Thermador Dishwasher E02 Error: Heater Relay Fault
thermador dishwasher e02 error indicates heater relay fault. Stop using the appliance and call a Thermador-certified technician immediately for diagnosis. What Does Thermador Dishwasher Error Code E02 Mean? The E02 error code on a Thermador Sapphire, Star-Sapphire, Emerald, or Topaz dishwasher indicates a fault in the primary heater relay on the main control board. The […]
Quick Assessment
Answer to continue safely
Is it safe to keep using?
No. A welded-closed relay is a fire and electrical hazard — the heating element may stay energized after the cycle ends. A failed-open relay means no sanitization. In both cases, stop using the dishwasher and arrange service promptly.
Can I reset the code?
Yes. A breaker reset clears the fault flag temporarily. If E02 returns on the next cycle, the relay has physically failed and the control board must be replaced. Resetting without repair is not a safe long-term solution.
When to stop immediately?
Stop if you notice: E02 returns on every cycle after the breaker reset, Burning smell or heat from the kickplate area between cycles.
Symptoms You May Notice
Dishwasher stops before or during the heating phase
The unit fills and begins the wash program but halts when the control attempts to energize the heating relay, displaying E02 before water temperature rises.
Dishes emerge clean but stone cold after a full cycle
On cycles where E02 only trips a warning rather than an immediate lockout, the wash completes mechanically but the water never heated to the required temperature.
E02 appears consistently at the same point in the program
Unlike transient faults, E02 from a failed relay appears at the identical program phase on every cycle — the moment the control board first commands the heater relay to close.
Possible Causes
Failed heater relay on the main control board
The electromechanical relay that switches line voltage to the heating element has failed open and cannot energize the element when commanded.
Requires ProfessionalWelded or stuck-closed heater relay
The relay contacts have welded together in the closed position, meaning power flows to the element continuously. The control board detects abnormal feedback and raises E02.
Requires ProfessionalDamaged wiring between relay output and heating element terminals
A break or short in the wires between the relay output and the element terminals causes the control to read incorrect relay state and flag E02.
Requires ProfessionalSafe Checks You Can Do
-
1
Reset the dishwasher at the circuit breaker
Turn off the dedicated circuit breaker for 60 seconds, then restore power. A power cycle reinitializes the control board relay diagnostics. Run a short test cycle and observe whether E02 returns at the start of the heating phase.
If E02 clears after the reset and the next cycle completes with warm dishes, the fault was a transient relay feedback error. Monitor subsequent cycles — if E02 returns, the relay is intermittently failing.
-
2
Feel the tub walls after the cycle to assess heating
After completing a full cycle, open the door and touch the interior stainless walls. Warm walls confirm the heating element ran at some point. Cool walls throughout indicate the heater never activated and E02 is a genuine relay failure.
The interior walls of a Thermador Star-Sapphire dishwasher should be distinctly warm — almost too hot to hold — within the first 15 minutes of a high-temperature cycle.
When to Call a Professional
Contact a qualified technician if:
- Heater relay on the control board measures open circuit across its output contacts when coil is energized
- Relay contacts show visible arcing or burn marks under inspection
- Heating element has continuity but E02 still appears — indicating relay driver failure on the board
Need Professional Help?
Find qualified technicians in your area for proper diagnostics and repair.
Dishwasher Repair Service Schedule Appointment