[Nexus 7 (2013) Android Development] a8ksh4:
Okay, here's a logcat of what happens during android auto failed startup...

foo

01-05 12:36:46.426 499 523 I ActivityManager: Displayed android/com.android.internal.app.ChooserActivity: +351ms

01-05 12:36:49.038 688 712 E RecentsTaskLoader: Unexpected null component name or activity info: ComponentInfo{me.twrp.twrpapp/me.twrp.officialtwrpapp.MainActivity}, null

01-05 12:36:51.226 499 1102 I ActivityManager: START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.google.android.projection.gearhead/com.google.android.gearhead.vanagon.VnLaunchPadActivity bnds=[408,1380][600,1572] (has extras)} from uid 10013

01-05 12:36:49.038 688 712 I chatty : uid=10023(com.android.systemui) Binder:688_2 identical 1 line

01-05 12:36:49.039 688 712 E RecentsTaskLoader: Unexpected null component name or activity info: ComponentInfo{me.twrp.twrpapp/me.twrp.officialtwrpapp.MainActivity}, null

01-05 12:36:51.229 267 1612 D ACDB-LOADER: ACDB -> send_afe_cal

01-05 12:36:51.229 267 1612 D audio_hw_primary: enable_snd_device: snd_device(2: speaker)

01-05 12:36:51.229 267 1612 D audio_route: Apply path: speaker

01-05 12:36:51.238 267 1612 D audio_hw_primary: enable_audio_route: usecase(1) apply and update mixer path: low-latency-playback

01-05 12:36:51.238 267 1612 D audio_route: Apply path: low-latency-playback

01-05 12:36:51.300 267 1612 D audio_hw_primary: out_write: retry previous failed cal level set

01-05 12:36:51.385 3254 3326 W Adreno-EGL: <qeglDrvAPI_eglGetConfigAttrib:607>: EGL_BAD_ATTRIBUTE

01-05 12:36:51.391 688 1814 E RecentsTaskLoader: Unexpected null component name or activity info: ComponentInfo{me.twrp.twrpapp/me.twrp.officialtwrpapp.MainActivity}, null

01-05 12:36:51.392 688 1814 I chatty : uid=10023(com.android.systemui) Binder:688_5 identical 1 line

01-05 12:36:51.393 688 1814 E RecentsTaskLoader: Unexpected null component name or activity info: ComponentInfo{me.twrp.twrpapp/me.twrp.officialtwrpapp.MainActivity}, null

01-05 12:36:51.437 3254 3326 D vndksupport: Loading /vendor/lib/hw/gralloc.msm8960.so from current namespace instead of sphal namespace.

01-05 12:36:51.480 499 523 I ActivityManager: Displayed com.google.android.projection.gearhead/com.google.android.gearhead.vanagon.VnLaunchPadActivity: +202ms

01-05 12:36:51.588 3254 3254 I GH.LifetimeManager: connectToCarService

01-05 12:36:51.588 3254 3254 E GH.LifetimeManager: CarService onConnectionFailed (API_UNAVAILABLE: null)

01-05 12:36:51.628 499 1719 W ActivityManager: Unable to start service Intent { act=com.google.android.gms.car.service.START pkg=com.google.android.gms } U=0: not found

01-05 12:36:51.629 499 510 W ActivityManager: Unbind failed: could not find connection for android.os.BinderProxy@d53e446

01-05 12:36:51.629 3254 3621 E GmsClient: unable to connect to service: com.google.android.gms.car.service.START on com.google.android.gms

01-05 12:36:51.632 252 252 D SurfaceFlinger: duplicate layer name: changing com.google.android.projection.gearhead/com.google.android.gearhead.vanagon.VnLaunchPadActivity to com.google.android.projection.gearhead/com.google.android.gearhead.vanagon.VnLaunchPadActivity#1

01-05 12:36:51.660 3254 3326 W Adreno-EGL: <qeglDrvAPI_eglGetConfigAttrib:607>: EGL_BAD_ATTRIBUTE

01-05 12:36:51.678 3254 3326 D vndksupport: Loading /vendor/lib/hw/gralloc.msm8960.so from current namespace instead of sphal namespace.

01-05 12:36:51.679 3254 3254 W GH.CarApiClientManager: connection failed: ConnectionResult{statusCode=API_UNAVAILABLE, resolution=null, message=null}

01-05 12:36:51.679 3254 3254 E GH.LifetimeManager: CarService onConnectionFailed (API_UNAVAILABLE: null)

01-05 12:36:51.733 252 252 D SurfaceFlinger: duplicate layer name: changing com.google.android.projection.gearhead/com.google.android.gearhead.vanagon.VnLaunchPadActivity to com.google.android.projection.gearhead/com.google.android.gearhead.vanagon.VnLaunchPadActivity#2

01-05 12:36:51.765 3254 3326 W Adreno-EGL: <qeglDrvAPI_eglGetConfigAttrib:607>: EGL_BAD_ATTRIBUTE

01-05 12:36:51.783 3254 3326 D vndksupport: Loading /vendor/lib/hw/gralloc.msm8960.so from current namespace instead of sphal namespace.

