"Lock screen" can mean two things, and the fix depends on which one you mean. There's your phone's lock screen (the one you see when the phone is in your pocket or on the dash) and the car's Android Auto display. They're controlled by different settings. Let's separate them.

Two different screens

If the car screen is blank, that's an Android Auto issue (jump to Blank car screen). If your phone lock screen stopped showing messages, use the steps below.

Show on lock screen

First, make sure lock-screen notifications are on at all:

  1. Settings → Notifications → Lock screen (or "Notifications on lock screen").
  2. Set it to "Show conversations, default, and silent" (or at least "Show all notification content"). If it's "Don't show notifications," nothing appears.
  3. Per app: Settings → Apps → [messaging app] → Notifications → make sure the category isn't set to "Silent" or "Minimized."

Android 14 sensitive content

Android 14 changed lock-screen privacy. Even with notifications "shown," message content can be hidden:

Locked phone in the car

When your phone is locked and sitting in the car (common with wireless Android Auto), two things interact:

Blank car screen

If the Android Auto car screen itself shows no notifications:

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FAQ

Why did my message content disappear from the lock screen?

Android 14 introduced stricter lock-screen privacy. If you set "Hide sensitive content" (or "Hide silent conversations") under Settings, Notifications, Lock screen, the sender and text are replaced with "Content hidden." Switch to "Show all notification content," and turn off any per-app "Hide content on lock screen" toggle in the messaging app's settings (common on Samsung One UI).

Is the Android Auto car screen the same as my phone lock screen?

No. The car screen is controlled by Android Auto's own notification settings and notification access, while the phone lock screen is controlled by Android's lock-screen notification setting. A blank car screen is an Android Auto problem; missing content on the phone lock screen is an Android privacy setting.

Why is the car screen blank when my phone is locked?

When the phone is locked and connected, Android Auto often routes notifications to the car display, so the phone shows little — that's normal. If the car screen is also blank, re-check Android Auto's "Show message notifications" toggle and notification access, and make sure the conversation isn't muted or battery-optimized.

How do I make notifications show full content on the lock screen?

Go to Settings, Notifications, Lock screen, and choose "Show all notification content." Also verify the messaging app's notification category isn't set to Silent, and disable any OEM "Hide content on lock screen" toggle inside the app's notification settings.