The Bosch WTMC3521UC Dryer has some known problems that occur often. Here are some easy to do solutions for the problems or error codes your Bosch might be giving you.
The 'Start/Stop' indicator light does not illuminate due to a loose lightbulb.
The lint filter LED blinks after the lint filter has been cleaned. This blinking is not indicative of a problem; it serves as a reminder.
A warning signal is emitted, and the display shows 'E:01'. This indicates that the degree of drying has not been reached, or the drying time is too long.
The drum light fails to function because no program is selected, or the lightbulb is defective or burned out.
The display may indicate 'E:03'. This could be due to the main plug not being inserted at all or not inserted correctly, a tripped power supply fuse, the 'Start/Stop' button not being pressed, no program being selected, or the door not being closed.
Your dryer outputs different signals if the 'Signal' button is pressed. These include a start short tone, a sequence of short tones at the end, a sequence of long tones for mal-operation, and a sequence of long tones for a warning of malfunction.