Bosch E02 Error Code - Causes & Fix

What this code means

Bosch E02 indicates a main control board relay fault. On most Bosch dishwashers this code points to a problem with the relay on the control board that drives the heating circuit. On some model families Bosch describes it as a heat pump motor circuit fault at the main control board. Either way, the control board cannot energize the heating or heat-pump load correctly.

This is not a simple user-reset issue if the code returns after you restore power. The fault is inside the control board relay path or in the wiring and sensors that feed back to it. Bosch’s own troubleshooting instructions say to reset power at the breaker for thirty seconds. If E02 clears and stays gone, no further action is needed. If it comes back, contact Bosch Customer Support or have a technician inspect the control board, wiring, and sensor circuit.

Before You Replace Anything

Homeowners sometimes replace the heating element or temperature sensor first. Before ordering parts, check all connectors at the control board for looseness or corrosion and perform a thirty-second breaker reset to rule out a transient fault.

Common Causes

• Failed relay on the main control board The relay that switches the heating circuit has burned out or stuck, preventing the board from energizing the heater or heat pump motor.
• Control board or power module failure The main control board itself has failed beyond just the relay, often due to age, moisture, or voltage spike damage.
• Loose, corroded, or damaged wiring and connectors Connections between the control board and the heating circuit have corroded or backed out, causing intermittent or complete loss of the relay signal.
• Faulty temperature sensor or thermistor On some models the sensor that monitors heating can drift out of range or short, tripping the control board relay fault logic.

Step-by-Step Fix

1. Turn off power at the breaker for thirty seconds, then restore power. Bosch instructs this reset step first for E02.
2. Run a test cycle and watch the display. If E02 does not return, the fault was transient and no further action is needed.
3. If E02 returns immediately or mid-cycle, turn off power again and open the dishwasher door to access the control board area, usually behind the lower kickplate or inside the door panel.
4. Inspect every connector on the main control board for looseness, corrosion, or heat damage. Remove and reseat each plug, then check pin contacts for discoloration.
5. Check the temperature sensor connector if your model has one visible near the sump or heating element. Look for corrosion or a backed-out plug.
6. If all wiring is clean and tight, the fault is inside the control board relay or the sensor itself. Replace the main control board or power module as the primary repair, or test the temperature sensor resistance against your model’s service table if available.
7. After part replacement, run a full cycle to confirm E02 does not return and the dishwasher completes the heating phase normally.

Parts Often Needed

When to Call a Pro

Call a professional if the E02 code returns after a thirty-second breaker reset, or if you are not comfortable removing the dishwasher door panel or kickplate to access the control board. Diagnosis requires inspecting live 120 V connections, testing sensor resistance, and verifying incoming supply voltage. If wiring and sensors test normal, the technician will replace the main control board or power module. Bosch recommends contacting Bosch Customer Support or having an electrician check incoming voltage if the fault persists, so professional diagnosis is the safest path for a recurring E02.