P0045: Boost control solenoid: open circuit
The ECU finds the circuit of the solenoid that controls turbo boost is broken; usually a connector, a wire or the solenoid itself.
| Code | P0045 |
|---|---|
| System | Engine and transmission |
| Group | P00xx, Air, fuel and emissions |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P0045 means
On turbocharged or supercharged engines, an ECU-controlled solenoid sets how much boost is produced, by acting on the wastegate or on the variable geometry vanes. This code means the electrical circuit of that solenoid is open. Without boost control, the engine normally goes into limp mode and cuts power to protect itself.
Most common causes
- Loose or corroded solenoid connector
- Broken or chafed wire
- Fuse or relay feeding the solenoid
- Open solenoid coil
- ECU fault (uncommon)
Symptoms
- Engine warning light on
- Clear loss of power (limp mode)
- Little or no turbo boost
- Sluggish acceleration
Can you drive with P0045?
With care You can drive, but with less power than normal, so take care when overtaking or joining fast roads. Have it looked at soon.
How to check it
Find the solenoid (usually in the engine bay, with thin vacuum or pressure pipes) and check its connector and pipes. With a scan tool, watch desired and actual boost pressure in live data while accelerating.
How to read and clear P0045 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0045 with this same explanation and whether it’s confirmed, pending or permanent.
With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.
Similar codes
- P0032 Oxygen sensor heater circuit high (bank 1, sensor 1)
- P0036 Oxygen sensor heater circuit fault (bank 1, sensor 2)
- P0037 Oxygen sensor heater circuit low (bank 1, sensor 2)
- P0038 Oxygen sensor heater circuit high (bank 1, sensor 2)
- P0046 Boost control solenoid: range or performance
- P0047 Boost control solenoid: circuit low
- P0048 Boost control solenoid: circuit high
- P0049 Turbocharger or supercharger turbine overspeed
- P0010 Camshaft A actuator control: open circuit (bank 1)
- P0011 Camshaft A timing over-advanced (bank 1)
- P0012 Camshaft A timing over-retarded (bank 1)
- P0013 Camshaft B actuator control: open circuit (bank 1)
P0045 is a generic code, so it means the same on any make, for example on Audi, Fiat, Kia, Mazda, Opel / Vauxhall, Toyota. See what Final OBD does on your car in makes and models.
What does code P0045 mean?
On turbocharged or supercharged engines, an ECU-controlled solenoid sets how much boost is produced, by acting on the wastegate or on the variable geometry vanes. This code means the electrical circuit of that solenoid is open. Without boost control, the engine normally goes into limp mode and cuts power to protect itself.
Can you drive with P0045?
You can drive, but with less power than normal, so take care when overtaking or joining fast roads. Have it looked at soon.
How do you clear P0045?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0045 comes back.
Read it on your car
Final OBD reads the faults of every control unit for free, including each make’s own codes, and with Pro explains each one in plain English. Free clears engine faults at no cost.
Coming soon
Mid to late October 2026
If you want to try it in your car before anyone else, send us your email and we will add you as a tester.
info@finalobd.com