What does it mean when an electric vehicle displays 'M' and won't move?
3 Answers
When an electric vehicle displays 'M' and won't move, it indicates a motor malfunction that requires after-sales repair. Below are relevant details about electric vehicles: 1. Types of faults: Electric vehicle faults can be categorized into motor faults, controller faults, battery faults, and charger faults. Motors are divided into brushed and brushless types, with brushed motors gradually being phased out of the market. 2. Diagnosis method: A simple way to check for brushless motor winding abnormalities is to short-circuit the three phase wires (thick yellow, green, and blue wires) of the brushless motor together. Then manually rotate the rear wheel. If there's significant resistance or it won't turn, this indicates the motor is functioning properly.
I encountered the issue of the car not moving when shifted to M gear shortly after driving an electric vehicle, which really worried me at the time. Later, I found out that the battery level had dropped below 15%, and the system automatically limited the output power to protect the battery. After charging for half an hour at a different charging station, it returned to normal. Another time, this happened during heavy rain, and upon inspection, I found that the charging port cover wasn't closed tightly, allowing rainwater to seep in and trigger the short-circuit protection. It's advisable to check the battery percentage on the dashboard before each start; if it's below 20%, charge it immediately. Additionally, during rainy days, remember to check the sealing of the charging port cover and use dust plugs to seal the holes. If none of these are the issue, consider whether the small battery's voltage is insufficient—try charging the 12V battery and then attempt again. If all else fails, it's best to visit a service station to read the fault codes. Nowadays, electric vehicle control systems are very sophisticated, so avoid disassembling them yourself.
When troubleshooting electric vehicles, encountering the issue of the car not moving in M gear is common. Focus on inspecting several key components. First, check the pedal position sensor and use a diagnostic tool to see if the signal feedback is abnormal. Next, test the voltage balance of the battery pack, as an excessive voltage difference in a single cell group can trigger protection. Then, inspect the resolver sensor of the drive motor, as iron debris interfering with the signal can cause the control module to misjudge. Additionally, don't overlook the coolant level, as a malfunction in the thermal management system can also limit output. I recommend keeping a Bluetooth OBD scanner handy to connect to your phone, which can display fault prompts in critical moments. For prevention, avoid frequent sudden acceleration, as overheating and overcurrent can damage the control board. If symptoms are detected, immediately power off and restart. If shifting fails several times in a row, refrain from further attempts.
