What does it mean when the DEF light comes on in a car?
1 Answers
The DEF light in a car indicates that the auxiliary water tank is low on water. If the DEF light appears on the small mileage display of the instrument panel, it signifies a fault in the instrument's internal processor. Below are detailed explanations regarding the DEF light being on: 1. Methods to check for internal instrument faults after the light comes on: The tap-and-press method can be used to diagnose the issue, as most faults are caused by poor contact or soldering problems. Alternatively, the comparison method can be employed, which requires two identical instruments, one of which is functioning normally. Compare the voltage, waveform, static impedance, output results, current, etc., of the instruments. If these are all normal, the issue might be with the instrument's signal. If the signals differ, the fault is likely here, and professional repair is needed. 2. Introduction to the car instrument panel: It is a device that reflects the working conditions of various vehicle systems. Common indicators include the fuel indicator, washer fluid indicator, electronic throttle indicator, front and rear fog light indicators, and warning lights. Instrument panels vary between cars, but conventional instruments generally include the speedometer, tachometer, oil pressure gauge, water temperature gauge, fuel gauge, and charge gauge. Beneath the surface of modern car instrument panels, various indicator or warning lights are installed, such as the coolant level warning light, fuel level indicator, washer fluid level indicator, charge indicator, high/low beam indicator, transmission gear indicator, Anti-lock Braking System (ABS) indicator, traction control indicator, and Supplemental Restraint System (SRS) warning light.
