Method for pinpointing a short-circuit

1. A method for pinpointing a short-circuit in a wide-range air/fuel sensor having one or more sensor-terminals, the one or more sensor-terminals being one or more of a reference-terminal, a pump-terminal, a return-terminal, and a tag-terminal, said method comprising:

controlling a connection of a source of electric current to the one or more sensor-terminals;

determining one or more status-values based on signals present at the sensor-terminals;

determining a sensor-status of the wide-range air/fuel sensor based on the connection of source of electric current and the one or more status-values;

determining a first-value based on a difference between signals at the reference-terminal and the return-terminal while the source of electric current is disconnected;

determining a second-value based on the difference between signals at the reference-terminal and the return-terminal while the source of electric current is connected to the reference-terminal;

determining a reference-error based on the difference between the second-value and the first-value; and

determining that a short-circuit is present on the reference-terminal when a reference-threshold is greater than the reference-error.

2. The method in accordance with claim 1 further comprising controlling the connection of three test-resistors that are each selectively connectable between two of the sensor-terminals.

3. The method in accordance with claim 2 , wherein the three test-resistors include a first-test-resistor, a second-test-resistor, and a third-test-resistor, the method further comprising:

controlling the connection of a first-test-resistor between the reference-terminal and the return-terminal;

controlling the connection of a second-test-resistor between the return-terminal and the pump-terminal; and

controlling the connection of a third-test-resistor is selectively connected between the pump-terminal and the tag-terminal.

4. A method for pinpointing a short-circuit in a wide-range air/fuel sensor having one or more sensor-terminals, the one or more sensor-terminals being one or more of a reference-terminal, a pump-terminal, a return-terminal, and a tag-terminal, said method comprising:

controlling a connection of a source of electric current to the one or more sensor-terminals;

determining one or more status-values based on signals present at the sensor-terminals;

determining a sensor-status of the wide-range air/fuel sensor based on the connection of source of electric current and the one or more status-values;

determining a third-value based on a difference between signals at the pump-terminal and the return-terminal while the source of electric current is disconnected

determining a fourth-value based on the difference between signals at the pump-terminal and the return-terminal while the source of electric current is connected to the pump-terminal;

determining a pump-error based on the difference between the fourth-value and the third-value; and

determining that a short-circuit is present on the pump-terminal when a pump-threshold is greater than the pump-error.

5. The method in accordance with claim 4 further comprising controlling the connection of three test-resistors that are each selectively connectable between two of the sensor-terminals.

6. The method in accordance with claim 5 , wherein:

the three test-resistors include a first-test-resistor, a second-test-resistor, and a third-test-resistor;

the first-test-resistor is not connected between the reference-terminal and the return-terminal;

the second-test-resistor is connected between the return-terminal and the pump-terminal; and

the third-test-resistor is connected between the pump-terminal and the tag-terminal.

7. A method for pinpointing a short-circuit in a wide-range air/fuel sensor having one or more sensor-terminals, the one or more sensor-terminals being one or more of a reference-terminal, a pump-terminal, a return-terminal, and a tag-terminal, said method comprising:

controlling a connection of a source of electric current to the one or more sensor-terminals;

determining one or more status-values based on signals present at the sensor-terminals;

determining a sensor-status of the wide-range air/fuel sensor based on the connection of source of electric current and the one or more status-values;

determining a fifth-value based on a difference between signals at the tag-terminal and the pump-terminal while the source of electric current is disconnected;

determining a sixth-value based on the difference between signals at the tag-terminal and the pump-terminal while the source of electric current is connected to the tag-terminal;

determining a tag-error based on the difference between the sixth-value and the fifth-value; and

determining that a short-circuit is present on the tag-terminal when a tag-threshold is greater than the tag-error.

8. The method in accordance with claim 7 further comprising controlling the connection of three test-resistors that are each selectively connectable between two of the sensor-terminals.

9. The method in accordance with claim 8 , wherein:

the three test-resistors include a first-test-resistor, a second-test-resistor, and a third-test-resistor;

the first-test-resistor is not connected between the reference-terminal and the return-terminal;

the second-test-resistor is connected between the return-terminal and the pump-terminal; and

the third-test-resistor is connected between the pump-terminal and the tag-terminal.

10. A method for pinpointing a short-circuit in a wide-range air/fuel sensor having one or more sensor-terminals, the one or more sensor-terminals being one or more of a reference-terminal, a pump-terminal, a return-terminal, and a tag-terminal, said method comprising:

controlling a connection of a source of electric current to the one or more sensor-terminals;

determining one or more status-values based on signals present at the sensor-terminals;

determining a sensor-status of the wide-range air/fuel sensor based on the connection of source of electric current and the one or more status-values;

determining a first-value based on a difference between signals at the reference-terminal and the return-terminal while the source of electric current is disconnected;

determining a second-value based on the difference between signals at the reference-terminal and the return-terminal while the source of electric current is connected to the reference-terminal;

determining a reference-error based on the difference between the second-value and the first-value;

determining that a short-circuit is present on the reference-terminal when a reference-threshold is greater than the reference-error;

determining a third-value based on the difference between signals at the pump-terminal and the return-terminal while the source of electric current is disconnected;

determining a fourth-value based on the difference between signals at the pump-terminal and the return-terminal while the source of electric current is connected to the pump-terminal;

determining a pump-error based on the difference between the fourth-value and the third-value;

determining that the short-circuit is present on the pump-terminal when a pump-threshold is greater than the pump-error;

determining a fifth-value based on the difference between signals at the tag-terminal and the pump-terminal while the source of electric current is disconnected;

determining a sixth-value based on the difference between signals at the tag-terminal and the pump-terminal while the source of electric current is connected to the tag-terminal;

determining a tag-error based on the difference between the sixth-value and the fifth-value;

determining that the short-circuit is present on the tag-terminal when a tag-threshold is greater than the tag-error; and

determining that the short-circuit is present on the return-terminal when the reference-error is greater than the reference-threshold and when the pump-error is greater than the pump-threshold and when the tag-error is greater than the tag-threshold.

11. The method in accordance with claim 10 further comprising controlling the connection of three test-resistors that are each selectively connectable between two of the sensor-terminals.

12. The method in accordance with claim 11 , wherein:

the three test-resistors include a first-test-resistor, a second-test-resistor, and a third-test-resistor;

the first-test-resistor is connected between the reference-terminal and the return-terminal, the second-test-resistor is connected between the return-terminal and the pump-terminal, and the third-test-resistor is connected between the pump-terminal and the tag-terminal when the first-value and the second-value are determined; and

the first-test-resistor is not connected between the reference-terminal and the return-terminal, the second-test-resistor is connected between the return-terminal and the pump-terminal, and the third-test-resistor is connected between the pump-terminal and the tag-terminal when the third-value, the fourth-value, the fifth-value and the sixth-value are determined.