P0045 code meaning
Turbocharger/Supercharger Boost Control A Circuit/Open
Powertrain system Generic code P00xx codes Check engine light
What P0045 means
"Boost control A" is the electrically driven actuator the engine control module uses to set boost pressure: depending on the engine a pulse-width modulated solenoid or vacuum converter at the wastegate, the control valve of variable turbine vanes, or an electric actuator with position feedback. The letters A and B denote two separate actuators, for example on the low- and high-pressure turbocharger of a two-stage system, not the cylinder banks. This code is set when the control circuit is open: with the driver switched off no load can be measured, or the measured state does not match the command. Without control the actuator usually falls back to its rest position, which on most engines means low boost; depending on the design too much boost is also possible.
P0045 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0045
- Check engine light on
- Loss of power or reduced power mode
- Weak acceleration, noticeable turbo lag
- Overboost possible in rare cases
Common causes of P0045
- Most likelyConnector at the actuator corroded or loose
- Most likelyWire broken or chafed through
- PossibleSolenoid coil in the actuator burnt out
- PossibleFuse or ignition supply faulty
- Less likelyEngine control module or separate actuator control unit faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Boost control actuator aBoost control actuator wiringEngine control module
What each part of P0045 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| 45 | The exact fault in that area. |
What to do next
- Note P0045 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0045
What does P0045 mean?
P0045 means "Turbocharger/Supercharger Boost Control A Circuit/Open". "Boost control A" is the electrically driven actuator the engine control module uses to set boost pressure: depending on the engine a pulse-width modulated solenoid or vacuum converter at the wastegate, the control valve of variable turbine vanes, or an electric actuator with position feedback. It is a generic code, so it means the same on every make.
Is it safe to drive with P0045?
Drive gently and only to a workshop. With P0045 the car can go into limp mode (reduced power) to protect itself.
Will P0045 fail an emissions test?
Yes, it can. P0045 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0045 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0045 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.