Electronic control unit

1. An electronic control unit that is mounted on a vehicle which is configured to be charged with an external power supply and that receives a pilot signal via a charging cable before being supplied with a power when the vehicle is connected to the external power supply via the charging cable, the electronic control unit comprising:

a control line that is connected to a pilot signal line connecting a charging cable connector disposed in the vehicle to the electronic control unit;

a processor that performs a process necessary for a control of charging based on the pilot signal input via the control line;

a pilot voltage setting circuit that is connected between the control line and a ground and that includes a serial circuit of a pull-down resistor and a switching element controlled by the processor;

a voltage supply circuit that includes at least one of a first diagnosis voltage supply circuit supplying a first diagnosis voltage to the control line under control of the processor and a second diagnosis voltage supply circuit supplying a second diagnosis voltage to the pilot signal line via an abnormality diagnosis line connected to the pilot signal line at the charging cable connector under control of the processor; and

an abnormality diagnosis circuit that is connected to the pull-down resistor and the switching element and that outputs an abnormality diagnosis result signal of at least one of the switching element and the pilot signal line to the processor,

wherein the processor performs at least one of a first diagnosis process of determining whether or not the switching element is abnormal based on an output signal of the abnormality diagnosis circuit obtained when turning on and off the switching element while controlling the first diagnosis voltage supply circuit to supply the first diagnosis voltage to the control line and a second diagnosis process of determining whether or not the pilot signal line is abnormal based on the output signal of the abnormality diagnosis circuit obtained when controlling the second diagnosis voltage supply circuit to supply the second diagnosis voltage to the pilot signal line in a state where the switching element is maintained in OFF state.

2. The electronic control unit according to claim 1 , wherein the voltage supply circuit includes only the first diagnosis voltage supply circuit, and

wherein the processor determines whether or not the switching element is abnormal based on a level of the output signal of the abnormality diagnosis circuit obtained when turning on and off the switching element while controlling the first diagnosis voltage supply circuit to supply the first diagnosis voltage of a fixed voltage to the control line as the first diagnosis process.

3. The electronic control unit according to claim 1 , wherein the voltage supply circuit includes only the first diagnosis voltage supply circuit, and

wherein the processor determines whether or not the switching element is abnormal based on an edge of the output signal of the abnormality diagnosis circuit obtained when turning on and off the switching element while controlling the first diagnosis voltage supply circuit to supply the first diagnosis voltage, which is a pulse-like voltage, with a predetermined frequency to the control line as the first diagnosis process.

4. The electronic control unit according to claim 1 , wherein the voltage supply circuit includes only the second diagnosis voltage supply circuit, and

wherein the processor determines whether or not the pilot signal line is abnormal based on a level of the output signal of the abnormality diagnosis circuit obtained when controlling the second diagnosis voltage supply circuit to supply the second diagnosis voltage of a fixed voltage to the pilot signal line in a state where the switching element is maintained in OFF state as the second diagnosis process.

5. The electronic control unit according to claim 1 , wherein the voltage supply circuit includes only the second diagnosis voltage supply circuit, and

wherein the processor determines whether or not the pilot signal line is abnormal based on an edge of the output signal of the abnormality diagnosis circuit obtained when controlling the second diagnosis voltage supply circuit to supply the second diagnosis voltage, which is a pulse-like voltage, with a predetermined frequency to the pilot signal line in a state where the switching element is maintained in OFF state as the second diagnosis process.

6. The electronic control unit according to claim 4 , wherein the processor performs the second diagnosis process when the charging cable is not connected to the vehicle.

7. The electronic control unit according to claim 1 , wherein the voltage supply circuit includes both the first diagnosis voltage supply circuit and the second diagnosis voltage supply circuit, and

wherein the processor performs the second diagnosis process after performing the first diagnosis process.

8. The electronic control unit according to claim 7 , wherein the processor first determines whether or not the switching element is abnormal based on a level of the output signal of the abnormality diagnosis circuit obtained when turning on and off the switching element while controlling the first diagnosis voltage supply circuit to supply the first diagnosis voltage of a fixed voltage to the control line as the first diagnosis process, and

then determines whether or not the pilot signal line is abnormal based on a level of the output signal of the abnormality diagnosis circuit obtained when controlling the second diagnosis voltage supply circuit to supply the second diagnosis voltage of a fixed voltage to the pilot signal line in a state where the switching element is maintained in OFF state as the second diagnosis process.

9. The electronic control unit according to claim 7 , wherein the processor first determines whether or not the switching element is abnormal based on an edge of the output signal of the abnormality diagnosis circuit obtained when turning on and off the switching element while controlling the first diagnosis voltage supply circuit to supply the first diagnosis voltage, which is a pulse-like voltage, with a predetermined frequency to the control line as the first diagnosis process, and

then determines whether or not the pilot signal line is abnormal based on an edge of the output signal of the abnormality diagnosis circuit obtained when controlling the second diagnosis voltage supply circuit to supply the second diagnosis voltage, which is a pulse-like voltage, with a predetermined frequency to the pilot signal line in a state where the switching element is maintained in OFF state as the second diagnosis process.

10. The electronic control unit according to claim 7 , wherein the processor performs the second diagnosis process after performing the first diagnosis process when the charging cable is not connected to the vehicle.

11. The electronic control unit according to claim 5 , wherein the processor performs the second diagnosis process when the charging cable is not connected to the vehicle.

12. The electronic control unit according to claim 8 , wherein the processor performs the second diagnosis process after performing the first diagnosis process when the charging cable is not connected to the vehicle.

13. The electronic control unit according to claim 9 , wherein the processor performs the second diagnosis process after performing the first diagnosis process when the charging cable is not connected to the vehicle.