Final answer:
Technician B is likely correct; the 37.3mV reading indicates a potential difference due to excessive resistance in the TPS ground, not the signal voltage. Such a voltage discrepancy can affect sensor operation and needs further investigation.
Step-by-step explanation:
The question pertains to the readings obtained from a digital voltmeter when connected to a throttle position sensor (TPS) and battery in an automotive scenario. Technician A interprets the 37.3mV reading as the signal voltage and suggests it might be low, while Technician B attributes the reading to excessive resistance in the throttle position sensor's ground connection.
Given that the voltmeter is connected between the sensor ground and battery negative (both of which should ideally be at the same electrical potential), a non-zero reading suggests there is potential difference due to some form of resistance or fault. The reading does not represent the actual signal voltage of the TPS, which would be measured between the sensor signal output and a proper ground or reference point when the throttle is actuated.
Therefore, Technician B is more likely correct in suggesting that the TPS ground has excessive resistance. The 37.3mV reading indicates a potential difference that could be caused by a poor ground connection. This can lead to erratic sensor behavior and incorrect signal voltages being sent to the engine control module (ECM).
It's important to note that battery testers, as mentioned in the reference material, measure terminal voltage under load. They provide information on the internal resistance and condition of a battery, which is different from testing the sensor ground connection in the provided question. When interpreting sensor voltages and diagnostics, a clear understanding of the electrical connections and expected readings is essential.