FieldBench
Trane codes

Trane

Comm / data pair

Lockout

ComfortLink indoor-outdoor drop

Stat, indoor, or outdoor off the bus. Outdoor silent while the indoor is calling is often this — or a dead drive. Check bus vs drive LEDs before you gauge.

Walk Comm / data pair in Diagnose

2 plates — walk the one on the cabinet

First check

1 Let it cool, then read the drive LED

On Trane XV18 overcurrent / overheat is often a dirty coil, a failed OD fan, or a locked compressor — not a dead inverter. Clear airflow, confirm the OD fan, and read the drive LED before you order a control. Data pair landing and polarity at outdoor, indoor, and stat. No 24V on the pair.

Expect: OD fan running. Coil clean. Drive LED decoded from THIS outdoor’s card.

The rest of the walkthrough is Diagnose.

On the plates

  • Data pair landing and polarity at outdoor, indoor, and stat. No 24V on the pair.
  • Outdoor board powered (line voltage). Comm LED vs inverter-fault LED — they are different stories.
  • Isolate: indoor-only bus, then add outdoor. A cooked drive can take the whole ComfortLink down.

Plates that use Comm / data pair

Same number, other makers

Comm / data pair on Trane is not the same code on these plates.