What are the symptoms of a faulty transmission oil temperature sensor?
3 Answers
Transmission oil temperature sensor failure symptoms include: 1. Jerky starts; 2. Gear shift shocks in 2nd and 3rd gears, delayed reverse gear engagement; 3. Abnormal noises and transmission fault warnings. The transmission oil temperature sensor is installed on the valve body inside the automatic transmission oil pan. Its function is to detect the temperature of the automatic transmission hydraulic fluid, serving as the basis for the electronic control unit to perform shift control, oil pressure control, and lock-up clutch control. Inside the transmission oil temperature sensor is a negative temperature coefficient semiconductor thermistor - the higher the temperature, the lower the resistance. Its resistance-temperature characteristic curve is similar to that of the negative temperature coefficient thermistor in coolant temperature sensors. The ECU determines the automatic transmission hydraulic fluid temperature by monitoring changes in its resistance.
Last week, I ran into trouble with a faulty transmission fluid temperature sensor while driving. At first, the warning light inexplicably came on, staring at me like a pair of red eyes. Then, when accelerating on the highway, the gear shifts felt extremely jerky, like a glitchy VCR. A few times, when I tried to overtake, the car just sluggishly refused to move, and the noise increased significantly—the whole vehicle felt incredibly sluggish. Later, the problem worsened in hot weather, especially when starting from a stop at traffic lights, which became even more laborious. I suspect it might have been due to overheating transmission fluid causing insufficient lubrication. If left unrepaired, the potential risks are quite serious, such as internal component wear or even complete failure, so I rushed to the repair shop to get it fixed. Don’t underestimate this kind of sensor failure—it affects driving safety, especially during long trips where it could lead to major issues.
When working on cars, I often encounter transmission fluid temperature sensor failures. The typical symptoms start with the warning light on the dashboard flashing, as if alerting you that something's wrong. Then comes abnormal transmission behavior, such as noticeably slower gear shifts during normal driving or sometimes outright delays, accompanied by sluggish acceleration that feels like an elderly person walking slowly. The issue becomes more pronounced after the car warms up, and prolonged driving under these conditions can also affect fuel efficiency, so extra caution is needed. My usual approach is to first check if the sensor connector is loose or if a fuse has blown. If that doesn't resolve it, I'll remove the sensor and seek professional help. For prevention, regular maintenance can help identify potential issues early, such as checking the fluid condition, which can save unnecessary trouble.
