What Does P0045 Mean?
The PCM has detected an open circuit or malfunction in the turbocharger/supercharger boost control solenoid 'A' circuit. This solenoid (also called a wastegate control solenoid or boost control valve) regulates boost pressure by controlling the wastegate or bypass valve. The driver will likely notice reduced power, a loss of turbo boost, or the engine going into a reduced-power limp mode.
Common Causes
35%
Failed or stuck boost control solenoid (internal coil open or valve jammed)
30%
Broken, disconnected, or corroded wiring/connector to the boost control solenoid
20%
Cracked, split, or disconnected vacuum/boost hoses to the wastegate actuator
15%
PCM driver circuit failure for the boost control solenoid output
Diagnostic Steps
1
Monitor live data for actual boost pressure vs. commanded boost — confirm the system is not reaching target boost pressure to correlate with the circuit fault.
2
Locate the boost control solenoid (typically mounted on the intake manifold or near the turbo). Disconnect the electrical connector and measure the solenoid coil resistance — expect 10–30 ohms depending on application. Infinite resistance = open coil.
3
With the solenoid disconnected, verify battery voltage (12V+) on the power supply wire with KOEO. Check the ground/control wire for continuity back to the PCM (less than 1 ohm).
4
Inspect the electrical connector for corrosion, bent pins, or water intrusion. Check the harness routing for heat damage near the turbo and exhaust.
5
Inspect the vacuum/pressure lines from the solenoid to the wastegate actuator for cracks, kinks, or disconnection. Apply vacuum to the actuator directly to confirm it moves freely.
6
If electrical and mechanical tests pass, command the solenoid on/off using a bi-directional scan tool and listen/feel for solenoid click and actuator movement.
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
The PCM has detected an open circuit or malfunction in the turbocharger/supercharger boost control solenoid 'A' circuit. This solenoid (also called a wastegate control solenoid or boost control valve) regulates boost pressure by controlling the wastegate or bypass valve. The driver will likely notic...
The most common cause of P0045 (Turbocharger/Supercharger Boost Control "A" Circuit/Open) is: Failed or stuck boost control solenoid (internal coil open or valve jammed)
Typical repair costs for P0045 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Drive with caution. Loss of boost control can result in either no boost (reduced power, dangerous for highway merging) or in rare cases uncontrolled overboosting which can cause engine damage. If you notice excessive boost or unusual turbo noise, stop driving immediately. Limp mode is usually safe for short distances.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0045 to identify the root cause.
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Quick Info
Category
Powertrain
System
Forced Induction / Turbocharger
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
