P0045 means Turbocharger/Supercharger Boost Control A Circuit/Open. There is an open or electrical fault in the circuit of the boost control solenoid or electronic turbo actuator. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0045 means
Modern engines measure boost and fuel rail pressure and compare them with a desired value calculated from engine speed, load and throttle. When actual pressure falls short of desired for long enough, the computer sets a code and often reduces power to protect the engine. Watching desired and actual values side by side on a scan tool shows whether the shortfall is constant or only appears under load.
P0045 symptoms
- Loss of power or reduced-power mode
- No boost or too much boost
Common causes of P0045
- Failed boost control solenoid or electronic actuator
- Open wiring or a damaged connector
- Blown fuse in the actuator circuit
How to diagnose P0045
- Check the actuator connector and wiring
- Check power, ground and the control signal
- Command the actuator with a scan tool
Can you drive with P0045?
Gently; repair soon.
P0045 tips
Some electronic turbo actuators need a calibration or learn after replacement; follow the procedure for your engine or the new actuator may not work correctly. An open circuit code is electrical, so start at the connector and fuse before suspecting the turbo itself; heat near the turbo makes connectors brittle and wiring insulation crack.
Will P0045 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0045 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0046 | Turbocharger/Supercharger Boost Control A Circuit Range/Performance |
| P0299 | Turbocharger/Supercharger A Underboost Condition |
| P0234 | Turbocharger/Supercharger A Overboost Condition |
Guides that help
When it is more than a sensor
Our superchargers page lists supercharger kits, and diesel owners can read the 6.7 Cummins turbo guide. If a failed turbo or fuel pump has damaged the engine, compare engines by code on our engines page.
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