How to Resolve Abnormal Vehicle Speed Signal?
2 Answers
There are two possibilities: either the vehicle speed sensor is damaged, or the speed signal processing module in the instrument cluster is faulty. If the issue is not with the instrument cluster, it is necessary to visit a 4S shop for a computer diagnostic test. Replacing the sensor should resolve the problem.
Last time my car had an abnormal speed signal, my first thought was that this issue couldn't be delayed. Signal failure has a huge impact—the speedometer starts acting erratic, and ABS or cruise control also fails. As an owner who frequently tinkers with older cars, I first checked the sensors—it's usually a loose or dirty wheel speed sensor, simple enough to fix by just removing the wheel cover and cleaning the connector. If that doesn't work, test whether the circuit voltage is stable, and use an OBD scanner to read the fault codes, which might indicate a short circuit or severe wear. It gets worse in rainy weather or on bumpy roads, easily triggering safety warnings. I suggest not forcing it to drive and finding a proper repair shop for diagnosis and part replacement as soon as possible—after all, it affects braking responsiveness. Saving a little money isn't worth risking your life. During regular car washes, take extra care to wipe the undercarriage to reduce mud buildup. This process doesn't take much effort but can prevent major failures.
