mypros+
Error code reference

Fisher & Paykel Cooktop Error Code F12.4

Master temp bad

Fisher & Paykel codesFisher & Paykel cooktop codes

Master temp bad - Thermistor on the master PCB reports out of range temperature for 5 seconds (temp >185°F/85°C or temp <-22°F/-30°C).

First step from the service manual

Check master board thermistor.

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

MyPros+ Max

Get the full diagnostic procedure for F12.4.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What F12.4 means on a Fisher & Paykel cooktop

The F12.4 error code on a Fisher & Paykel cooktop indicates a fault with the thermistor located on the master PCB (printed circuit board). This onboard temperature sensor monitors the operating temperature of the master control board itself. When the thermistor reports a temperature above 185°F (85°C) or below -22°F (-30°C) for a continuous period of 5 seconds, the cooktop's control system logs the fault and displays F12.4. The temperature thresholds represent conditions outside the safe and functional operating range for the board's electronics.

The master PCB thermistor is a passive resistive sensor whose resistance value changes predictably with temperature. If the thermistor fails internally, develops a broken circuit, or experiences a poor solder or connector joint, it can report false temperature readings that fall outside the valid range. In these cases, the board itself may not actually be overheating or freezing, but the faulty sensor signal triggers the fault regardless.

Actual thermal conditions can also cause this code legitimately. Blocked ventilation beneath or around the cooktop can cause the master PCB to overheat and push the board temperature above the upper threshold. Conversely, in rare cases such as storage or operation in an extremely cold environment, a genuine low-temperature condition could trigger the lower threshold. Diagnosing whether the fault is a true thermal event or a failed sensor is the critical first step before replacing any components.

Source: manufacturer service documentation.

Common causes of F12.4

  1. 01

    Failed master PCB thermistor

    Part replacement

    The thermistor on the master board may have failed internally, causing it to report an out-of-range resistance value even when actual board temperature is normal. Check the sensor and its wiring connections for signs of damage or an open circuit.

  2. 02

    Loose or corroded thermistor connector

    Wiring / connection

    A poor connection at the thermistor's connector plug or solder joint on the master PCB can produce erratic or out-of-range resistance readings. Inspect the connector for corrosion, bent pins, or incomplete seating.

  3. 03

    Master PCB overheating due to blocked ventilation

    Wiring / connection

    If airflow around the cooktop's control electronics is restricted by debris, improper installation clearances, or a failed cooling fan, the board can genuinely exceed 185°F (85°C). Check that all ventilation slots are clear and unobstructed.

  4. 04

    Damaged wiring harness between thermistor and master PCB

    Part replacement

    Chafed, pinched, or heat-damaged wiring between the thermistor and the board can cause signal faults that mimic an out-of-range temperature reading. Inspect the harness along its full run for visible damage.

  5. 05

    Faulty or failing master PCB

    Part replacement

    If the thermistor and all associated wiring test as good, the master PCB itself may have a fault affecting how it reads or processes the thermistor signal. Board replacement would be required in this scenario.

See the test procedure for each cause

Frequently asked questions about F12.4

What does F12.4 mean on a Fisher & Paykel cooktop?
F12.4 indicates that the thermistor on the master PCB has reported a temperature outside the acceptable range for at least 5 seconds. The acceptable range is between -22°F (-30°C) and 185°F (85°C). This fault can be caused by a failed thermistor, a wiring or connector issue, or an actual overheating condition on the control board.
Can I fix the F12.4 error myself?
Some causes of F12.4 are DIY-accessible, such as checking and reseating the thermistor connector or clearing blocked ventilation around the cooktop. However, replacing the thermistor or the master PCB requires comfort working with appliance electronics and the ability to safely disconnect power before beginning any inspection. If you are unsure, a qualified appliance technician should perform the diagnosis.
Is it safe to use my cooktop while F12.4 is displayed?
You should not attempt to continue using the cooktop while this fault is active. The F12.4 code indicates the control board's thermal monitoring has detected a problem, and if the board is genuinely overheating, continued operation could cause further damage to the electronics. Disconnect power and investigate the cause before resuming use.
Will resetting my Fisher & Paykel cooktop clear the F12.4 error?
Cycling power to the cooktop may temporarily clear the fault display, but if the underlying cause is a failed thermistor, damaged wiring, or a ventilation problem, the F12.4 code will return once the cooktop is back in operation. A reset alone is not a fix and should only be used as part of the diagnostic process after addressing the root cause.
How much does it cost to repair a Fisher & Paykel cooktop showing F12.4?
Repair costs depend on the root cause. If the fix involves only reseating a connector or clearing a ventilation blockage, costs may be limited to a service call fee, typically in the range of $75 to $150. If the thermistor or master PCB needs replacement, parts and labor combined can range from $150 to $400 or more depending on part availability and local labor rates.

Related Fisher & Paykel cooktop codes

All Fisher & Paykel cooktop codes
View all 22 Fisher & Paykel cooktop codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass