P135B Code BMW: Meaning, Causes, Symptoms and Fixes

BMW P135B Code:Knock Sensor Signal 2 Signal Implausible

As a car owner, it’s always frustrating to see a warning light pop up on your dashboard. One of the most common issues that BMW drivers face is the P135B code, which indicates a problem with the knock sensor signal. If you’re experiencing this issue, it’s important to understand what it means and how to fix it. In this article, we’ll dive into the meaning, causes, symptoms, and fixes for the BMW P135B code, so you can get back on the road with confidence.

What Does the BMW P135B Code Mean?

The BMW P135B code is a diagnostic trouble code (DTC) that indicates an issue with the knock sensor signal 2 in BMW vehicles. This code is triggered when the engine control module (ECM) detects an implausible signal from the knock sensor 2. The knock sensor is responsible for detecting engine knock or detonation, which can cause damage to the engine if left unchecked. When the ECM receives an implausible signal from the knock sensor 2, it may cause the engine to run poorly or even stall. It is important to address this issue promptly to prevent further damage to the engine.

Signs and Symptoms of BMW P135B Code

The BMW P135B code is a diagnostic trouble code (DTC) that indicates a problem with the knock sensor signal 2 in BMW vehicles. This code is usually accompanied by a check engine light on the dashboard. Here are some of the signs and symptoms that may indicate the presence of the P135B code:

  • Engine Misfires: One of the most common symptoms of the P135B code is engine misfires. This occurs when the engine’s cylinders do not fire properly, causing a loss of power and a rough idle.
  • Reduced Engine Performance: Another symptom of the P135B code is reduced engine performance. This can manifest as a lack of power, slower acceleration, and reduced fuel efficiency.
  • Knocking or Pinging Sounds: The knock sensor is responsible for detecting engine knock or ping, which can cause damage to the engine. If the knock sensor signal is implausible, it may result in knocking or pinging sounds coming from the engine.
  • Increased Emissions: A faulty knock sensor can also cause an increase in emissions, which can lead to a failed emissions test.
  • Stalling: In some cases, the P135B code can cause the engine to stall or shut off completely. This can be dangerous if it happens while driving.

If you experience any of these symptoms, it is important to have your BMW vehicle inspected by a qualified mechanic as soon as possible. Ignoring the P135B code can lead to further damage to the engine and other components, resulting in costly repairs.

Possible Causes of BMW P135B Code

The BMW P135B code is a diagnostic trouble code (DTC) that indicates an issue with the knock sensor signal 2 signal implausible. This code is usually triggered when the engine control module (ECM) detects a problem with the knock sensor circuit. Here are some of the possible causes of the BMW P135B code:

  • Failed knock sensor: The knock sensor is responsible for detecting engine knock or detonation. If the sensor fails, it can cause the ECM to trigger the P135B code.
  • Wiring issues: Faulty wiring or a damaged connector in the knock sensor circuit can cause the P135B code to appear.
  • Failed ECM: In rare cases, a failed ECM can cause the P135B code to appear.
  • Engine mechanical problems: Issues with the engine, such as a damaged piston or a worn-out bearing, can cause engine knock or detonation, which can trigger the P135B code.
  • Incorrect fuel octane: Using fuel with an incorrect octane rating can cause engine knock or detonation, which can trigger the P135B code.
  • Failed ignition system: A faulty ignition system, such as a failed spark plug or ignition coil, can cause engine knock or detonation, which can trigger the P135B code.

It is important to note that the P135B code can be caused by a combination of these factors. Therefore, it is recommended to have a professional mechanic diagnose and repair the issue to ensure that all underlying problems are addressed. Ignoring the P135B code can lead to further engine damage and potentially costly repairs.

Fixes for BMW P135B Code

The BMW P135B code indicates an issue with the knock sensor signal 2, which is responsible for detecting engine knock or detonation. If left unaddressed, this issue can lead to engine damage and reduced performance. Here are some potential fixes for the P135B code:

1. Check the knock sensor wiring: The first step in fixing the P135B code is to inspect the wiring and connections for the knock sensor. Look for any signs of damage, corrosion, or loose connections. If any issues are found, repair or replace the wiring as needed.

