1. Wheel speed sensor failure: If one or more of the wheel speed sensors fails, it can cause the ABS light to come on, the transmission to shift harshly, and the speedometer to stop working. Inspect the wheel speed sensors for damage or corrosion and replace them if necessary.
2. Transmission solenoid failure: A faulty transmission solenoid can cause the transmission to shift harshly. Diagnose the transmission and replace the faulty solenoid if needed.
3. Faulty instrument cluster: A malfunctioning instrument cluster can cause the speedometer to stop working and can affect other instrument cluster gauges. Verify that the instrument cluster is receiving power and ground, and inspect the instrument cluster for damage. Repair or replace the instrument cluster if necessary.
4. Wiring issues: Loose or damaged wiring can cause malfunctions in the ABS system, transmission, and instrument cluster. Inspect the wiring for damage and corrosion, and repair or replace any faulty wiring as needed.
It is advisable to have these issues diagnosed and repaired by a qualified mechanic because they may indicate underlying problems with the ABS system, transmission, or other vehicle components.
