The DPF filters particulate matter (PM). When the amount of PM reaches to a certain limit, the ECM changes the fuel burning to a mode that cleans the DPF (burns PM) while the vehicle is in a certain drive mode.

EGT sensor 1/2 detects the temperature of the exhaust system.

EGT sensor 1 is attached to the upper side of the warm up catalytic converter, and it detects exhaust gas temperature before the warm up catalytic converter.

EGT sensor 2 is attached to the front side of the DPF, and it detects exhaust gas temperature between the warm up catalytic converter and the DPF.

The DPF differential pressure sensor detects the pressure difference of the exhaust gas at the upstream side and the downstream side of the DPF. This is used to detect how much PM is accumulated on the DPF.