OBD-II trouble code
P0045: Turbocharger/Supercharger Boost Control Solenoid Circuit/Open
SAE J2012: boost control solenoid circuit/open. On the 2014 Golf CJAA chart this is the wastegate bypass regulator valve, open, with signal voltage under 4.7 V. That threshold is that diesel section, not every turbo.
Quick facts
- System
- Powertrain
- Category
- Fuel & Air
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $150 – $570 (turbocharger boost-pressure solenoid replacement, parts and labor)
- DIY difficulty
- Intermediate DIY
Browse every code in P0001–P0099, or start from the full code library.
What does P0045 mean?
SAE J2012 APR2002 names P0045 Turbo/Super Charger Boost Control Solenoid Circuit/Open. Section 3.1 says circuit/open is a fixed value or no response, used when a separate high or low detection is not feasible or when it is used beside those codes. P0047 is the low code. P0048 is the high code. P0046 is range/performance. P0045 does not say the turbocharger has failed.
The 2014 Volkswagen Golf, GTI, and Golf R Quick Reference Specification Book (January 2014, NHTSA MC-10122269), engine code CJAA, Fuel and Air Mixture section, puts these on one row: P0045 Wastegate Bypass Regulator Valve Circuit Open, signal voltage less than 4.7 V. CJAA is the 2.0 TDI in that book's table of contents. The 4.7 V figure stays on that row. It is not a gasoline wastegate spec and it is not a Ford ohm spec.
Ford pinpoint HN includes a wastegate regulating-valve solenoid in later steps, and its resistance table lists 14 to 17 ohms for the Edge, Explorer 2.0L, F-150 2.7L, Fiesta 1.0L, Focus 1.0L, and Fusion 1.5L, and 21 to 25 ohms for the other wastegate solenoids in that table. Step HN1 of the copy that was read does not list P0045. Those ohm bands are not a P0045 specification.
RepairPal's diagnosis note for the boost-pressure solenoid says the trouble code tells you which component detected the failure, not which component failed, and that an overboost complaint should include the boost sensor and the MAP sensor before the solenoid is replaced. That is a cost warning, not a P0045 pinpoint.
Common causes
- An open in the boost-control solenoid circuit, the fault section 3.1 names
- On a 2014 Golf with engine code CJAA, wastegate bypass regulator signal voltage under 4.7 V, which that row calls circuit open
- A fuse or a supply that does not reach the solenoid connector
- A connector left off after charge-pipe work
- The Ford 14–17 ohm wastegate band used on a code that pinpoint does not list
- A turbocharger assembly replaced for an open control circuit
Symptoms
- Check engine light with P0045
- Boost that does not follow the command, only after the open circuit is confirmed and the mechanical side is tested
- On the CJAA chart, a regulator signal below 4.7 V
- No overboost and no underboost required by the SAE title
- The low or high code stored instead, when this calibration separates them
- A solenoid that ohms in spec while the signal wire is open
Diagnostic steps
- 1.Open this engine's boost-solenoid circuit test. If the vehicle is a 2014 Golf with engine code CJAA, the specification book calls P0045 wastegate bypass regulator valve circuit open and gives signal voltage under 4.7 V. Do not carry 4.7 V to another engine.
- 2.Ignition off. Find the solenoid the diagram names. Inspect the connector, the fuse, and the hoses if this solenoid is a vacuum valve. Do not condemn the turbo.
- 3.Ignition on, engine off, solenoid unplugged: check the supply the chart names. Ignition off, module disconnected: check the control wire for an open, a short to ground, and a short to power. An open-circuit code does not skip the short checks.
- 4.Measure the coil only against a spec this procedure prints. The Ford HN wastegate bands stay with the DTCs that pinpoint lists, which did not include P0045 in the copy that was read.
- 5.Repair the open the failed step names. Replace the solenoid when the coil is the part that failed its own spec. Repeat the self-test.
- 6.A turbocharger assembly is a later mechanical job. RepairPal's note says to test the system before replacing boost-control parts. It is not the CJAA open-circuit repair.
Repair cost
$150 – $570 (turbocharger boost-pressure solenoid replacement, parts and labor)
RepairPal turbocharger boost-pressure solenoid, updated 3 September 2026. National average $206–$241, labor $75–$111, parts about $130 (repairpal.com/estimator/turbocharger-boost-pressure-solenoid-replacement-cost). Named lines on that page's cost-estimates-by-vehicle list, updated 3 September 2026: Volvo S60 $152–$179, Ford F-150 $164–$193, Lincoln MKZ $176–$210, Mercedes-Benz E350 $285–$336, Chevrolet Trax $305–$339, Volkswagen Beetle $311–$414, Volkswagen Passat $315–$366, and Buick Encore $517–$568. The Chevrolet Trax page for the same solenoid is $305–$339, labor $73–$107, parts about $231. The printed pair rounds the Volvo S60 low end ($152) and the Buick Encore high end ($568). A turbocharger assembly averages $2,631–$3,261 on RepairPal the same day and is outside this pair. The CJAA 4.7 V test can end in a wiring repair, which is also outside the pair.
Estimate your repair
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Open the Repair Cost Estimator with boost control solenoid replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.