800 Series SHP78CM5N: E0103/E0107 is a main-control relay family; repeating Sanitized-light flashes can belong to the same control path. Record the pattern, reset power for 30 seconds once and arrange Bosch service if it reappears. First preserve the exact display, timing and operating state: a similar-looking code in another appliance category can mean something else. Cancel the cycle, isolate power, close the water valve and let the tub cool. Wear gloves near filters because hidden glass may be present; do not tilt a built-in unit. After the documented check, use the result to separate a temporary condition from a fault that needs authorised service.
Models covered
Safety first
- Cancel the cycle, isolate power, close the water valve and let the tub cool. Wear gloves near filters because hidden glass may be present; do not tilt a built-in unit.
What the symptom may indicate
Checks in the right order
- Record the evidence
Photograph or write down “E0103 or E0107 main-control relay fault” before resetting anything.
- Make the appliance safe
Cancel the cycle, isolate power, close the water valve and let the tub cool. Wear gloves near filters because hidden glass may be present; do not tilt a built-in unit.
- Apply the official user check
Record the pattern, reset power for 30 seconds once and arrange Bosch service if it reappears.
- Decide after one test
If the exact symptom clears, monitor one normal use. If it returns, preserve the code and contact the manufacturer instead of guessing a part.
Stop and get qualified help when
- Stop for active leaking, water in the base, uncontrolled filling, burning smell or a heat, motor or control code that returns after one reset.
Next step
Repair, replace a part, or arrange a diagnosis?
Use the checks and stop conditions above to choose a cautious next step. A symptom alone never proves that the appliance has failed.
Resolve it without buying anything
Complete the 4 user-accessible checks in order. If normal operation returns and no warning sign remains, no replacement is indicated.
Replace only the confirmed part
If the checks isolate a worn or blocked component, match its complete reference to the exact appliance model before ordering.
This guide does not identify a replacement part. Do not order a generic component from the symptom alone.
Arrange a diagnosis before replacing the appliance
Stop at any warning sign listed above. A qualified diagnosis should confirm that repair is unsafe, unavailable or uneconomical before an appliance replacement is considered.
Sources used
- Bosch — Bosch's official support material documents “E0103 or E0107 main-control relay fault” and the user-safe decision retained here.
- Bosch — Bosch's official model page identifies 800 Series SHP78CM5N as the exact catalog appliance covered by this family guide.
Last checked: 30 August 2026