How to Determine if the ABS Sensor is Good or Bad?
3 Answers
Methods to determine if the ABS sensor is good or bad: 1. Use a fault diagnostic tool to read the fault codes. If there is an issue with the sensor, a fault code will appear in the ABS computer, and the fault light on the dashboard will also illuminate; 2. Use a multimeter to measure the resistance of the ABS sensor. The resistance value should be between 1000 and 1300 ohms. If it falls outside this range, it indicates a problem with the ABS sensor. The ABS sensor is used in the ABS system of motor vehicles, and its function is to monitor the vehicle speed. The ABS sensor interacts with the toothed ring that rotates synchronously with the wheel to output a set of quasi-sinusoidal alternating current signals, the frequency and amplitude of which are related to the wheel speed. This output signal is transmitted to the ABS electronic control unit (ECU) to achieve real-time monitoring of the wheel speed.
Last time my car's ABS light came on, the mechanic taught me to check the trouble codes first. If the ABS system reports a fault, using a diagnostic tool to identify which specific sensor is faulty is the most accurate method. You can also pay attention to some abnormalities in daily use: if the brake pedal vibrates excessively or doesn't rebound at all when braking, or if the warning light suddenly comes on after driving through muddy or sandy roads, it could be due to the sensors being covered in mud. The simplest way is to jack up the car and spin the wheels while listening; a good sensor will make a slight clicking sound.
Our repair shop follows a three-step process to determine the condition of ABS sensors. First, we use a diagnostic tool to check the wheel speed data stream - inconsistent speed readings among the four wheels indicate a problem. Then we remove the sensor and measure its resistance, which should normally be between 800 and 1400 ohms; values outside this range mean it's faulty. Finally, we test by moving a magnet close to and away from the sensor - the detection head should trigger voltage fluctuations when attracted by the magnet. However, damaged wiring harnesses for wheel speed sensors can also cause false alarms, so we need to peel back the rubber sleeve to check for corrosion or broken wires.
