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Error code reference

Thermador Cooktop Error Code FOP

No communication between the right ELIN and left ELIN on starting superbooster function.

Thermador codesThermador cooktop codes

No communication between the right ELIN and left ELIN on starting superbooster function.

First step from the service manual

Disconnect the cooktop from the power grid, check connections especially the connection between both ELINs (CNT7-CNT6) and the relay board connection. If failure continues, replace the relay board, then right ELIN, then left ELIN.

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

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What FOP means on a Thermador cooktop

The FOP error code on a Thermador cooktop indicates a loss of communication between the right ELIN (Electronic Induction unit) and the left ELIN when the superbooster function is activated. The superbooster feature works by allowing two adjacent induction zones to share power output, effectively doubling the energy delivered to one zone. This coordination requires the two ELIN modules to communicate with each other in real time. When the cooktop cannot establish or maintain this inter-module communication at startup of the superbooster, it triggers the FOP fault and disables the function to prevent unsafe or uncontrolled operation.

The communication between the right and left ELINs runs through a dedicated connector path, specifically the CNT7 to CNT6 connection. This wiring harness also interfaces with the relay board, which acts as a switching intermediary in the system. A loose, corroded, or damaged connection at any point along this path is the most frequent cause of the FOP code. Physical inspection of the CNT7 and CNT6 connectors should include checking for bent pins, oxidation, and secure seating.

If connection integrity is confirmed and the fault persists after a power cycle, the relay board is the next component to suspect, as it sits in the communication path between both ELINs. The recommended replacement sequence is relay board first, followed by the right ELIN, and then the left ELIN if the fault still cannot be resolved. This order follows a logic of replacing the least expensive and most accessible component before committing to the costlier ELIN modules.

Source: manufacturer service documentation.

Common causes of FOP

  1. 01

    Loose or disconnected CNT7-CNT6 connector

    Wiring / connection

    The wiring harness connecting the right and left ELIN modules at connectors CNT7 and CNT6 may have worked loose over time from vibration or thermal cycling. Inspect both connector ends for secure seating, bent pins, and any signs of arcing or heat damage.

  2. 02

    Corroded or damaged connector pins

    Wiring / connection

    Moisture or grease contamination at the CNT7-CNT6 connection points can cause oxidation on the pins, increasing resistance and breaking the communication signal. Visually inspect the pins and use contact cleaner if corrosion is present.

  3. 03

    Failed relay board

    Part replacement

    The relay board sits in the communication path between the two ELIN modules. A failed relay board can interrupt the inter-ELIN signal even if all wiring connections are intact. Replacing the relay board is the first hardware replacement step after ruling out connection issues.

  4. 04

    Failed right ELIN module

    Part replacement

    If the relay board replacement does not resolve the fault, the right ELIN module is the next component to evaluate. An internal failure in this module would prevent it from initiating or responding to superbooster communication.

  5. 05

    Failed left ELIN module

    Part replacement

    If the relay board and right ELIN have been replaced without clearing the code, the left ELIN module is the final component in the diagnostic sequence and may have an internal communication fault.

See the test procedure for each cause

Frequently asked questions about FOP

What does FOP mean on a Thermador cooktop?
The FOP code means the cooktop detected a communication failure between the right and left ELIN modules when the superbooster function was activated. The superbooster feature requires both induction control modules to coordinate in real time, and the cooktop shuts down that feature when it cannot establish the necessary link. The fault points to either wiring connection problems or a failed component in the communication path.
Will resetting the cooktop clear the FOP error?
Disconnecting the cooktop from power and reconnecting it may temporarily clear the FOP code, but the error will return when the superbooster function is activated again if the underlying cause has not been addressed. A reset is a useful first step to confirm the fault is consistent, but it is not a fix. The wiring connections and components must be inspected and repaired to resolve the issue permanently.
Is it safe to use the cooktop while the FOP code is active?
The FOP fault specifically disables the superbooster function, so the cooktop may still operate normally on individual induction zones that do not use that feature. However, continued use without diagnosing the fault is not recommended, as an underlying wiring issue could worsen over time. Have a qualified technician inspect the cooktop before relying on it for regular use.
How do I fix the FOP error on my Thermador cooktop?
Start by disconnecting the cooktop from power and inspecting the wiring connections between the two ELIN modules, specifically the CNT7 to CNT6 connector path, as well as the relay board connection. Reseat any loose connectors and look for damaged or corroded pins. If the connections are secure and the fault returns, the recommended repair sequence is to replace the relay board first, then the right ELIN module, then the left ELIN module.
How much does it cost to repair a Thermador cooktop showing the FOP error?
Repair costs vary depending on which component has failed. If the issue is only a loose or damaged connector, the fix may involve minimal cost beyond a service call fee, which typically ranges from $75 to $150. Relay board replacement parts can range from $100 to $300, while individual ELIN modules are more expensive, often ranging from $200 to $600 or more per unit. Labor charges will add to these part costs depending on your location and service provider.

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