The OBD2 code P0045 signifies an issue with the “Turbo Boost Control Solenoid A Circuit Open,” indicating a malfunction in the electrical circuit controlling the turbocharger’s boost solenoid. This problem can affect vehicle performance, often leading to reduced power or a vehicle entering a limp mode to protect the engine. It’s a relatively specific issue that points towards the turbocharger system’s electronic control aspects.
P0045 quick overview
| Meaning | P0045: Turbo Boost Control Solenoid A Circuit Open |
| Is it serious? | Yes, this code can seriously affect vehicle performance and should be addressed promptly. |
| Possible causes | – Faulty turbocharger boost control solenoid – Wiring harness or connector issues – Possible ECM (Engine Control Module) faults |
| How to diagnose? | Check the harness and connector on the turbo boost control solenoid for any signs of damage or corrosion. Perform a load test on all actuator wires and a wiggle test to identify intermittent failures. Inspect the turbocharger assembly for mechanical issues, including the VNT (Variable Nozzle Turbine) and actuator movement. Consider ECM diagnosis only after ruling out wiring and mechanical faults. |
P0045 Meaning
When your car’s computer detects a problem with the Turbo Boost Control Solenoid, it triggers the P0045 code. This part is crucial for managing how much power the turbo adds to your engine. If something’s wrong here, your car might not drive as powerfully as it should, or it might go into “limp mode” to prevent further damage.
The causes can range from a simple loose wire to a need for a new turbo. Mechanics will typically start with the easiest fixes, like checking wires and connections, before moving on to more complex solutions.
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How to fix P0045 – learn from mechanics
I looked into P0045 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: GMC P0045
Vehicle information 2008 GMC W5500 Forward W5S042 5.2L
Issue + repair history
- MIL Lamp on, Limp in mode
- Code P0045 occurring intermittently
- Checked harness & connector on the turbo
- Checked turbo module mounted on the frame rail
- VNT is not seized; actuator on turbo moves VNT
- Relocated module to isolate from shock
Other OBD2 Codes + Test Results
- P0045: Turbo Boost Control Solenoid A Circuit Open
Mechanic suggestions
- Load test all actuator wires and perform a wiggle test
- If all OK, consider replacing turbo assembly with new
- Check for any recalls on turbos by contacting the dealer
Final fix
- After checking wiring harness and finding no issues, problem has not reoccurred
- Possible poor connection resolved
- Customer approved replacement turbo if issue returns
Case #2: Chevrolet P0045
Vehicle information 2004 Chevrolet Silverado 2500 HD 6.6L
Issue + repair history
- MIL Lamp on
- Codes: P0045 (T/C solenoid circuit fault), P0299 (T/C underboost)
- Diagnostics led to consideration of ECM replacement, but deemed unlikely
- Tested T/C solenoid circuit with scan tool and test light, found circuit working properly
- Occasional lack of power reported by customer
- Voltage drop test on turbo circuit showed OK
- Suggested turbo vanes might be sticking due to carbon buildup
Other OBD2 Codes + Test Results
- P0045: T/C solenoid circuit fault
- P0299: T/C underboost
Mechanic suggestions
- Check wiring harness around the driver’s side for chafing, which could cause P0045 DTC
- Repair lower DTCs first before addressing P0299
- Consider replacing fuel filter, as restricted filters can cause various performance issues
- Perform hard test drives, including wide-open throttle runs, to potentially clear the P0299 code
Final fix
- Advised customer to drive the truck harder to activate the turbo, which seemed to keep the MIL light off
- Truck still under warranty, any further issues will be handled by the dealer
Case #3: Chevrolet P0045
Vehicle information 2004 Chevrolet C4500 Kodiak C4C042 6.6L
Issue + repair history
- Lacks power, CEL coming on & off
- Codes: P0045 (turbo boost control solenoid), P0046 (unknown), U0106 (glow plug)
- Replaced turbo and positive solenoid
- Performed T/C relearn per factory specs
- Occasional low power, won’t go over 30 mph
Other OBD2 Codes + Test Results
- P0045: Turbo Boost Control Solenoid
- P0046: Unknown
- U0106: Glow plug
Mechanic suggestions
- Verify vane position sensor on top of turbocharger is reading properly
- Check for any updates for the Duramax engine
- Double-check wiring and perform flow chart diagnostics before replacing turbo
- Check actual boost and inspect for CAC leaks, especially around plastic tubes near A/C line
Final fix
- Lack of power traced to accidentally flipping the PTO switch
- No further issues after resolving the switch error
How to diagnose P0045
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Explanation |
|---|---|
| Check the wiring harness and connector | Inspect for damage or corrosion that could interrupt the solenoid’s electrical circuit. |
| Load test actuator wires and perform wiggle test | Identify intermittent electrical faults by testing wire integrity under stress and movement. |
| Inspect the turbocharger assembly | Look for mechanical issues that could prevent proper turbo operation, like stuck VNT or actuator. |
| Consider ECM diagnosis | Proceed with evaluating the engine’s computer if other diagnostics don’t resolve the issue. |
| Check for recalls and software updates | Contact the dealer for potential recalls on turbos or updates for the Duramax engine that could fix the issue. |
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko