OBD-II regulations require that the EGR system be tested. Technician A says that the PCM can monitor the commanded position of the EGR valve to determine if it is functioning correctly. Technician B says that the PCM can open the EGR valve and monitor for a change in the MAP sensor or oxygen sensor reading to detect if the system is functioning correctly. Which technician is correct?

Question

Quizplus · Accepted Answer

Both technicians A and B are correct. The PCM (Powertrain Control Module) can indeed monitor the commanded position of the EGR (Exhaust Gas Recirculation) valve to check its functionality, as stated by Technician A. Additionally, as Technician B mentions, the PCM can also open the EGR valve and monitor changes in the MAP (Manifold Absolute Pressure) sensor or oxygen sensor readings to determine if the EGR system is working correctly. Both methods are valid diagnostic approaches for the EGR system under OBD-II regulations.

OBD-II Regulations Require That the EGR System Be Tested