P0045
Fix within a few daysThe engine computer has detected an open circuit in the turbocharger or supercharger boost control solenoid.
Code P0045 means your engine computer detected an open circuit in the turbo/supercharger boost control solenoid. Common causes: faulty solenoid (70%), wiring issues (25%). Drivability: Limit driving, fix within a few days. Repair cost: $50-$250 DIY, $150-$550 professional.
Can I Drive With P0045?
Limit driving, fix within a few days
Essential trips under 10 miles, avoid highways and heavy acceleration. Do not drive if the vehicle is in 'limp mode' or has significant power loss.
Stop driving immediately if: Vehicle enters limp mode, significant power loss, loud noises from the engine/turbo, burning smell.
Symptoms of P0045
- 1Reduced engine power or 'limp mode'
- 2Check Engine Light is on
- 3Poor acceleration
- 4Engine may make whistling or hissing noises (if boost is leaking or unregulated)
Common Causes of P0045
Parts most likely causing this code, ranked by probability
The solenoid itself has an internal electrical fault, preventing it from regulating boost pressure.
70% of P0045 cases are fixed by replacing this part
Damaged, corroded, or disconnected wires or connectors create an open circuit to the boost control solenoid.
25% of P0045 cases are fixed by repairing the wiring
A rare internal fault within the engine computer prevents it from properly controlling the boost solenoid circuit.
5% of P0045 cases are fixed by replacing the ECM/PCM
Check These First (Before Buying Parts)
- Visually inspect the boost control solenoid's electrical connector and wiring for any signs of damage, corrosion, or loose connections.
- Ensure all vacuum lines (if applicable to your system) connected to the boost control solenoid are intact and not cracked or disconnected.
How to Diagnose P0045
- 1Visually inspect the boost control solenoid and its wiring harness for any obvious damage, corrosion, or loose connections.
- 2Using a multimeter, check for continuity and resistance across the boost control solenoid's terminals. Compare to factory specifications.
- 3Check for proper voltage supply and ground at the boost control solenoid connector with the ignition on.
- 4If possible, use a scan tool with bidirectional control to actuate the boost control solenoid and listen for a click or observe its operation.
P0045 on Popular Vehicles
Ford F-150
2011-2024EcoBoost engines are prone to boost control solenoid failures due to heat. Inspect the wiring harness carefully for damage near the turbochargers.
75% fixed by replacing the solenoid or repairing wiring
Subaru WRX/STI
2002-2024Subaru's boost control solenoids (often called 'boost control valve' or 'wastegate solenoid') can fail, leading to P0045. Check vacuum lines connected to the solenoid for cracks or leaks, though the code is electrical.
70% fixed by replacing the solenoid
Volkswagen/Audi
2006-2024On 1.8T and 2.0T engines, the N75 valve (boost pressure control valve) is a common culprit for P0045. Its electrical connector and wiring are also susceptible to damage.
70% fixed by replacing the N75 valve
Frequently Asked Questions
What does P0045 mean?
P0045 indicates that your vehicle's engine computer has detected an open circuit in the electrical system controlling the turbocharger or supercharger boost control solenoid. This solenoid is responsible for regulating the boost pressure your engine produces.
Can I drive with P0045?
Limit driving, fix within a few days. Driving with this code means your engine is likely operating with reduced power or in 'limp mode' to prevent damage. Continued driving, especially with heavy acceleration, can potentially cause further damage to the turbocharger or engine components due to uncontrolled boost.
Will P0045 clear itself?
No, P0045 will not clear itself. An open circuit is a hard fault that requires diagnosis and repair. The Check Engine Light will remain on until the underlying electrical issue with the boost control solenoid circuit is resolved.
How do I fix P0045 myself?
Start by visually inspecting the boost control solenoid and its wiring for damage. If the wiring looks good, you will need a multimeter to test the resistance of the solenoid and check for proper voltage at its connector. If the solenoid tests bad, replacing it is the most common fix. If the wiring is damaged, repair it.
How much does it cost to fix P0045?
The cost to fix P0045 varies. DIY repair, primarily replacing the boost control solenoid, typically costs $50-$250 for the part. Professional repair at a shop will cost $150-$550, which includes parts and labor.
P0045 keeps coming back - why?
If P0045 keeps returning, it means the initial repair did not address the root cause. Common reasons for recurrence include: a faulty replacement solenoid, an intermittent wiring issue that was missed, or a rare problem with the engine computer itself.
Will P0045 fail emissions/smog test?
Yes, P0045 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on automatically results in a failure in most states, and an issue with boost control can also affect exhaust gas composition.
What's the difference between P0045 and P0046?
P0045 indicates an 'open circuit' in the boost control solenoid, meaning there's a complete break in the electrical path. P0046 indicates a 'range/performance problem' with the circuit, meaning the signal is present but not within the expected operating parameters (e.g., too high or too low resistance).
P0045 on Ford F-150 EcoBoost
On Ford F-150 EcoBoost engines, P0045 often points to a faulty turbocharger boost control solenoid (wastegate solenoid). These solenoids can fail over time due to heat and vibration. Always check the wiring harness for chafing or corrosion, especially near the turbocharger.
Questions to Ask Your Mechanic
Did you check the resistance of the boost control solenoid and compare it to factory specifications?
Good answer: Yes, I measured the resistance at [X ohms] and it was outside the specified range of [Y-Z ohms], indicating an internal fault with the solenoid.
What did you find when inspecting the wiring harness and connector for the boost control solenoid?
Good answer: I found corrosion on pin 2 of the connector, which was causing an open circuit. I cleaned and repaired the connector, and the code has not returned.
Repair Cost Estimate
DIY Repair
Parts only
$50-$250
Shop Repair
Parts + labor
$150-$550
Save $100-$300 by doing it yourself
Difficulty
intermediate
Time
1-3 hours
Intermediate - requires basic electrical diagnostic skills and tools like a multimeter, along with the ability to access the boost control solenoid, which can be challenging on some vehicles.
Cost of Waiting
Ignoring P0045 can lead to continued reduced engine power and potentially force your vehicle into 'limp mode.' If the boost control system is completely unregulated, it could lead to turbocharger overspeed or engine damage from incorrect boost pressure. A $50-$250 solenoid replacement now prevents a much more expensive turbocharger replacement ($1,000-$3,000) or engine repair later.
Tools You'll Need
- OBD-II scan tool
- Multimeter
- Socket set
- Wrench set
- Wire strippers/crimpers (if wiring repair is needed)
- Electrical tape or heat shrink tubing
P0045 is a common code on turbocharged or supercharged vehicles. The repair is usually straightforward, often involving replacing a single solenoid, and your engine will regain its full power afterward.
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Your Next Steps
Step 1: Perform a thorough visual inspection of the boost control solenoid's wiring harness and connector. Look for any frayed wires, bent pins, or corrosion. Ensure the connector is fully seated.
Step 2: If the visual inspection does not reveal any issues, use a multimeter to test the resistance of the boost control solenoid. Compare your reading to the manufacturer's specifications. Also, check for proper voltage and ground at the solenoid's connector.
Step 3: If the solenoid tests faulty or the wiring is damaged, you will likely need to replace the boost control solenoid or repair the wiring. Parts you'll likely need: a new boost control solenoid.