Bryant furnace: Code 45 — Control Circuitry Lockout
Professional repair
Bryant furnaces share the Carrier control platform — this code table applies to the equivalent Bryant models. Confirm against your unit's panel label.
What does code 45 mean on a Carrier furnace? Auto-resets after 1 hour. Official causes: gas-valve relay stuck open, flame-sense circuit failure, or a software check error. Reset power to clear; replace the control if it repeats.
GOOD NEWS: THE FIRST CHECKS ARE FREE AND TAKE MINUTES.
Try these first — in this order
One power-cycle (30 s) is the official reset.
If code 45 returns, the board gets replaced. DIY part cost: $120–250 — a pro visit for this class of fault typically runs $150–350.
What causes it (in order of likelihood)
- Control board internal fault TECH
Parts referenced by this code
Always match parts against your model's parts list — part numbers vary within a series.
Applies to
58STA · 58STX · Bryant 310/311/312 series · Payne PG8M series
Different Bryant generations use different code maps. If your series isn't listed, don't assume this meaning — check your blower-door label.
Verified against Carrier 58STA/58STX Installation & Service Instructions (1106202L), p.37/48
Last verified 2026-07-06 · how we verify