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Error code reference

Jenn-Air Cooktop Error Code Er 20

Flash failure; microcontroller (μC) is faulty.

Jenn-Air codesJenn-Air cooktop codes

Flash failure; microcontroller (μC) is faulty.

First step from the service manual

Disconnect power, replace the cooktop UI board, reassemble all parts and panels before operating.

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

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What Er 20 means on a Jenn-Air cooktop

Er 20 on a Jenn-Air cooktop signals a flash failure, meaning the microcontroller (μC) on the user interface (UI) board has experienced a critical internal fault. Flash memory is the non-volatile storage integrated into the microcontroller that holds the cooktop's firmware, calibration data, and operational parameters. When the μC cannot properly read from or write to this flash memory, or when the firmware becomes corrupted, the control system flags Er 20 and halts normal operation to prevent unsafe behavior.

The microcontroller is the central processing unit of the UI board, responsible for interpreting touch inputs, regulating burner output levels, and managing all cooktop functions. A flash failure typically indicates that the μC itself is faulty rather than a peripheral component, which means the entire UI board must be replaced. This type of failure can result from power surges or voltage spikes reaching the board, firmware corruption during a previous power interruption, or simply component degradation over time.

Because the fault is internal to the microcontroller's flash memory, there is no field-level repair for the chip itself. The correct resolution is full UI board replacement. Before replacing the board, disconnecting power to the unit is essential both for safety and to rule out any transient fault that may have triggered the error under unusual electrical conditions.

Source: manufacturer service documentation.

Common causes of Er 20

  1. 01

    Faulty UI board microcontroller

    Part replacement

    The microcontroller on the UI board has an internal flash memory failure. This is the primary cause identified for Er 20, and it requires replacing the entire UI board.

  2. 02

    Firmware corruption from power interruption

    Part replacement

    A sudden loss of power while the microcontroller was writing to flash memory can corrupt the stored firmware. This leaves the μC in a failed state that triggers Er 20 on the next startup.

  3. 03

    Power surge or voltage spike damage

    Part replacement

    A voltage spike from a utility event or nearby appliance can damage the microcontroller's flash memory circuits. Inspect for any visible burn marks or discoloration on the board as a secondary indicator.

  4. 04

    Component degradation over time

    Part replacement

    Extended use can degrade the flash memory cells within the microcontroller, eventually causing read or write failures. This is more common on older units and presents with no other identifiable triggering event.

See the test procedure for each cause

Frequently asked questions about Er 20

What does Er 20 mean on a Jenn-Air cooktop?
Er 20 indicates a flash failure in the cooktop's microcontroller, which is located on the user interface (UI) board. The microcontroller's internal flash memory has become corrupted or failed, preventing normal operation. This fault requires replacing the UI board to resolve.
Can I fix Er 20 on my Jenn-Air cooktop myself?
The repair involves disconnecting power to the cooktop and replacing the UI board. A knowledgeable DIYer comfortable working with appliance electronics can perform this replacement, but it does require sourcing the correct UI board for your specific model. Reassemble all parts and panels fully before restoring power and testing.
Will resetting the cooktop clear the Er 20 error?
Disconnecting power and waiting before restoring it is the first recommended step, but Er 20 is caused by an internal hardware failure in the microcontroller. A simple reset is unlikely to clear the fault permanently. If the error returns after a power reset, the UI board requires replacement.
Is it safe to use my Jenn-Air cooktop while Er 20 is displayed?
You should not continue using the cooktop while Er 20 is active. The microcontroller fault means the control system cannot reliably manage burner output or respond to user inputs. Operating the cooktop in this state could pose a safety risk.
How much does it cost to repair a Jenn-Air cooktop showing Er 20?
Repair costs vary depending on the specific cooktop model and labor rates in your area. The UI board part itself typically ranges from $150 to $350 or more, and professional labor can add $100 to $250 on top of that. Diagnosing the fault and sourcing the correct board for your model number before ordering is recommended.

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