Toro TMC-212 "FUSE" & "dL y5" Errors: Causes & Reset

Understanding Toro TMC-212 Fault Codes

The TMC-212 displays "FUSE" with a station number when it detects excessive current draw (short) on that station's circuit. It bypasses the faulty station but continues running others. If the pump/master valve circuit faults, it shows "MV" and "FUSE" alternately and halts the program.

Code "dL y5" Explained

This appears to be a corrupted display or secondary fault indicator—often seen after power surges. The installer's note about sensitivity to surges is accurate; the TMC-212 benefits from a dedicated 120 V circuit with surge protection.

Immediate Steps

1. Press OFF to clear the warning display (does not fix the root cause).
2. Identify the faulty station: check solenoids for shorts (measure resistance: 20–60 Ω typical).
3. Inspect field wiring for nicks, water in splices, or rodent damage.
4. Test pump start relay coil if MV/FUSE appears.

Full Memory Clear & Reprogram

1. Dial → OFF.
2. Press NEXT → "CL" flashes.
3. Hold OFF until "CL" stops flashing (~5 sec).
4. Dial → RUN, then reprogram all schedules.

If faults recur after clearing, the controller's output triacs may be damaged from prior surges—replacement is advised.