01-05 12:36:52.933 1104 1215 W Adreno-EGL: <qeglDrvAPI_eglGetConfigAttrib:607>: EGL_BAD_ATTRIBUTE

01-05 12:36:52.959 688 1816 E RecentsTaskLoader: Unexpected null component name or activity info: ComponentInfo{me.twrp.twrpapp/me.twrp.officialtwrpapp.MainActivity}, null

01-05 12:36:52.966 688 1816 I chatty : uid=10023(com.android.systemui) Binder:688_6 identical 1 line

01-05 12:36:52.966 688 1816 E RecentsTaskLoader: Unexpected null component name or activity info: ComponentInfo{me.twrp.twrpapp/me.twrp.officialtwrpapp.MainActivity}, null

01-05 12:36:52.974 1104 1215 D vndksupport: Loading /vendor/lib/hw/gralloc.msm8960.so from current namespace instead of sphal namespace.

01-05 12:36:53.317 3254 3254 E WindowManager:

01-05 12:36:53.317 3254 3254 E WindowManager: android.view.WindowLeaked: Activity com.google.android.gearhead.vanagon.VnLaunchPadActivity has leaked window DecorView@7a2c116[] that was originally added here

01-05 12:36:53.317 3254 3254 E WindowManager:	at android.view.ViewRootImpl.<init>(ViewRootImpl.java:485)

01-05 12:36:53.317 3254 3254 E WindowManager:	at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:346)

01-05 12:36:53.317 3254 3254 E WindowManager:	at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:93)

01-05 12:36:53.317 3254 3254 E WindowManager:	at android.app.Dialog.show(Dialog.java:330)

01-05 12:36:53.317 3254 3254 E WindowManager:	at dim.c(SourceFile:28)

01-05 12:36:53.317 3254 3254 E WindowManager:	at bid.b(SourceFile:405)

01-05 12:36:53.317 3254 3254 E WindowManager:	at bid.a(SourceFile:434)

01-05 12:36:53.317 3254 3254 E WindowManager:	at big.a(SourceFile:31)

01-05 12:36:53.317 3254 3254 E WindowManager:	at bau.a(SourceFile:35)

01-05 12:36:53.317 3254 3254 E WindowManager:	at bid.sY(SourceFile:14)

01-05 12:36:53.317 3254 3254 E WindowManager:	at com.google.android.gearhead.vanagon.VnLaunchPadActivity.JP(SourceFile:101)

01-05 12:36:53.317 3254 3254 E WindowManager:	at dil.run(Unknown Source:2)

01-05 12:36:53.317 3254 3254 E WindowManager:	at android.os.Handler.handleCallback(Handler.java:790)

01-05 12:36:53.317 3254 3254 E WindowManager:	at android.os.Handler.dispatchMessage(Handler.java:99)

01-05 12:36:53.317 3254 3254 E WindowManager:	at android.os.Looper.loop(Looper.java:164)

01-05 12:36:53.317 3254 3254 E WindowManager:	at android.app.ActivityThread.main(ActivityThread.java:6494)

01-05 12:36:53.317 3254 3254 E WindowManager:	at java.lang.reflect.Method.invoke(Native Method)

01-05 12:36:53.317 3254 3254 E WindowManager:	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)

01-05 12:36:53.317 3254 3254 E WindowManager:	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

01-05 12:36:53.521 1104 1215 W OpenGLRenderer: Incorrectly called buildLayer on View: ShortcutAndWidgetContainer, destroying layer...

01-05 12:36:53.521 1104 1215 W OpenGLRenderer: Incorrectly called buildLayer on View: ShortcutAndWidgetContainer, destroying layer...

01-05 12:36:53.606 499 1913 I OpenGLRenderer: Initialized EGL, version 1.4

01-05 12:36:53.607 499 1913 D OpenGLRenderer: Swap behavior 1

01-05 12:36:53.611 499 1913 W Adreno-EGL: <qeglDrvAPI_eglGetConfigAttrib:607>: EGL_BAD_ATTRIBUTE

These are the most interesting bits:

EDIT: I was able to fix this by reloading with an older version of open gapps. I used the pico package from here:

https://github.com/opengapps/arm/releases/tag/20180910

https://github.com/opengapps/arm/releases/download/20180910/open_gapps-arm-8.1-pico-20180910.zip

This is talked about in a few other places, sounds like something changed in opengapps and it's afecting lineage builds, etc, too. https://www.reddit.com/r/LineageOS/comments/9jaho1/android_auto_on_lineageos_151/