Trane

Ignition

Lockout

Trial / retry (door-card confirm)

HSI / gas / flame prove. If THIS door prints E2.1, treat it as retry lockout the same way as the S9 IFC — confirm the card. Do not invent a different title.

Walk Ignition in Diagnose

5 plates — walk the one on the cabinet

First check

1 Ohms at the igniter, then at the IFC

On Trane S8B1 measure cold ohms at the igniter plug, then at the IFC connector. An open at the plug is the element or local harness. Open only at the IFC is the harness rub-through on the collector. This is Category I metal vent. There is no 96% collector or PVC trap to prime.

Expect: Nitride cold ohms per THIS door sticker — do not use an 80% Norton chart.

The rest of the walkthrough is Diagnose.

On the plates

Watch a try: inducer, draft prove, HSI, valve, flame.
A draft fail first is not an igniter. Fix metal-vent prove before you condemn the nitride.
This is Category I metal vent. There is no 96% collector or PVC trap to prime.
Cap, liner, common-vent tables, inducer wheel, hose on the inducer housing.
Watch one try: inducer → PS → glow → valve click → flame. The dead step is the repair.
HSI ohms cold vs the sticker in this heat section. 24 VAC at the valve during trial.
Inlet gas on the roof. Long gas pipes and a undersized regulator starve a 250 kBtu section.

Plates that use Ignition

S8B1
S-series · single-stage · 80% · basic
Diagnose S8B1 — Sign in
S8X1
S-series · single-stage · 80% · Cat I
Diagnose S8X1 — Sign in
S8X2
S-series · two-stage · 80% · Category I metal vent
Diagnose S8X2 — Sign in
XC80
Legacy 80% · XC / XV / XL / XR · Cat I
Diagnose XC80 — Sign in
YSC
Precedent packaged · Reliatel · 3–10 t class
Ignition lockout
Trial for ignition failed after the IGC retries.
Diagnose YSC — Sign in

Same number, other makers

Ignition on Trane is not the same code on these plates.