2. Replace the knock sensor: If the wiring and connections are in good condition, the next step is to replace the knock sensor itself. This is a relatively simple process that involves removing the old sensor and installing a new one. Be sure to use a high-quality replacement sensor to ensure proper function.

3. Check for engine damage: In some cases, the P135B code may be caused by actual engine damage rather than a faulty sensor or wiring. If this is the case, a more extensive repair may be necessary. A mechanic can perform a thorough inspection of the engine to determine if any damage is present.

4. Reset the engine control module: After making any repairs or replacements, it’s important to reset the engine control module (ECM) to clear the P135B code. This can be done using a diagnostic tool or by disconnecting the battery for a few minutes.

5. Perform a test drive: Once the repairs are complete and the ECM has been reset, take the vehicle for a test drive to ensure that the P135B code does not reappear. If it does, further diagnosis may be necessary.

In summary, the fixes for the BMW P135B code involve checking the knock sensor wiring, replacing the sensor if necessary, checking for engine damage, resetting the ECM, and performing a test drive. It’s important to address this issue promptly to prevent further damage to the engine. If you’re not comfortable performing these repairs yourself, it’s best to take your vehicle to a qualified mechanic for diagnosis and repair.

How Much Will It Take to Fix the BMW P135B Code?

The cost of fixing the BMW P135B code will depend on the underlying cause of the issue. The P135B code indicates that there is an implausible signal from the knock sensor 2 in the engine. This can be caused by a faulty knock sensor, damaged wiring, or a problem with the engine control module (ECM).

The first step in fixing the issue is to diagnose the root cause of the problem. This may involve using diagnostic tools to check the knock sensor and wiring for any faults. If the knock sensor is found to be faulty, it will need to be replaced. The cost of a new knock sensor can range from $50 to $200, depending on the make and model of the vehicle.

If the wiring is damaged, it may need to be repaired or replaced. This can cost anywhere from $100 to $500, depending on the extent of the damage and the complexity of the repair. If the issue is with the ECM, it may need to be reprogrammed or replaced, which can cost upwards of $1,000.

In summary, the cost of fixing the BMW P135B code can vary widely depending on the underlying cause of the issue. It is best to consult with a qualified mechanic to diagnose and fix the problem.

Possible Causes and Fixes of Code

Possible Cause Fix Cost to Fix
Failed knock sensor Replace knock sensor $100-$300
Wiring issues in knock sensor circuit Repair or replace wiring $100-$500
Failed engine control module (ECM) Replace ECM $500-$1000
Engine mechanical issues Repair engine mechanical issues Varies depending on issue

 

Preventing the BMW P135B Code

The BMW P135B code is a knock sensor signal 2 signal implausible error that can cause a variety of issues in your vehicle. To prevent this code from appearing, there are several preventive measures you can take. Here are some of the most effective ways to prevent the BMW P135B code:

1. Regular Maintenance: One of the most important preventive measures you can take is to ensure that your vehicle undergoes regular maintenance. This includes regular oil changes, tune-ups, and inspections. Regular maintenance can help prevent issues that can lead to the P135B code.

2. Use High-Quality Fuel: Using high-quality fuel can help prevent the P135B code from appearing. Low-quality fuel can cause engine knock, which can trigger the code. Using high-quality fuel can help prevent engine knock and keep your vehicle running smoothly.

3. Check the Knock Sensor: The knock sensor is responsible for detecting engine knock and sending a signal to the engine control module (ECM). If the knock sensor is faulty, it can trigger the P135B code. Regularly checking the knock sensor can help prevent this issue.

4. Check the Wiring: Faulty wiring can also cause the P135B code to appear. Regularly checking the wiring can help prevent this issue. Look for any signs of damage or wear and replace any damaged wiring as soon as possible.

5. Use the Right Oil: Using the right oil can also help prevent the P135B code from appearing. Make sure to use the oil recommended by the manufacturer and change it regularly. Using the wrong oil or not changing it regularly can cause engine knock, which can trigger the code.

