Trane S8B1A040M3PSCA/C - Troubleshooting; 3.3 Fault Code

66
S8XB-SVX001-1C-EN
See Note #1
Note #1
OL = Open Switch
0 ohms = Closed Switch
DEFINITION
An error has occurred with the PS2, indica!ng that the pressure
switch is closed when it should be open.
In most cases, the pressure switch is not the problem.
NOTE: Verify pressure switch wiring and tube rou!ng
are correct.
3.3 Fault Code
Cycle power OFF to the
furnace and remove
Brown wire from PS2.
NO
YES
Verify wiring. If
correct, replace IFC
Is con!nuity (0 ohms)
measured across PS2?
Replace pressure
switch and verify
opera!on
TTrroouubblleesshhoooottiinngg