Regarding sensor problems, who is correct: Technician A says a poor ground in the reference voltage circuit can cause higher readings, Technician B says small amounts of resistance will not significantly affect performance?

A poor ground in the reference voltage circuit can indeed lead to higher readings from various sensors. This occurs because sensors rely on a stable reference voltage to accurately measure and transmit data. When the ground connection is compromised or has excessive resistance, it can decrease the sensor's ability to deliver accurate readings, often resulting in erratic or elevated voltage signals.

For example, if a sensor is designed to read 5 volts but experiences a poor ground, it may read significantly higher due to the lack of a proper return path for the current. This misread can lead to incorrect data being sent to the vehicle's control modules, which can affect overall vehicle performance and diagnostics.

On the other hand, while it's true that small amounts of resistance can sometimes be negligible in certain contexts, in automotive electrical systems, especially with sensitive components like sensors, even minor resistance in a reference voltage circuit can have substantial effects on performance and accuracy. Therefore, assertions about negligible resistances might not hold in all situations, making Technician A's statement the more accurate one in this context.