The turbo solenoid valve is a pneumatic and electrical component responsible for controlling the turbocharger. If it fails, it can cause turbo malfunctions. However, replacing the turbo solenoid valve is relatively easy if you know where to find it in your engine compartment.
How does the Turbo Solenoid Valve work?
The turbocharger, or simply turbo, is designed to increase the power of your engine. It consists of interconnected blades and is located at the engine’s exhaust outlet. When the engine expels exhaust gases, they spin one of the turbo’s blades, while the other compresses air, increasing the combustion chamber’s pressure.
In essence, the turbo is a turbine that compresses air to improve engine combustion, hence its name. To achieve this, it utilizes a wastegate, which is a valve that limits exhaust gas pressure by diverting it if necessary.
The turbo solenoid valve is responsible for controlling the wastegate. It is controlled by the engine control unit. This valve consists of an electromagnetic coil and an air valve. The turbo solenoid valve has two functions:
- Pneumatic: to control the wastegate.
- Electrical: to create an electromagnetic field by sending an impulse to the coil, opening the pneumatic circuit.
Where is the Turbo Solenoid Valve located?
The location of the turbo solenoid valve depends on your car model. However, it is always found near the turbocharger, which is located at the exhaust outlet under your hood. It is a small plastic block connected to the engine and turbo with electrical cables. Typically, you will find the turbo solenoid valve on the driver’s side, near the windshield.
What are the symptoms of a faulty Turbo Solenoid Valve?
A malfunctioning turbo solenoid valve can result from issues with either its pneumatic or electrical functions. Pneumatic failure usually stems from problems with the vacuum pump, hoses, or a punctured valve diaphragm.
Regarding the electrical circuit, a malfunction can be caused by power supply issues to the turbo solenoid valve, engine control unit malfunctions, or problems with the wiring harness.
A faulty turbo solenoid valve can exhibit the following symptoms:
- Loss of power: the most common symptom of turbo failure.
- Whistling sound during acceleration.
- Blue smoke from the exhaust.
- Smell of burning oil.
- Noisy turbo solenoid valve.
Differentiating the symptoms of a faulty solenoid valve from those of a wastegate or turbine failure can be challenging. Therefore, a turbo diagnosis is necessary, specifically testing the solenoid valve.
How to test a Turbo Solenoid Valve?
To test your turbo solenoid valve, you need to check both its pneumatic and electrical functions. This requires performing several tests:
- Pneumatic pump test.
- Solenoid valve outlet test.
- Opening and closing test of the solenoid valve.
- Electrical resistance test.
To conduct these tests, you’ll need 6 mm and 8 mm connectors, a diagnostic tool, an ohmmeter or multimeter, and a vacuum gauge. Use the vacuum gauge on the air pump hose and start the engine: the vacuum should be achieved within one second. When accelerating, the vacuum should reach its maximum. Stop the engine, and the vacuum should remain the same for a few minutes.
Next, disconnect the air hose and use the vacuum gauge to repeat the test described above. Once again, the vacuum should be achieved within one second, and the needle should not immediately return to zero when the engine is turned off.
Proceed with the opening and closing ratio test of the turbo solenoid valve. Use a diagnostic tool, first at cold idle and then while accelerating. At idle, the normal opening ratio should be 85%, and during acceleration, it should range between 35% and 48%.
Conclude with an electrical test, which can replace the ratio test if you don’t have a diagnostic tool. Using an ohmmeter or multimeter, measure the resistance. An infinite measurement indicates a faulty turbo solenoid valve.
How to replace the Turbo Solenoid Valve?
Replacing your turbo solenoid valve is relatively straightforward. Simply disconnect the electrical connection, three hoses, and its bracket. Accessing the valve is also relatively easy, but make sure to purchase a compatible part for your engine.
Tools Required:
- Toolbox
- Jack
- Jack stands
- Turbo solenoid valve
Step 1: Lift the vehicle
Use a jack to lift your vehicle and secure it with jack stands placed at designated points. Consult your owner’s manual to ensure proper stabilization. Engage the parking brake and block the rear wheels.
Step 2: Remove the turbo solenoid valve
Remove the plastic engine cover if present, then locate the turbo solenoid valve. It can be identified by the electrical cable connecting it to the engine and turbo. It is a plastic housing located near the turbo, which is positioned at the exhaust outlet of the engine.
Disconnect the hoses and electrical connector of the solenoid valve. Remove the two nuts to detach it. You need to disconnect the air inlet, the turbo itself, and the vacuum pump.
Step 3: Install the new Turbo Solenoid Valve
After ensuring that the new turbo solenoid valve is compatible with your vehicle, you can proceed with the installation. Reconnect the electrical connector and hoses, including the air inlet, turbo, and vacuum pump. Once the turbo solenoid valve is reconnected, replace the engine cover, lower your vehicle, and test to ensure everything is functioning correctly.
What is the price of a Turbo Solenoid Valve?
The price of a turbo solenoid valve alone ranges from approximately $20 to $60, depending on the brand and where you purchase it (dealer, parts supplier, etc.). To have the part replaced by a professional mechanic, you’ll need to factor in the cost of labor, which averages around $60. In total, the price of replacing a turbo solenoid valve ranges from $100 to $200.
Now you have a comprehensive understanding of the role and functioning of the turbo solenoid valve. As you have learned, it is one of the potential causes of turbocharger failure. Therefore, it is crucial to test the solenoid valve to ensure it is responsible for the issue. In such cases, it is possible to replace the solenoid valve without replacing the entire turbocharger.
