Faucets & Sensors error codes, explained
Manual and automatic faucets. Codes below: Aerators, batteries, sensor guides. Each guide covers what the code means, what you can safely try yourself, when to stop and call a technician, and what the repair typically costs.
One faucet running weak — the aerator
Family Handyman states it plainly: weak flow from a single faucet is usually a clogged aerator, and the most common clog is mineral scale. The aerator is the little screen assembly at the spout tip — unscrew it, pick out the debris, soak in vinegar, done. (Weak flow at EVERY fixture is a supply/pressure issue — different problem, see a plumber.)
Automatic faucet stopped working
The documented causes, in order: dead or low batteries (Sloan's low-battery signature is an intermittently flashing red LED; Moen specifies checking installation and using alkalines), a dirty or obstructed sensor lens (including protective stickers never removed after install — genuinely documented), and the same clogged aerator that afflicts manual faucets. No water at all with good batteries points to the solenoid valve.