Bosch Dishwasher E02 Error — What It Means
Bosch lists the E02 error as a main control board relay fault or error. Independent repair sources commonly identify this as a heater relay fault on the control board, meaning the board is not switching the heating circuit correctly. The relay on the control board has failed or the board itself has developed a fault that prevents proper operation of the heating system. Bosch’s first troubleshooting step is to reset power at the breaker for 30 seconds to clear transient faults. If the code returns after the reset, a component-level failure is present and requires inspection or replacement.
Common Causes
- Failed relay on the main control board The relay that controls the heating circuit has failed and cannot switch the heater on or off correctly.
- Defective control board or power module The entire control board or power module has developed a fault beyond just the relay, requiring board replacement.
- Loose or corroded wiring to the control board Connectors or wiring between the control board and the heater circuit are loose, corroded, or damaged.
- Faulty temperature sensor or thermistor In some models a temperature sensor issue can trigger the same relay fault code when the board cannot read heating feedback correctly.
- Burned traces or connectors on the PCB The control board has visible burn marks, melted connectors, or damaged traces around the relay or heating circuit.
Step-by-Step Fix
- Turn off power at the breaker for about 30 seconds, then restore power to reset the dishwasher and clear transient faults.
- Run a test cycle to see if the E02 code returns after the reset.
- Unplug the dishwasher or switch off the breaker again, then remove the lower front panel or access panel to reach the control board and power module.
- Inspect the main control board for visible damage, burned traces, corroded connectors, or signs of relay failure around the heater circuit.
- Check all wiring and connectors from the control board to the heating element and verify they are secure, clean, and free of corrosion or overheating.
- Test the temperature sensor or thermistor if your model uses one in the heating control logic, and replace it if readings are out of spec or the sensor is open.
- Replace the control board or power module if the relay is integral to the board and testing confirms the board is the source of the fault, then restore power and run a test cycle to verify the repair.
Parts Often Needed
| Part | Notes |
|---|---|
| Main control board / power module | Amazon | Match the exact part number for your Bosch dishwasher model, as boards vary by series. |
| Temperature sensor / thermistor | Amazon | Only if your model uses a separate sensor in the heating circuit and testing shows it is defective. |
| Wiring harness or connector kit | Amazon | If inspection reveals burned, melted, or corroded connectors between the board and heater. |
When to Call a Pro
Call a qualified appliance technician if the E02 code returns after the breaker reset, if you are not comfortable working with electrical components and circuit boards, or if you lack the tools to safely access and test the control board. Bosch’s own support guidance directs homeowners to contact Bosch Customer Support if the power reset does not resolve the fault. A technician will verify the heater circuit, control board relay operation, wiring integrity, and any temperature-sensing components before replacing the defective part. Control board replacement requires correct part identification and careful handling of connectors, so professional service is often the most reliable path for this fault.