What this code means
Bosch defines E05 as a wash arm diverter circuit fault in the main control board. In plain terms, the dishwasher has detected an electronic problem in the circuit that drives or monitors the diverter system controlling water distribution to the spray arms. This is a control and electronics fault, not a simple fill or drain warning.
Bosch’s official guidance is to perform a power reset at the breaker for 30 seconds. If the code returns after the reset, the manufacturer recommends contacting Bosch support or a qualified service technician. The problem is rooted in the control electronics rather than something a user can clear with routine maintenance.
Before You Replace Anything
Homeowners sometimes replace the entire main control board without confirming the fault. Always perform a power reset at the breaker first and inspect the diverter circuit wiring and connectors for damage or corrosion before ordering a new board.
Common Causes
- Defective water-switch Triac on the main control board Field repair sources identify a failed Triac component on the control board as the most frequent underlying fault for E05.
- Main control board or power module failure Bosch documentation points to the control board itself as the primary fault domain for this error code.
- Damaged or shorted diverter circuit wiring Loose connectors, damaged insulation, or shorts in the harness to the diverter assembly can trigger the error.
- Faulty wash arm diverter assembly A mechanical or electrical fault in the diverter motor or its feedback circuit can register as a control board error.
- Damaged float or float switch Some technicians report water-level or overfill issues associated with E05 on certain units, though this is not Bosch’s primary published cause.
Step-by-Step Fix
- Turn off power at the circuit breaker and wait 30 seconds to reset the dishwasher’s main control board.
- Restore power and run a short test cycle to see if the E05 code returns.
- If the code returns, turn off power again and remove the lower access panel or kick plate to access the control board and diverter assembly.
- Inspect the main control board for visible signs of damage, burned components, corrosion, or loose connectors.
- Check the wiring harness to the wash arm diverter assembly for continuity, shorts, damaged insulation, or loose plugs.
- Examine the float and float switch for debris, damage, or standing water in the base if the dishwasher shows any water-level abnormalities.
- Replace the failed component only after confirming the fault path. If the reset does not clear the code and you cannot isolate the defect, contact Bosch support or a qualified technician.
Parts Often Needed
| Part | Notes |
|---|---|
| Bosch dishwasher main control board | Amazon | Confirm your model number and verify the board part number before ordering. The water-switch Triac is on this board. |
| Wash arm diverter assembly | Amazon | Includes the diverter motor and feedback circuit. Order the assembly matched to your dishwasher model. |
| Float switch | Amazon | Replace if damaged or if water-level faults accompany the E05 code on your unit. |
When to Call a Pro
Call a professional if the E05 code returns after a power reset and you are not comfortable working with control boards or tracing electrical circuits. Diagnosing a Triac fault or control board defect requires multimeter testing and knowledge of the dishwasher’s wiring schematic. A qualified technician can pinpoint whether the fault is in the board itself, the diverter assembly, or the wiring harness and replace only the necessary component. Bosch recommends service intervention when the reset does not resolve the code.