An evaluation and control unit, designed as an ASIC, for operating a broadband lambda sensor that includes at least one electrical line. The evaluation and control unit includes at least one electrical terminal for electrically connecting to the electrical line of the broadband lambda sensor, and a device for determining a setpoint value of a current flowing into the electrical terminal and for comparing this setpoint value with the current actually flowing into the electrical terminal and for comparing with the aid of comparators the electrical potential being applied to the electrical terminal with predefined limits.

Disclosed is a method for detecting a malfunction of a voltage-limiting circuit of a control circuit, the control circuit including an output port connected to a capacitive actuator of a motor vehicle, an output voltage on the output port being, in the absence of a malfunction of the voltage-limiting circuit, equal to or lower than a theoretical maximum value. The capacitive actuator is arranged in series with a commutator, the method including steps of: placing the commutator in an open state; activating the control circuit; measuring the output voltage over the output port; and evaluating a criterion for detecting a malfunction of the voltage-limiting circuit as a function of the output voltage.

A method and a device for performing diagnostics on an exhaust gas sensor includes a series circuit of a Nernst cell and a first other cell. The exhaust gas sensor has a first, a second, and a third connection where a voltage drop can be measured between the first connection and the second connection by the Nernst cell and a voltage drop between the second connection and the third connection can be measured by the first other cell. The diagnostic method has steps for feeding a direct or alternating current into the first, second, and third connections; for directly or indirectly sensing an electrical voltage potential at at least one of the first, second, and third connections; and for evaluating the voltage potential sensed to diagnose a short circuit or an open circuit in the Nernst cell and/or in the first other cell.

A method includes determining a first voltage that is in a high-side path of a circuit, the path including a high-side switch connected between a first potential connection of the circuit and a first connection of a load of the circuit; determining a second voltage that is in a low-side path of the circuit, the path including a low-side switch connected between a second potential connection of the circuit and a second connection of the load; responsive to a determination that one of the voltages exceeds a threshold for at least a duration of a predefined time interval, checking whether the other voltage currently exceeds the threshold; and determining that there is a short circuit across the load or in whichever of the paths has the voltage that exceeded the threshold for the duration, respectively, if the result of the check is positive or negative.

An EHC line leakage diagnosis method can operate a heater of an oxygen detector when satisfying one or more conditions of an engine off time, a coolant temperature, and an outside air temperature by a diagnosis controller upon the key-on of the non-operation of an engine, and then, determine the normality or abnormality of a temperature drop using a change in a temperature value of a signal value and the temperature value detected by the oxygen detector after an air pump is driven, and then confirm the leakage of an exhaust line and a line on the rear end portion of an EHC valve of an air line using the number of times of the occurrence of the abnormality of the temperature drop, and can perform the failure diagnosis without generating the exhaust gas by not operating an engine.

Disclosed is a method for diagnosing a speed/position sensor of an internal combustion engine, of the type including a toothed wheel, which rotates as one with a shaft, and a matter detector, which is arranged so as to be fixed opposite the toothed wheel and controls a base of a transistor. The method includes: detecting a short circuit between an output of the speed/position sensor and a power supply; and testing for excess current consumption by a power supply of the speed/position sensor when the transistor is activated. If the test is positive, the short circuit is identified between the power supply of the speed/position sensor and the output of the speed/position sensor. Alternatively, if the test is negative, the short circuit is identified between another power supply and the output of the speed/position sensor.

A method includes determining a first voltage that is in a high-side path of a circuit, the path including a high-side switch connected between a first potential connection of the circuit and a first connection of a load of the circuit; determining a second voltage that is in a low-side path of the circuit, the path including a low-side switch connected between a second potential connection of the circuit and a second connection of the load; responsive to a determination that one of the voltages exceeds a threshold for at least a duration of a predefined time interval, checking whether the other voltage currently exceeds the threshold; and determining that there is a short circuit across the load or in whichever of the paths has the voltage that exceeded the threshold for the duration, respectively, if the result of the check is positive or negative.

An electromagnetic valve driving device which drives a fuel injection valve having a solenoid coil, includes: a regenerative switching element disposed between a first end portion of the solenoid coil and the ground; and a control unit configured to control the regenerative switching element to be in an ON state or an OFF state, wherein the control unit includes: a voltage detection unit configured to detect a voltage of the first end portion of the solenoid coil; and an abnormality detection unit configured to detect an abnormality of the regenerative switching element on the basis of the voltage detected by the voltage detection unit.

An electromagnetic valve driving device which drives a fuel injection valve having a solenoid coil, includes: a regenerative switching element disposed between a first end portion of the solenoid coil and the ground; and a control unit configured to control the regenerative switching element to be in an ON state or an OFF state, wherein the control unit includes: a voltage detection unit configured to detect a voltage of the first end portion of the solenoid coil; and an abnormality detection unit configured to detect an abnormality of the regenerative switching element on the basis of the voltage detected by the voltage detection unit.

Disclosed is a method for detecting a malfunction of a voltage-limiting circuit of a control circuit, the control circuit including an output port connected to a capacitive actuator of a motor vehicle, an output voltage on the output port being, in the absence of a malfunction of the voltage-limiting circuit, equal to or lower than a theoretical maximum value. The capacitive actuator is arranged in series with a commutator, the method including steps of: placing the commutator in an open state; activating the control circuit; measuring the output voltage over the output port; and evaluating a criterion for detecting a malfunction of the voltage-limiting circuit as a function of the output voltage.