mypros+
Error code reference

GE Range Error Code F40x

LIN comm error to/from RPSM Aux Board (when equipped).

GE codesGE range codes

LIN comm error to/from RPSM Aux Board (when equipped).

First step from the service manual

Replace Aux board, especially if Main Board relays still function.

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 F40x.

  • 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 F40x means on a GE range

The F40x error code on a GE range indicates a LIN (Local Interconnect Network) communication failure between the main control board and the RPSM (Remote Power Supply Module) Auxiliary Board. This error only applies to range models equipped with the Aux Board. The LIN bus is a low-speed serial communication protocol used to pass control signals and status data between the two boards. When communication is interrupted or lost entirely, the main board logs the F40x fault and may restrict certain range functions.

The Aux Board handles supplemental relay or power distribution functions that the main board delegates through the LIN network. A communication failure can result from a faulty Aux Board, damaged wiring in the LIN communication harness, or a corroded or loose connector at either board. Because the main board's own relays can remain functional during this fault, the range may still partially operate, which is an important diagnostic clue.

The primary diagnostic approach is to first confirm that the main board relays are still functioning. If they are, this strongly suggests the Aux Board itself is the source of the fault rather than the main board. Inspect the wiring harness and connectors between the two boards for any signs of damage, heat stress, or corrosion before replacing the Aux Board. If the harness checks out, Aux Board replacement is the recommended corrective action.

Source: manufacturer service documentation.

Common causes of F40x

  1. 01

    Faulty Aux Board

    Part replacement

    The Aux Board itself is the most likely cause when the main board relays are still functioning normally. A failed internal component on the Aux Board can disrupt LIN communication entirely.

  2. 02

    Loose or disconnected LIN harness connector

    Wiring / connection

    A connector that has worked loose at either the main board or the Aux Board will break the LIN communication path. Check both ends of the harness for secure seating.

  3. 03

    Damaged LIN communication wiring

    Part replacement

    Physical damage to the wiring harness between the two boards, such as pinching, melting, or chafing, can interrupt the serial communication signal. Inspect the full harness run for visible damage.

  4. 04

    Corroded connector terminals

    Wiring / connection

    Corrosion or oxidation at the connector pins on either board can increase resistance enough to cause communication errors. Clean or replace affected connectors if corrosion is found.

  5. 05

    Faulty main control board

    Part replacement

    If the Aux Board and wiring are confirmed to be in good condition but the error persists, the main board's LIN transceiver circuit may be at fault. This is a less common cause and should be considered after other components are ruled out.

See the test procedure for each cause

Frequently asked questions about F40x

What does F40x mean on a GE range?
The F40x code on a GE range indicates a LIN communication error between the main control board and the RPSM Auxiliary Board. This code only appears on range models that are equipped with the Aux Board. It means the two boards have lost the ability to communicate over their internal serial network, which can limit some range functions.
Can I fix the F40x error myself on a GE range?
A knowledgeable DIYer can start by inspecting the wiring harness and connectors between the main board and the Aux Board for loose, corroded, or damaged connections, as these are simple to address without replacing parts. If the connectors look good and the main board relays are still functioning, the Aux Board is the most likely faulty component and will need to be replaced. Replacing the Aux Board requires comfort working inside the range control section and identifying the correct part for your model.
Is it safe to use my GE range while the F40x code is displayed?
Because the main board relays can remain operational during an F40x fault, the range may still heat partially, but operating an appliance with an active control communication error is not recommended. Certain safety-related functions managed by the Aux Board may not work correctly. It is best to resolve the fault before continued regular use.
How much does it cost to repair a GE range F40x error?
If only the wiring or connectors need attention, the repair cost can be minimal, covering just your time. If the Aux Board requires replacement, parts typically range from around $50 to $200 depending on the specific model, plus labor costs if a technician is used. A full service call from a professional technician generally runs between $100 and $300 or more in total.
Will resetting my GE range clear the F40x error code?
Resetting the range by disconnecting power for a few minutes may temporarily clear the F40x code, but the error will return if the underlying communication fault between the main board and the Aux Board has not been corrected. A reset is useful for confirming whether the fault is intermittent, but it is not a repair. The wiring and boards need to be inspected and repaired or replaced to permanently resolve the issue.

Related GE range codes

All GE range codes
View all 303 GE range codes

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

Get Started

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