ASE Engine Performance (A8) Practice Test

Checking sensor resistance in a vehicle speed sensor is crucial for verifying sensor functionality. The resistance measurement helps identify whether the sensor is operating within its specified range. A properly functioning vehicle speed sensor is essential for accurately measuring the speed of the vehicle, which is used by the Engine Control Module (ECM) for various functions, including calculating the vehicle's speed for transmission shifting and engine management strategies. If the resistance is outside the expected range, it may indicate a faulty sensor, which could lead to incorrect readings and affect vehicle performance.

Understanding this aspect is vital for troubleshooting and ensuring that the vehicle's systems are working correctly. Other options do not directly relate to the purpose of checking sensor resistance; for example, while transmission efficiency and tachometer accuracy may be influenced by the speed sensor, those assessments involve different diagnostic approaches. Checking the sensor's resistance specifically provides insight into the condition and operational status of the sensor itself.