Problems Mini Cooper

The Mini Cooper is a beloved compact car known for its style and performance. However, like any vehicle, it can experience problems that leave owners scratching their heads. In this article, we will delve into a Mini Cooper owner’s forum discussion to explore a specific issue and potential solutions.

Mysterious Engine and Electrical Issues

One Mini Cooper owner shared their frustrating experience of owning a Mini Cooper S for 12 weeks, with seven of those weeks spent dealing with an elusive issue. The car had a recurring problem that manifested as follows:

• Battery Light: Upon starting the car on one occasion, the battery light came on.
• Engine Management Light (EML): After a brief drive, the EML light illuminated, followed by the car entering limp mode.
• Melting Plastic Smell: While in limp mode, the owner noticed a melting plastic smell and observed a bit of smoke emanating from the passenger side vent area.
• Intermittent Issues: The issue seemed to occur intermittently, with no apparent pattern. Sometimes the car ran fine, while other times, it entered limp mode with warning lights.

Multiple garages and an auto electrician were unable to pinpoint the problem. Various components, including the alternator and the ECU, were replaced, but the issue persisted. The car was even taken to a tuning specialist with no success.

Possible Solutions and Troubleshooting

1. Power Relay Check: One forum member suggested checking if a power relay was providing power to the Engine Control Unit (ECU). They shared a similar experience with their Audi, where a faulty power relay caused intermittent issues and prevented communication with the ECU. In their case, the car ran normally when the relay worked, but when it failed, the car wouldn’t start, and communication with the ECU was lost.

2. Overload or Short Circuit: Another member suggested that a hidden short circuit or overload in the wiring loom might be blocking communication with the ECU. Overloads or shorts can generate heat and smoke without necessarily causing ignition. Thoroughly inspecting the wiring loom for signs of chafing, damage, or melting is essential.

3. Can Bus and Module Communication: Investigating the Mini Cooper’s Controller Area Network (CAN Bus) and its various control modules might yield clues. The car has multiple CAN buses for different functions, and a gateway box enables communication between them. Understanding how these CAN buses work and which one connects to the engine ECU could provide insights into the issue.

4. Direct ECU CAN Connection: If the ECU’s CAN connections cannot be established through the OBD port, attempting a direct connection to the ECU’s CAN network might be an option. This would involve identifying the correct wires and creating a dummy OBD port specifically for ECU communication.

While these suggestions offer potential avenues for investigation, diagnosing complex electrical issues in a vehicle can be challenging. In such cases, it’s often advisable to consult with experienced auto electricians or specialist mechanics who have expertise in Mini Cooper diagnostics. By working methodically and eliminating possible causes, it’s possible to uncover and resolve even the most elusive car problems.