Step 01
Use the documented 5-second pairing sequence.
Sennheiser’s instruction manual says to switch the headphones off, put them close to the Bluetooth device, and press the multi-function button for 5 seconds. The LEDs show a white continuous sequence and a pairing melody plays. Select MOMENTUM 4 on the host.
Step 02
Remove the host’s stale pairing record.
If Momentum 4 is already listed but will not reconnect, forget/remove the device from the host Bluetooth settings, toggle Bluetooth off and back on, and pair again. This is less disruptive than factory-resetting the headphones.
Step 03
Use Sennheiser Smart Control to inspect saved connections.
Sennheiser documents a Connections function in Smart Control for selecting paired devices and removing pairing information. The headphones can save multiple profiles, so an old or unexpected active connection can matter.
Step 04
Test another phone or computer.
If the headphones pair normally with another device, focus on the original host’s Bluetooth stack, saved device record, updates, or radio. If they fail on every host, continue with the headphone-side reset/support path.
Step 05
Use the hardware reset for malfunction, not as the first pairing step.
Sennheiser’s current support guidance says to hold the multi-function button for approximately 20 seconds when the headphones are not functioning correctly; a small tick confirms restart. Factory-default reset options can also exist through Smart Control/current product support. Follow the current Sennheiser support page if the app/manual version differs.
Decision
Do you need replacement headphones?
If forgetting/re-pairing or another host works, keep the headphones and fix the host pairing state.
If only one radio/OS fails, troubleshoot that host before replacing hardware.
If Momentum 4 cannot enter pairing mode or connect to multiple known-good hosts after Sennheiser’s documented reset/support steps, contact Sennheiser.
Sources