P0249 Turbo wastegate solenoid B signal low

P0249 – OBD-II Trouble Code Technical Description

Turbocharger wastegate solenoid B low signal

What does trouble code P0249 mean?

Trouble code P0249 means “Turbocharger wastegate solenoid B signal low.” This code applies to turbocharged and supercharged vehicles such as Audi, Ford, GM, Mercedes, Mitsubishi, VW and Volvo equipped with an OBD-II system.

The powertrain control module (PCM) controls engine boost pressure by controlling wastegate solenoid B. If the PCM detects a lack of voltage in the solenoid circuit, it sets code P0249. This code indicates an electrical problem and requires diagnosis.

The wastegate solenoid B controls the boost pressure and if it is not working properly can cause problems with engine power and efficiency. Causes may include high solenoid resistance, a short circuit, or wiring problems.

Code P0249 indicates that electrical components need to be checked and the wastegate solenoid B may need to be replaced or wiring repaired to get the engine back to operating condition.

Possible reasons

There are several reasons why your vehicle may display code P0249, but they all have to do with the wastegate solenoid. Common reasons include:

1. Faulty wastegate solenoid, which can result in incorrect voltages.
2. Open or short circuit in the wastegate solenoid circuit.
3. Problems with the electrical connectors inside the wastegate solenoid, such as corrosion, looseness, or disconnection.

The following reasons for setting the P0249 code are also possible:

• Open in the control circuit (ground circuit) between wastegate/boost pressure control solenoid B and the PCM.
• Open in the power supply between wastegate/boost pressure control solenoid B and the PCM.
• Short circuit to ground in the power supply circuit of the boost pressure regulator/waste valve solenoid B.
• The wastegate/boost pressure control solenoid B itself is faulty.
• In the extremely unlikely event, the PCM (powertrain control module) is faulty.

So, the main causes include a faulty solenoid, wiring problems, and problems with the powertrain control module (PCM).

What are the symptoms of trouble code P0249?

When the P0249 code is triggered, you will likely notice a decrease in your engine's ability to accelerate. This may be accompanied by the following symptoms:

1. High-pitched sounds, knocking or whining sounds from the turbocharger or wastegate area when accelerating.
2. Clogged spark plugs.
3. Unusual smoke coming from the exhaust pipe.
4. Whistling sounds from the turbocharger and/or wastegate pipes.
5. Excessive transmission or engine heating.

Additionally, symptoms of a P0249 code may include:

• The malfunction indicator light on the instrument panel comes on.
• A message appears on the instrument panel warning the driver of a malfunction.
• Loss of engine power.

How to diagnose trouble code P0249?

If code P0249 occurs, the following steps should be taken:

1. Check for technical service bulletins (TSBs) for your vehicle make and model. Your problem may already be known to the manufacturer and there is a recommended fix.
2. Locate the wastegate/boost pressure control solenoid "B" on your vehicle and inspect its connectors and wiring. Pay attention to possible damage, corrosion or loose connections.
3. Clean or replace the electrical connectors located inside the wastegate solenoid if corrosion is detected.
4. If you have a scan tool, clear the diagnostic trouble codes and see if the P0249 code returns. If the code is not returned, the problem may be related to the connections.
5. If a P0249 code returns, check the solenoid and related circuits. Typically the wastegate/boost pressure control solenoid has 2 wires. Using a digital volt-ohm meter (DVOM), check the resistance and voltage in the solenoid power circuit.
6. Make sure you have a good ground at the wastegate/boost pressure control solenoid.
7. Test the solenoid with a scan tool to ensure it is functioning properly.
8. If all other tests are successful and the P0249 code continues to appear, the wastegate/boost pressure control solenoid may be faulty. However, do not rule out a faulty PCM before replacing the solenoid.
9. After repairs are completed, you must reboot the system and conduct a test drive to check if the code returns.
10. A mechanic can also check the wastegate port using a handheld vacuum pump connected to the wastegate controller.

Contact a qualified automotive technician if you are still unsure or if the problem persists.

Diagnostic errors

It is important to perform an initial inspection, including inspection of the wastegate solenoid wiring harness and the functionality of the wastegate port and connection, before proceeding with wire removal and repair work. This will eliminate simple problems and avoid unnecessary work that may not be necessary.

If the initial check reveals problems with the bypass valve's wires, port, or connection, these should be considered first when solving the P0249 code.

How serious is trouble code P0249?

Code P0249 is not life-threatening, but it can significantly reduce the performance and power of your turbo engine. Therefore, for many vehicle owners, fixing this problem becomes an important priority in order to return the vehicle to optimal performance.

What repairs will resolve the P0249 code?

Fixing the P0249 code problem can be done by an experienced mechanic in most cases. Here are some of the actions they can take:

1. Replace or repair damaged or broken wires.
2. Solving problems with connectors and contacts.
3. Check the turbocharger boost sensor for faults that could cause an error in the code.
4. Check resistance and voltage values ​​according to production specifications.

After following these steps and fixing the problem, the mechanic can also reset the error code and take it for a test drive to see if the code returns.

What is P0249 Engine Code [Quick Guide]

It is important not to limit yourself to one problem. For example, if a thread is found to be worn, it should be replaced, but other potential problems must also be considered. The error code may be the result of several problems that may need to be resolved at the same time.