Who is correct regarding how RPM is read on vehicles equipped with an OBD II system?

When considering how RPM is read on vehicles equipped with an OBD II system, it’s essential to understand the role of the OBD II system in monitoring engine functions. The OBD II system accesses vital data from various sensors, including the engine speed sensor, to provide real-time information about the vehicle’s operating conditions, which includes RPM.

Both technicians might highlight important aspects regarding how RPM is derived and interpreted. It could be that one technician discusses the direct reading from the engine control module (ECM), while the other may refer to checking measurements through a diagnostic tool. Both methods are valid within the context of the OBD II framework. The OBD II system's capability to reflect accurate information about the engine's performance makes it possible for multiple techniques to successfully analyze RPM readings.

Understanding this, both technicians can be correct as their statements likely reflect different, yet complementary, approaches to reading RPM through OBD II technology. Each technician's perspective contributes to a comprehensive understanding of how RPM is monitored on these vehicles, confirming that both are indeed correct.