What it means
The control circuit for turbocharger or supercharger boost control A is open or has a malfunction.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Boost Control A is the circuit the control module uses to command the turbocharger or supercharger boost-control actuator or solenoid. The module checks whether that circuit can operate as commanded. P0045 sets when the circuit is open or malfunctioning, such as from a disconnected plug, broken wire, or open solenoid coil.
Common causes
Most likely first.
- Wiring break or unplugged connector
- Solenoid coil open
- Pin pushed back out of connector body
Symptoms
- Check engine light on
- Reduced engine performance
How to diagnose it
- Review freeze-frame data and live boost-related data to note the conditions when Boost Control A stopped responding.
- Inspect the Boost Control A actuator or solenoid connector and its harness for a disconnected plug, damaged wiring, heat exposure, or a backed-out pin.
- Trace the circuit using the vehicle wiring diagram and check its power supply, ground, and control wire for an open.
- Measure the Boost Control A solenoid or actuator circuit as specified by the manufacturer to determine whether its coil or internal circuit is open.
- If wiring and actuator tests pass, verify the module command and feedback using the manufacturer's diagnostic procedure.
Common fixes
- Reconnect the Boost Control A connector if it is unplugged or loose.
- Repair a broken Boost Control A circuit wire or backed-out connector pin.
- Replace the Boost Control A solenoid or actuator if its circuit is confirmed open.
- Repair a verified power, ground, or module-control fault in the Boost Control A circuit.
Can I keep driving?
Reduced power or limp mode may limit acceleration, so avoid overtaking, towing, or entering fast traffic until the boost-control fault is diagnosed. If the engine makes unusual turbo noises, smokes, or loses power sharply, stop safely and arrange assistance.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.