Home Product SupportIdentify a code

Trane S9V2, S9X1, S9X2 and S9B1 condensing furnace · exact showing

Trane S9V2, S9X1, S9X2 and S9B1 condensing furnace showing E18: meaning and exact next steps

E18 means Blower communication failure on the control. Trane lists this code in its S9V2 guide only. This answer applies only to Trane S9V2 two-stage variable-speed furnaces, and the S9X1, S9X2 and S9B1 condensing furnaces, whose integrated furnace control shows seven-segment display codes, as listed in Trane's installer's guides 18-CE01D1-1E-EN (S9V2, pages 96 and 97) and 18-CE12D1-1D-EN (S9X1, S9X2 and S9B1, page 108). The S9X guide lists E01 to E12; E13 to E18 appear in the S9V2 guide only. Codes with a decimal point, such as E2.1, are written the way the guides draw them. Other Trane furnace families use other controls and other pages.

On the covered Trane S9V2, S9X1, S9X2 and S9B1 condensing furnace, E18 means blower communication failure on the control. Trane lists this code in its S9V2 guide only. First, turn the furnace's power off at the switch for a minute and back on, and note whether E18 returns.

Part of Trane S9V2, S9X1, S9X2 and S9B1 condensing furnace error codes

Differential

Likely causes of “Trane S9V2, S9X1, S9X2 and S9B1 condensing furnace showing E18”, and how to tell them apart

  1. 1

    A communication failure on the control

    What separates it The display shows E18

    How to confirm Trane lists E18 in its S9V2 guide only

  2. 2

    A loose communication wire

    What separates it The code follows service

    How to confirm Technician inspection

  3. 3

    A blower motor that has failed

    What separates it The blower does not respond

    How to confirm Technician testing

  4. 4

    A control board fault

    What separates it The motor tests well

    How to confirm Technician replacement

  5. 5

    A power glitch

    What separates it The code clears after a restart

    How to confirm Watch the next cycles

Before you touch a setting

Record this first — changing settings destroys the evidence

  • That the display shows E18
  • Whether the blower runs
  • Whether the code clears after a power cycle
  • Recent service

Try in this order

0 of 8 completed

  1. What to do first

    Reversible

    Turn the furnace's power off at the switch for a minute and back on, and note whether E18 returns.

  2. Correct only the documented fault domain

    Reversible

    A communication failure on the control belongs to a technician.

  3. Turn the furnace off

    Reversible

    At the switch for a minute.

  4. Turn it back on

    Reversible

    Watch the display.

  5. Note whether E18 returns

    Reversible

    And when.

  6. Check the blower

    Reversible

    Does it start?

  7. Record the pattern

    Reversible

    Date and time.

  8. Call a technician

    Reversible

    If it returns.

Model-specific

What is true of this model and not of its siblings

A smart blower
The S9V2 uses a variable speed blower that talks to the control, so a lost connection shows as a communication code.
Trane's guidance
Turn the power off for a minute and back on; if it returns, a technician is needed.
The motor
A failed motor module can stop answering.
The harness
A loose connector can cause an intermittent fault.
Cost
Motors and boards are major parts.
Records
Keep the code history.
Why a blower talks
A variable speed blower is driven by a motor with its own electronics. The control tells it how fast to turn, and the motor reports back. A broken conversation stops the furnace, because it is not safe to run without airflow.
What the power cycle does
Turning the power off for a minute resets the electronics in both the control and the motor. If the fault was a glitch, the code will not return. If it does, a connection or a component has failed.
What to expect
The technician checks the wiring harness between the control and the motor, tests the motor, and if both are good replaces the control. Ask for the part price before the visit, since motors can be costly, and check the warranty.
What you may notice
The blower may not start at all, may run at the wrong speed or may stop after a short time. The display shows E18. If the blower works for a moment after a power cycle and then stops, the connection is probably intermittent.
Ask before you approve
Ask the technician which component is at fault, the control, the motor or the wiring, and ask for a price for each. A wiring repair costs little, while a motor or control replacement is larger. Check the warranty on both.

Stop boundary

When this stops being a self-service repair

  • !Never bypass, jumper or tape over a safety switch
  • !Stop for a carbon monoxide alarm, soot, scorch marks or flame outside the burner compartment
  • !Call a qualified technician for anything behind the furnace's panels
  • !If you smell gas, leave the building and call the gas utility from outside; do not use switches or phones inside

Evidence ledger

Sources behind this answer

01
Trane Installer's Guide 18-CE01D1-1E-EN: Integrated Furnace Control Display Codes (S9V2)
02
Trane Trane furnace diagnostic codes

Exact questions

Common questions

What does E18 mean on a Trane S9V2, S9X1, S9X2 and S9B1 condensing furnace?+

Blower communication failure on the control. Trane lists this code in its S9V2 guide only.

Does every Trane list it?+

Trane lists it in its S9V2 guide only.

Does a power cycle help?+

Once, to test.

Who repairs it?+

A technician.

Wrong device or version?

Match the path before repeating the steps.

Match another device