How Serious is the BMW P135B Code?

The BMW P135B code is a diagnostic trouble code that indicates a problem with the knock sensor signal 2 in BMW vehicles. This code is considered to be moderately serious as it can affect the performance and efficiency of the engine. The knock sensor is responsible for detecting any unusual vibrations or noises in the engine and sending a signal to the engine control module (ECM) to adjust the ignition timing accordingly.

If the knock sensor signal 2 is implausible, it means that the ECM is receiving a signal that is outside of the expected range. This can cause the engine to run poorly, misfire, or even stall. In addition, it can also lead to increased fuel consumption, reduced power, and increased emissions. Therefore, it is important to address the P135B code as soon as possible to prevent any further damage to the engine.

The causes of the P135B code can vary, but some common culprits include a faulty knock sensor, damaged wiring or connectors, or a malfunctioning ECM. To diagnose and fix the issue, it is recommended to take the vehicle to a certified mechanic or dealership for proper inspection and repair.

Can You Still Drive with the BMW P135B Code?

If your BMW has triggered the P135B code, you may be wondering if it is safe to continue driving your vehicle. The answer to this question depends on the severity of the issue and the symptoms you are experiencing.

In some cases, the P135B code may not cause any noticeable symptoms, and you may be able to continue driving your BMW without any issues. However, it is important to note that ignoring the code can lead to more severe problems down the line.

If you are experiencing symptoms such as engine misfires, reduced power, or poor fuel economy, it is not recommended to continue driving your BMW. These symptoms can indicate a more serious issue that requires immediate attention.

It is always best to have your BMW diagnosed by a professional mechanic as soon as possible to determine the root cause of the P135B code and any associated symptoms. This will ensure that your vehicle is safe to drive and prevent any further damage to your engine.

Conclusion

If you are experiencing the BMW P135B code, it is important to address the issue promptly to avoid further damage to your vehicle. The code indicates an implausible signal from the knock sensor 2, which can lead to engine performance issues and potential engine damage. The causes of the code can range from faulty sensors to wiring issues, and it is recommended to have a professional diagnose and repair the issue. Ignoring the code can lead to more costly repairs down the line. By addressing the issue promptly, you can ensure the longevity and reliability of your BMW vehicle.

 

FAQ

What does the BMW P135B code mean?

The BMW P135B code is a diagnostic trouble code (DTC) that indicates an implausible signal from the knock sensor 2 in the engine. This means that the signal being sent to the engine control module (ECM) is not within the expected range, which can cause engine performance issues.

What are the symptoms of the BMW P135B code?

The symptoms of the BMW P135B code may include engine misfires, reduced power and acceleration, rough idling, and increased fuel consumption. In some cases, the check engine light may also be illuminated.

What are the common causes of the BMW P135B code?

The common causes of the BMW P135B code include a faulty knock sensor, damaged wiring or connectors in the knock sensor circuit, a malfunctioning ECM, or engine mechanical problems such as a damaged piston or cylinder.

How is the BMW P135B code diagnosed?

The BMW P135B code can be diagnosed using an OBD-II scanner, which will read the code and provide information on the knock sensor signal. A mechanic may also perform a visual inspection of the knock sensor and its wiring, as well as conduct a test drive to observe engine performance.

Can I still drive my BMW with the P135B code?

It is not recommended to drive your BMW with the P135B code, as it can cause engine damage and reduce performance. It is best to have the issue diagnosed and repaired as soon as possible.

How is the BMW P135B code fixed?

The BMW P135B code can be fixed by replacing the faulty knock sensor, repairing any damaged wiring or connectors in the knock sensor circuit, or replacing the ECM if necessary. In some cases, engine mechanical problems may need to be addressed as well.

Can I fix the BMW P135B code myself?

While it is possible to diagnose the BMW P135B code yourself using an OBD-II scanner, it is not recommended to attempt to fix the issue yourself unless you have experience with engine repairs. It is best to have a qualified mechanic diagnose and repair the issue.

Learn about other similar BMW Fault Codes from our BMW OBD 2 Fault Code List.

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