccessibilityService>
<EnableDisableAccessibilityService-type>java.lang.String</EnableDisableAccessibilityService-type>
<FieldSelectionType>0</FieldSelectionType>
<FieldSelectionType-type>java.lang.String</FieldSelectionType-type>
<IsFirstAction>false</IsFirstAction>
<IsFirstAction-type>java.lang.Boolean</IsFirstAction-type>
<IsTaskerAction>false</IsTaskerAction>
<IsTaskerAction-type>java.lang.Boolean</IsTaskerAction-type>
<NearbyText><null></NearbyText>
<NearbyText-type>java.lang.String</NearbyText-type>
<Password><null></Password>
<Password-type>java.lang.String</Password-type>
<RepeatInterval><null></RepeatInterval>
<RepeatInterval-type>java.lang.String</RepeatInterval-type>
<RepeatTimes><null></RepeatTimes>
<RepeatTimes-type>java.lang.String</RepeatTimes-type>
<StoredAction><null></StoredAction>
<StoredAction-type>java.lang.String</StoredAction-type>
<TextToWrite><null></TextToWrite>
<TextToWrite-type>java.lang.String</TextToWrite-type>
<com.twofortyfouram.locale.intent.extra.BLURB>Type: Text
Value: More options
Action : Click</com.twofortyfouram.locale.intent.extra.BLURB>
<com.twofortyfouram.locale.intent.extra.BLURB-type>java.lang.String</com.twofortyfouram.locale.intent.extra.BLURB-type>
<net.dinglisch.android.tasker.RELEVANT_VARIABLES><StringArray sr=""><_array_net.dinglisch.android.tasker.RELEVANT_VARIABLES0>%err
Error Code
Only available if you select &lt;b&gt;Continue Task After Error&lt;/b&gt; and the action ends in error</_array_net.dinglisch.android.tasker.RELEVANT_VARIABLES0><_array_net.dinglisch.android.tasker.RELEVANT_VARIABLES1>%errmsg
Error Message
Only available if you select &lt;b&gt;Continue Task After Error&lt;/b&gt; and the action ends in error</_array_net.dinglisch.android.tasker.RELEVANT_VARIABLES1></StringArray></net.dinglisch.android.tasker.RELEVANT_VARIABLES>
<net.dinglisch.android.tasker.RELEVANT_VARIABLES-type>[Ljava.lang.String;</net.dinglisch.android.tasker.RELEVANT_VARIABLES-type>
<net.dinglisch.android.tasker.extras.VARIABLE_REPLACE_KEYS>ActionId FieldSelectionType ActionType plugininstanceid plugintypeid </net.dinglisch.android.tasker.extras.VARIABLE_REPLACE_KEYS>
<net.dinglisch.android.tasker.extras.VARIABLE_REPLACE_KEYS-type>java.lang.String</net.dinglisch.android.tasker.extras.VARIABLE_REPLACE_KEYS-type>
<net.dinglisch.android.tasker.subbundled>true</net.dinglisch.android.tasker.subbundled>
<net.dinglisch.android.tasker.subbundled-type>java.lang.Boolean</net.dinglisch.android.tasker.subbundled-type>
<plugininstanceid>2aefa831-e13c-45db-a664-6e644b76bb41</plugininstanceid>
<plugininstanceid-type>java.lang.String</plugininstanceid-type>
<plugintypeid>com.joaomgcd.autoinput.intent.IntentPerformAction</plugintypeid>
<plugintypeid-type>java.lang.String</plugintypeid-type>
</Vals>
</Bundle>
<Str sr="arg1" ve="3">com.joaomgcd.autoinput</Str>
<Str sr="arg2" ve="3">com.joaomgcd.autoinput.activity.ActivityConfigPerformAction</Str>
<Int sr="arg3" val="23"/>
</Action>
<Action sr="act3" ve="7">
<code>30</code>
<Int sr="arg0" val="0"/>
<Int sr="arg1" val="2"/>
<Int sr="arg2" val="0"/>
<Int sr="arg3" val="0"/>
<Int sr="arg4" val="0"/>
</Action>
<Action sr="act4" ve="7">
<code>1732635924</code>
<Bundle sr="arg0">
<Vals sr="val">
<ActionId>Start head unit server</ActionId>
<ActionId-type>java.lang.String</ActionId-type>
<ActionType>16</ActionType>
<ActionType-type>java.lang.String</ActionType-type>
