FieldBench
Trane codes

Trane

Discharge / coil sensors

Protect

Outdoor thermistors

Discharge or outdoor-coil sensor open/short/out of range. ComfortLink will name which. Defrost and drive protection both lie when these are wrong.

Walk Discharge / coil sensors in Diagnose

2 plates — walk the one on the cabinet

First check

1 Is this cabinet actually twinned?

On a standalone Trane XV18, nothing belongs on the TWIN terminal. A leftover jumper throws this. AC-only outdoor. There is no RV solenoid and no defrost sensor to ohm.

Expect: TWIN empty on a single cabinet.

The rest of the walkthrough is Diagnose.

On the plates

  • Ohms vs the XV20i / 4TWV0 sensor chart. Connector at the drive.
  • A physically iced coil with a good sensor is airflow or charge — not a ‘bad defrost board’ from an XR14.
  • AC-only outdoor. There is no RV solenoid and no defrost sensor to ohm.

Plates that use Discharge / coil sensors