Trane Furnace CL2.001.04 Error Code — Meaning & Causes (2026)
PS1 Open — the 1st-stage pressure switch will not close. Below: what triggers it and what to check — this code carries no single repair to price. Reviewed July 2026.
What CL2.001.04 means
PS1 Open — the 1st-stage pressure switch will not close.
Likely causes, most common first
- Pressure switch contacts stuck open
- Pressure switch tubing not connected or restricted
- Vent piping restricted or improperly sized
- Flue gas condensate backing up in the secondary heat exchanger
Base: 1 published national repair-cost guide (retrieved 2026-07) · full source registry on the methodology page · Code meaning & causes · Reviewed July 2026
No single repair to price for this code
CL2.001.04 doesn't point at one failed component, so we don't attach a price module — forcing a repair mapping here would be dishonest. If the code keeps returning, the underlying symptom (not the code) is what gets priced: browse the gas furnace repair costs for the problem you're actually seeing.
Codes are universal — your location changes the repair price, never the code's meaning. See the methodology for the exact localization formula and sources.
Reviewed by a Red Seal–certified appliance technician who also holds a Technical Safety BC gas ticket (Gas-C) and an ODS/halocarbon refrigerant ticket (CFC/HCFC/HFC).