Sensor and vibration test

When to test the sensors

Test the sensors when you look at a used phone or tablet, after a screen or board replacement, and when the screen won't rotate, the compass points the wrong way or the phone won't vibrate. Sensors rarely get a look in a quick try-out, but games, maps and auto-rotate all depend on them.

Common faults and their causes

• Readings that don't change when you tilt the device: a failed accelerometer or gyroscope, usually after a hard drop or a board replacement.
• No auto-rotate: very often just the rotation lock in Control Center (iPhone) or the quick settings panel (Android). Check that first.
• A compass that points the wrong way: metal or magnets nearby (magnetic cases, magnetic mounts). Remove the case and move the phone in a figure of eight to calibrate it.
• No vibration: a dead vibration motor, or vibration turned off in settings. Browsers on iPhone don't let websites drive the motor, so test it with the silent switch or an incoming call.

What to do if you find a fault

• Turn off rotation lock, remove any magnetic case, restart the device and test again.
• The proximity sensor (which turns the screen off at your ear) can't be tested from a web page: make a call and hold the phone to your ear.
• More: how to check a used Android phone.