The BMW E90 is known for its luxurious driving experience‚ but its complex electronics can sometimes cause frustrating issues. One common problem that can leave you stranded is a transmission flash failure‚ which prevents the car from starting. This article will guide you through the potential causes and troubleshooting steps for this issue.
Understanding the Issue
When you encounter a transmission flash failure‚ the car’s dashboard will typically display a “transmission malfunction” message. The car may also refuse to start‚ or it may start but immediately shut down. This problem often arises due to a communication error between the transmission control module (TCM) and other electronic systems.
Common Causes
Several factors can contribute to transmission flash failures in the BMW E90⁚
- Faulty Transmission Control Module (TCM)⁚ The TCM is the brain of the transmission‚ and a faulty TCM can disrupt communication and cause the car to fail to start.
- Battery Issues⁚ A weak or dying battery can disrupt the power supply to the TCM‚ leading to communication problems.
- Loose or Damaged Electrical Connections⁚ Faulty wiring or loose connections within the transmission system can interrupt the flow of information.
- Faulty Sensors⁚ Various sensors‚ such as the transmission fluid temperature sensor or the vehicle speed sensor‚ can malfunction and send incorrect signals to the TCM.
- Software Glitch⁚ Occasionally‚ software glitches in the TCM can cause communication errors.
Troubleshooting Steps
Before taking your BMW E90 to a mechanic‚ try these troubleshooting steps⁚
- Check the Battery⁚ Ensure the battery terminals are clean and tight. If the battery is weak‚ replace it.
- Inspect Electrical Connections⁚ Visually inspect the wiring harness and connections for any signs of damage or looseness. Pay attention to the connectors to and from the TCM.
- Scan for Error Codes⁚ Use an OBD2 scanner to read any error codes stored in the TCM. These codes can provide valuable clues about the problem.
- Reset the TCM⁚ Disconnect the battery for several minutes to allow the TCM to reset. This may resolve temporary software glitches.
- Professional Diagnosis⁚ If the issue persists‚ consult a reputable BMW mechanic for a professional diagnosis. They can use specialized tools to test the TCM and other components.
Important Considerations
Remember‚ attempting repairs on a complex system like the BMW E90’s transmission can be dangerous. Always consult a qualified mechanic if you’re unsure about any procedures.
By understanding the common causes and following these troubleshooting steps‚ you can increase your chances of identifying and resolving a transmission flash failure in your BMW E90. Early detection and proper maintenance can help prevent this issue and ensure a smooth and enjoyable driving experience.