Fig.1) APS 1 signal and APS 2 signal are measured simultaneously, Check if output value is rising and APS 2 signal is 1/2 of APS 1 signal.

☞ APS 2 ground checking signal is for ECM to monitor APS 2. This signal drops APS 2 output voltage to below 200.39mV per 200msec. If APS 2 output voltage does not drop to below 200.39mV, ECM sets DTC as recognizing ground circuit error of APS 2