Method for operating an engine control module under low voltage conditions

A fault clearing system for an engine control system, comprising:

• a plurality of processor modules operable to control and monitor an engine including an electronic throttle control (ETC) module operable to control and monitor a throttle of said engine, said processor modules setting faults based on outputs from a plurality of engine sensors and ETC sensors;
• and
• an ETC diagnostic module that monitors said ETC sensors and said engine sensors, said ETC diagnostic module setting a low voltage induced fault, and entering one of a plurality of low voltage states in response to said low voltage induced fault, wherein said ETC diagnostic module controls said ETC module to selectively clear said faults in said ETC module and said plurality of processor modules upon entry into said one of said low voltage states,
• wherein said plurality of low voltage states of said ETC diagnostic module includes a low voltage recovery state selected by said ETC diagnostic module when measured voltages received from said engine sensors and said ETC sensors are greater than a first calibration voltage for greater than a first calibration time, and
• wherein said low voltage recovery state generates ETC diagnostic signals clearing low voltage faults for said ETC module and said plurality of processor modules and disables fuel to said engine, until a first timer is greater than said first calibration time, thereafter, said low voltage recovery state ends and said ETC diagnostic module returns to normal operation where none of said plurality of low voltage states are selected.

A method of clearing low voltage faults of an engine control system, comprising:

• monitoring vehicle voltages and faults;
• setting one of a plurality of low voltage states in response to a low voltage induced fault, wherein said low voltage states selectively control an electronic throttle control (ETC);
• and
• selectively clearing said faults in said engine control system upon entry into said one of said low voltage states,
• wherein said plurality of low voltage states includes (i) a low power state selected when said ETC is already in a limited-power mode, wherein said low power state disables said low voltage fault clearing method and said ETC and said engine remain in said limited-power mode, and (ii) a crank transition state, wherein said crank transition state is selected when:
• said monitored voltages are above a first calibration voltage for more than a first calibration time as long as a low voltage non-cranking state does not already exist;
• said monitored voltages are below a second calibration voltage;
• monitored engine RPM is below a calibration RPM;
• and an engine starter is currently cranking and has been cranking for less than a second calibration time.

A method of clearing low voltage faults of an engine control system, comprising:

• monitoring vehicle voltages and faults;
• setting one of a plurality of low voltage states in response to a low voltage induced fault, wherein said low voltage states selectively control an electronic throttle control (ETC), and wherein said plurality of low voltage states includes a low voltage recovery state that is selected when said monitored voltages are greater than a first calibration voltage for greater than a first calibration time;
• and
• selectively clearing said faults in said engine control system upon entry into said one of said low voltage states,
• wherein said low voltage recovery state clears low voltage induced faults for said ETC and said engine, and disables fuel to said engine, until said monitored voltages are greater than said first calibration voltage for more than said first calibration time, thereafter, said low voltage recovery state ends and said low voltage fault clearing method returns to normal operation where none of said plurality of low voltage states are selected.