What causes the speedometer to sometimes work and sometimes not?
2 Answers
Here are the specific methods for diagnosing a speedometer that intermittently works and stops: 1. Check if the vehicle speed sensor is damaged, inspect whether the sensor connector has a loose connection, examine if there are faults in the sensor's drive mechanism, and verify if there are any fault codes in the vehicle's wheel speed sensor and ABS control unit system. 2. The fault may be caused by the speedometer itself inside the instrument cluster or a loose connection of the instrument cluster connector. The instrument cluster can be diagnosed using a fault diagnostic tool to retrieve fault codes or perform an action test to determine if the issue lies with the speedometer itself. 3. The speedometer indicates the vehicle's speed via a needle pointer, displaying instantaneous speed rather than the total mileage. The speedometer's indication relies on the vehicle speed sensor, which is typically installed on the transmission.
I've been driving for many years and have encountered similar issues. The speedometer working intermittently is usually due to a problem with the vehicle speed sensor. The sensor is located near the wheels or transmission and is responsible for sending speed signals. If the sensor is dirty, worn out, or loose, the signal can become inconsistent, causing the dashboard display to flicker. Another common cause is unstable wiring connections, where vibrations from bumpy roads lead to poor contact at the connectors. It could also be a blown fuse interrupting the circuit. I once experienced this myself—while driving, the dashboard flickered, and upon inspection, I found the sensor plug had come loose. This is dangerous because inaccurate speed readings can lead to speeding or accidents. I recommend first checking basic components like the sensor and fuses. If that doesn't resolve the issue, take it to a professional auto repair shop for diagnosis with specialized tools. Don't delay, as it poses a safety risk.