P0045 — Turbocharger/Supercharger Boost Control A Circuit/Open

P0045: Turbocharger/Supercharger Boost Control A Circuit/Open — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Turbocharger/Supercharger Boost Control A Circuit/Open. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • Engine fault indicator with diminished boost or poor acceleration.
  • Protective reduced-power mode may engage when boost control is unavailable.

Possible causes

  • Open wire, disconnected plug or corroded connector in turbo/supercharger boost control A circuit.
  • Open-circuit boost actuator or control solenoid, fuse/supply defect.
  • Less often, ECU output problem after correct circuit testing.

What to check

  • Verify P0045 with freeze-frame; identify boost-control A architecture for this engine.
  • Inspect wiring, fuses and connectors around the boost solenoid or electric actuator.
  • With components isolated as OEM requires, check continuity, supply and command; an 'open circuit' DTC is not itself proof of a failed turbo.
  • Perform approved scan-tool actuator function tests and compare boost demand against measured pressure.
  • Repair circuit or replace only proven defective actuator/solenoid, then recheck under manufacturer-prescribed driving conditions.

Also written as: P0045-00, P004500, PO045 (some scan tools add the fault-type byte, e.g. -00).