Error code reference

Bosch Dishwasher Error Code 2

Heating system fault during test program

Bosch codesBosch dishwasher codes

Heating system fault during test program — heater, Hi-Limit, flow switch, NTC, or control module heater relay (on 2 & 3-digit digital displays).

First step from the service manual

Check heater (~11 ohms), high limit (~0.3 ohms), flow switch (~0.4 ohms), NTC (~55k ohms at 72°F), circulation pump (~10 ohms), control module heater relay, and wire harnesses.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 2 means on a Bosch dishwasher

Error code 2 on a Bosch dishwasher indicates the control board has detected a fault in the heating system. The board monitors the heating circuit and flags this code when it cannot confirm proper heater operation. The fault can originate from several components: the heating element itself, the Hi-Limit thermal cutout, the flow switch, the NTC temperature sensor, or the heater relay on the control module. Running the test program and measuring incoming current is the critical first diagnostic step. A reading of approximately 1.5A confirms the heater circuit is not drawing power, pointing to a failure somewhere in that circuit rather than a software or communication issue.

For homeowners, this error means your dishwasher is not heating the water or drying cycle properly. Without a functioning heater, dishes will come out cold, wet, and potentially not fully sanitized. The dishwasher may still run a full cycle but the results will be noticeably poor. The heating element is a resistive coil at the bottom of the tub, and the Hi-Limit is a safety device that cuts power to the heater if temperatures get dangerously high. Either of these can fail over time. The NTC sensor measures water temperature and tells the control board when to activate and deactivate the heater, so a failed NTC can also trigger this code even if the heater itself is functional.

Source: manufacturer service documentation.

Common causes of 2

  1. 01

    Failed heating element

    Part replacement

    The heating element has burned out or developed an open circuit, preventing it from drawing current. This is the most common cause and will produce the ~1.5A reading during the test program because no resistive load is present in the circuit.

  2. 02

    Tripped or failed Hi-Limit thermal cutout

    Part replacement

    The Hi-Limit is a one-time or resettable safety device that interrupts the heater circuit if water temperature exceeds a safe threshold. If it has tripped or failed open, the heater receives no power regardless of whether the element itself is good.

  3. 03

    Faulty NTC temperature sensor

    Part replacement

    The NTC sensor provides water temperature readings to the control board. If the NTC fails or reads out of range, the board may refuse to energize the heater or may log a heating fault even though the element is physically intact.

  4. 04

    Defective heater relay on the control module

    Part replacement

    The control board contains a relay that switches power to the heating circuit. If this relay has failed open, the board cannot deliver voltage to the heater regardless of the condition of the element, Hi-Limit, or NTC. This is less common but should be considered after ruling out the other components.

See the test procedure for each cause

Frequently asked questions about 2

What does error code 2 mean on a Bosch dishwasher?
Error code 2 signals a heating system fault. The control board has detected that the heating circuit is not functioning correctly, which can involve the heating element, the Hi-Limit thermal cutout, the flow switch, the NTC temperature sensor, or the heater relay on the control module. The board logs this code when it cannot confirm that the heater is drawing the expected current during operation.
How do I fix error code 2 on a Bosch dishwasher?
Start by running the dishwasher's built-in test program and measuring incoming current with a clamp meter. A reading of approximately 1.5A confirms the heater circuit has failed and is drawing no significant load. From there, check the heating element for continuity with a multimeter, inspect the Hi-Limit cutout, and test the NTC sensor resistance against the manufacturer's spec. Replace whichever component tests outside its acceptable range. If all components test good, the heater relay on the control board may be the cause.
Can I still use my Bosch dishwasher with error code 2 active?
The dishwasher will likely still run a cycle, but it will not heat water or dry dishes effectively. Dishes will come out cold and wet, and the wash will not reach the temperatures needed for proper sanitation. Running the appliance repeatedly in this state does not create a safety hazard, but the cleaning results will be poor. Resolving the fault before continued use is advisable if you rely on the dishwasher for sanitation.
How much does it cost to repair Bosch dishwasher error code 2?
A replacement heating element for a Bosch dishwasher typically costs between $30 and $80 for the part, and it is a moderate DIY repair involving removing the lower spray arm and basket to access the element. An NTC sensor is usually under $20. If the control board's heater relay is the cause and a full board replacement is needed, parts alone can run $150 to $300, making professional diagnosis worthwhile before committing to that expense. Labor from a technician for the full diagnosis and repair generally adds $100 to $200 depending on your area.
What is the Hi-Limit on a Bosch dishwasher and how does it cause error code 2?
The Hi-Limit is a thermal safety device wired in series with the heating element. It is designed to cut power to the heater if water temperature reaches an unsafe level, protecting the tub and components from heat damage. Once the Hi-Limit trips or fails in the open position, it breaks the heater circuit entirely, causing the control board to detect zero current draw from the heating system and log error code 2. Testing it with a multimeter for continuity will confirm whether it has opened and needs replacement.

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