Symptoms of P0045
- Check-engine light on, sometimes with rough or uneven running.
- Hesitation, surging, or a noticeable change in fuel economy.
- Occasionally hard starting or a smell of unburnt fuel.
Common causes of P0045
- A failing or contaminated sensor (MAF, MAP, oxygen or air-fuel sensor).
- Intake or vacuum leaks, or an exhaust leak near an upstream sensor.
- Wiring, connector, or fuel-delivery problems that skew the reading.
Useful checks before replacing parts
- Check boost control solenoid feed voltage, ground or driver command, resistance, connector fit, and continuity through the harness.
- Inspect wiring near turbo heat, vacuum hose routing if applicable, solenoid plumbing, connector corrosion, and fuse or relay supply.
- Compare commanded boost control with actual boost, wastegate or vane position data, load, and related underboost or overboost codes.
Related OBD-II codes
These nearby fuel / air entries can help compare wording and pin down the fault area.