What Causes an Automatic Transmission Car to Suddenly Stop Moving When Reversing?
3 Answers
There are several possible reasons why an automatic transmission car may stop moving when reversing: Accidental Activation of the Auto Hold Function: This feature enhances safety when waiting at traffic lights or crossing pedestrian crossings by preventing the car from moving without pressing the accelerator. Once the auto hold function is deactivated, releasing the brake will allow the car to move forward or reverse. Electronic Parking Brake Not Released or Improper Gear Engagement: If the electronic parking brake is not released or the gear is not properly engaged, the reverse gear may not function. Releasing the electronic parking brake and adjusting the gear engagement method can resolve this issue. Transmission Problems: Internal transmission faults may occur. First, check if the transmission fluid level is too low and whether the main oil pressure and gear oil pressure are normal. Then, verify if the gear switch signal is normal, if the wiring from the transmission computer to the shift solenoid valve is intact, and if the gear solenoid valve is functioning properly. If all these components are in order, it indicates an issue with the internal control system of the transmission, requiring disassembly to inspect the internal actuators.
Last time I encountered a situation where the car suddenly stopped while reversing. I was just about to back out of the parking space when the car seemed to be nailed to the ground. Common causes for this issue include transmission problems, such as hydraulic control unit failure leading to power transmission interruption, or slipping of the reverse clutch. Additionally, electronic gear sensors can occasionally have poor contact, showing that the R gear is engaged when it actually isn't. Another possibility is low or severely deteriorated transmission fluid levels, which is particularly common in older vehicles. In my case, the final inspection revealed that the gear shift cable was loose, causing incomplete gear engagement. I recommend repeatedly pressing the brake pedal and then trying to shift gears again. If multiple attempts fail, you should immediately turn off the engine to prevent complete transmission failure—never force it.
Our auto repair shop frequently deals with issues of automatic transmission reverse gear failure, which can stem from several common factors. On the mechanical side, it's essential to check whether the reverse gear set in the transmission is jammed or if the torque converter's lock-up mechanism has failed. For the electronic control system, focus on inspecting whether the shift solenoid valve is open-circuited or if the transmission control module is receiving abnormal signals. Basic issues, such as coolant leaking into the transmission causing fluid emulsification, have also been encountered. During operation, pay attention to any metallic friction sounds or burnt smells, as these can aid in preliminary diagnosis. Remember to first check the dashboard warning lights and try restarting the engine to reset the system. If the problem persists, towing is necessary; pushing the vehicle on your own can easily cause secondary damage.
