What are the symptoms of a damaged tachometer in the Teana?
2 Answers
Symptoms include the inability to display the RPM correctly. The advantages of the car tachometer's operation are as follows: 1. Large static torque, the pointer is not easy to shake, and it has strong anti-vibration performance. 2. It uses a single-chip microprocessor through software design, so it has high precision and strong anti-interference ability. 3. The hour meter adopts LCD display, without mechanical parts, so it is more reliable and has a more modern feel. The working principle of the car tachometer is that the tachometer receives the digital pulse signal sent by the sensor, processes it, and directly reads it into the counting port of the CPU. The software calculates the RPM and the corresponding position of the pointer, and then through the control port of the CPU, it amplifies and drives the stepper motor to rotate in positive and negative directions. The pointer indicating the corresponding RPM value is directly installed on the rotating shaft of the stepper motor, and the stepper motor moves only 13 degrees per step.
My Teana has been running for almost a decade, and the symptoms were quite obvious after the tachometer broke. Initially, the needle didn't move at all, stuck at zero no matter how fast the engine revved. Later, the needle started fluctuating erratically—showing excessively high RPMs when accelerating on flat roads but getting stuck at low RPMs when decelerating, making it impossible to gauge the actual engine condition. I had to rely on listening to the engine sound to determine shift points while driving, especially when climbing hills in mountainous areas, which often led to mis-shifts and increased wear. Additionally, this issue sometimes affected the accuracy of the coolant temperature gauge or oil pressure gauge. Last week, I noticed the entire instrument panel dimming, and a check at the repair shop revealed that the RPM sensor had burned out or the wiring had aged and cracked. Delaying repairs would have prolonged engine strain and increased failure risks, so I immediately replaced the faulty part.
