Bosch Dishwasher Error Code E08

Bosch Dishwasher Error Code E08 — Meaning, Causes & Fixes

What E08 means: On many Bosch dishwashers, the error code E08 indicates a heating-related fault. The appliance is reporting that water temperature did not rise as expected during the cycle or that the control electronics are detecting a fault in the heating circuit. This can be caused by a failed heating element, a defective temperature (NTC) sensor, a bad heating relay/triac on the main control board, wiring/connectors that are corroded or open, or a safety component such as a thermal fuse.

Why it occurs and how it impacts you: When the dishwasher cannot reach or measure the proper wash temperature the unit may lengthen cycles, fail to complete on schedule, perform poor cleaning or drying, and be unable to run high-temperature sanitizing programs. In some cases the dishwasher will lock the cycle and display E08 until the fault is addressed. There are safety and appliance longevity concerns: a shorted heating element or damaged wiring can create an electrical hazard, while a non-heating dishwasher may not sanitize dishes properly and can lead to persistent odors and increased energy use as the control tries repeatedly to heat water.

Common Causes

• Failed heating element (open or shorted)
• Defective temperature sensor (NTC thermistor) or poor sensor connection
• Bad relay or triac on the main control board that switches the heater
• Burnt or damaged control board electronics
• Wiring harness issues: loose, corroded, or broken connectors
• Tripped thermal fuse or other safety cut-out
• Low incoming water temperature or incorrect water supply
• Severe scale build-up on the heater causing reduced heat transfer

Troubleshooting Steps

1. Safety first: disconnect the dishwasher from power (turn off the breaker) before inspecting electrical components. Do not attempt live testing unless you are qualified.
2. Power-cycle the appliance: switch power off for 1–2 minutes and then back on. Sometimes an intermittent error clears and reveals if it was a transient glitch.
3. Run a diagnostics/service mode if your model supports it to capture the heater/NTC readings and see if the code reappears. Consult your Bosch service manual for the exact sequence to enter diagnostics.
4. Check water supply: ensure hot water enters the machine (hot tap) and that the incoming water temperature is adequate for the selected program. Cold feed can make the controller think heating failed.
5. Inspect visible wiring and connectors around the heater and control board for burned insulation, corrosion, or loose pins. Repair any damaged connectors before further testing.
6. Measure the heating element for continuity with a multimeter. An open element usually means replacement is required. Also inspect visually for signs of burning or scale coating.
7. Test the temperature (NTC) sensor wiring and resistance. Compare readings with the service manual or parts specification. A sensor out of spec or intermittent will trigger E08.
8. Inspect the control board where the heater relay or triac is located. Look for burnt components, bulging capacitors, or cracked solder joints. If the relay/triac is failed it may need board repair or replacement.
9. Check for a blown thermal fuse or other safety devices in the heater circuit and replace if open.
10. Remove scale buildup: if the element is coated in lime scale, descaling procedures or element replacement may be necessary to restore proper heat transfer.
11. After replacing a suspected failed part (element, sensor, wiring, or board), restore power and run a short program to verify the E08 no longer appears and that water heats properly.
12. If the fault persists or you’re not comfortable working with mains voltage, contact Bosch service or a qualified appliance technician.

Maintenance / Prevention Tips

• Run the dishwasher on a hot cycle weekly to reduce residue and bacteria build-up.
• Use a rinse aid and the correct dishwasher detergent to reduce scale and spotting.
• Install a water softener or use dishwasher-safe water softening tablets in hard-water areas to prevent scale on the heating element.
• Clean filters and spray arms regularly so sensors and pumps are not overworked.
• Descale the machine periodically with a manufacturer-approved descaler to keep the element free of limescale.
• Avoid overloading the dishwasher which can extend cycle times and reduce heat transfer efficiency.
• Check and tighten visible electrical connectors annually during routine maintenance.
• Avoid using extension cords or multiple adapters; ensure the dishwasher is on a proper circuit with correct voltage.
• Ensure the dishwasher door closes properly—poor seal or door issues can cause repeated heating attempts.
• Inspect the float and inlet valve periodically to ensure correct water level and flow.
• Keep vents and pump areas free of debris that could cause the unit to overwork.
• Have a qualified technician perform an annual inspection of the heating circuit and control board connections.
• Use dishwasher-safe cups and items only; avoid putting insulating materials that could block heat sensor airflow.
• Replace aging rubber seals and hoses before they fail and cause secondary issues that might affect electronics.
• Follow manufacturer guidelines for loading, detergents, and cycle selection to reduce strain on the heating system.

FAQs

Conclusion / Safety Notice

If you see E08 on your Bosch dishwasher, treat it as a heating-circuit fault that warrants prompt attention. Always disconnect power before inspecting internal parts. Simple issues such as a loose connector or cold incoming water can sometimes be resolved by the user, but faults involving the heating element, main control board, or internal wiring should be handled by a qualified appliance technician. Working on live mains components carries the risk of electrical shock or fire—if you are unsure, call Bosch service or an authorized repair professional.

When in doubt, stop using the appliance, isolate power, and contact a certified technician. Replacing the proper defective component promptly not only restores cleaning and drying performance but also prevents safety hazards and potential further damage to your dishwasher.