Recalibrate the Sunroof (One-Touch)

On a sunroof-equipped 300, a classic post-battery-disconnect symptom is that the vent (tilt) function still works when you hold the switch, but one-touch Open and Close do nothing. The power sunroof has lost its position calibration and no longer knows its travel limits. A brief relearn from the driver’s seat teaches it the closed position again. This applies only to cars fitted with the factory power sunroof. Keep hands and objects clear of the opening throughout.

How you know it needs a relearn

The signature on the 300 is a split personality: press and hold and the glass still tilts up to vent, but a single tap for full Open or auto-Close gets no response. It usually follows a battery change or a headliner or overhead-console job. If the glass instead grinds, reverses partway, or sounds like it is fighting the track, that is a binding or obstruction problem — stop and clear it rather than forcing the calibration.

1. Turn the ignition to the Run position.
2. Press and hold the VENT button until the glass reaches the full-vent position and the motor has stayed stopped for at least one second.
3. Briefly press and hold the CLOSE switch, then release; the glass should travel to the fully closed position.
4. Confirm normal operation — one-touch Open and Close should work again.

Why it happens

The sunroof module counts motor rotations from its stored endpoints to know where the glass is and when to stop or auto-reverse. A battery disconnect erases those reference points, so the module keeps the simple held-button vent function — which needs no memory — but disables the automatic one-touch modes until it relearns the closed stop.

If it doesn’t work or common mistakes

• Let the motor sit fully stopped for a full second at the vent position before you press Close, or the module won’t register the endpoint.
• Clear leaves and grit from the track first; debris on this platform’s rails is a frequent cause of an incomplete relearn.
• If the glass won’t reach full close or reverses on its own, do not force it — that points to an obstruction or a stored motor fault.
• Replacing the sunroof motor or module is different: after that, the shop must run the separate multi-cycle excessive-force (anti-pinch) calibration, a safety routine this simple position relearn does not cover.

Keep the tracks clear and the corner drains open and your 300’s sunroof should hold its calibration between battery services.