FieldBench
Bosch codes

Bosch

P1

Lockout

High pressure switch

HPS opened (airflow, overcharge, restriction, or failed switch).

Walk P1 in Diagnose

Sign in for the next measurement

First check

1 Heat rejection first

On Bosch BOVA 2.0 high pressure is outdoor airflow until proven otherwise. Fan running the right direction, coil clean, fins not folded, no recirc over a fence or through a garage. Outdoor fan and coil. Indoor filter/coil.

Expect: OD fan on, coil clean, discharge air leaving the top/side freely.

The rest of the walkthrough is Diagnose.

On the plates

  • Outdoor fan and coil. Indoor filter/coil.
  • HPS (2 yellow leads on IDS) ohms closed when idle and cool.
  • Charge is weigh-in / Bosch subcooling chart — not piston SH.

Plates that use P1