<EnableDisableAccessibilityService><null></EnableDisableAccessibilityService>
<EnableDisableAccessibilityService-type>java.lang.String</EnableDisableAccessibilityService-type>
<FieldSelectionType>0</FieldSelectionType>
<FieldSelectionType-type>java.lang.String</FieldSelectionType-type>
<IsFirstAction>false</IsFirstAction>
<IsFirstAction-type>java.lang.Boolean</IsFirstAction-type>
<IsTaskerAction>false</IsTaskerAction>
<IsTaskerAction-type>java.lang.Boolean</IsTaskerAction-type>
<NearbyText><null></NearbyText>
<NearbyText-type>java.lang.String</NearbyText-type>
<Password><null></Password>
<Password-type>java.lang.String</Password-type>
<RepeatInterval><null></RepeatInterval>
<RepeatInterval-type>java.lang.String</RepeatInterval-type>
<RepeatTimes><null></RepeatTimes>
<RepeatTimes-type>java.lang.String</RepeatTimes-type>
<StoredAction><null></StoredAction>
<StoredAction-type>java.lang.String</StoredAction-type>
<TextToWrite><null></TextToWrite>
<TextToWrite-type>java.lang.String</TextToWrite-type>
<com.twofortyfouram.locale.intent.extra.BLURB>Type: Text
Value: Start head unit server
Action : Click</com.twofortyfouram.locale.intent.extra.BLURB>
<com.twofortyfouram.locale.intent.extra.BLURB-type>java.lang.String</com.twofortyfouram.locale.intent.extra.BLURB-type>
<net.dinglisch.android.tasker.RELEVANT_VARIABLES><StringArray sr=""><_array_net.dinglisch.android.tasker.RELEVANT_VARIABLES0>%err
Error Code
Only available if you select &lt;b&gt;Continue Task After Error&lt;/b&gt; and the action ends in error</_array_net.dinglisch.android.tasker.RELEVANT_VARIABLES0><_array_net.dinglisch.android.tasker.RELEVANT_VARIABLES1>%errmsg
Error Message
Only available if you select &lt;b&gt;Continue Task After Error&lt;/b&gt; and the action ends in error</_array_net.dinglisch.android.tasker.RELEVANT_VARIABLES1></StringArray></net.dinglisch.android.tasker.RELEVANT_VARIABLES>
<net.dinglisch.android.tasker.RELEVANT_VARIABLES-type>[Ljava.lang.String;</net.dinglisch.android.tasker.RELEVANT_VARIABLES-type>
<net.dinglisch.android.tasker.extras.VARIABLE_REPLACE_KEYS>ActionId FieldSelectionType ActionType plugininstanceid plugintypeid </net.dinglisch.android.tasker.extras.VARIABLE_REPLACE_KEYS>
<net.dinglisch.android.tasker.extras.VARIABLE_REPLACE_KEYS-type>java.lang.String</net.dinglisch.android.tasker.extras.VARIABLE_REPLACE_KEYS-type>
<net.dinglisch.android.tasker.subbundled>true</net.dinglisch.android.tasker.subbundled>
<net.dinglisch.android.tasker.subbundled-type>java.lang.Boolean</net.dinglisch.android.tasker.subbundled-type>
<plugininstanceid>a6d62208-fb22-4ff6-8f15-f49a13eb6db9</plugininstanceid>
<plugininstanceid-type>java.lang.String</plugininstanceid-type>
<plugintypeid>com.joaomgcd.autoinput.intent.IntentPerformAction</plugintypeid>
<plugintypeid-type>java.lang.String</plugintypeid-type>
</Vals>
</Bundle>
<Str sr="arg1" ve="3">com.joaomgcd.autoinput</Str>
<Str sr="arg2" ve="3">com.joaomgcd.autoinput.activity.ActivityConfigPerformAction</Str>
<Int sr="arg3" val="23"/>
</Action>
<Action sr="act5" ve="7">
<code>30</code>
<Int sr="arg0" val="0"/>
<Int sr="arg1" val="1"/>
<Int sr="arg2" val="0"/>
<Int sr="arg3" val="0"/>
<Int sr="arg4" val="0"/>
</Action>
<Action sr="act6" ve="7">
<code>25</code>
<Int sr="arg0" val="0"/>
</Action>
<Img sr="icn" ve="2">
<uri>content://com.android.providers.media.documents/document/image%3A42</uri>
</Img>
</Task>
</TaskerData>