Camshaft or crankshaft sensor for automotive vehicle and diagnostic method for such a sensor

A method (50) of diagnosing a motor vehicle camshaft or crankshaft sensor (10), comprising:

• a step of providing a sensor for sensing a presence of a tooth of a toothed target that rotates with the camshaft or crankshaft, the sensor having each of
• a measuring cell (12) that supplies a raw analog signal corresponding to variations of a magnetic field induced by a rotation of the toothed target,
• an output port (17), and
• a processor module (14), connected to the output port and the measuring cell (12), that processes the raw signal, the processor module (14) configured to operate in either of two distinct operating modes, a first of the operating modes being a measurement mode and a second of the operating modes being a diagnostic mode,
• the processor module (14) further configured to switch between i) operating in the measurement mode in which the processor module (14) supplies at said output port (17) a measurement signal representing times of passage of teeth of the target (11) at a level of the measuring cell (12), and ii) operating in the diagnostic mode in which the processor module (14) supplies at said output port (17) a diagnostic signal, different from the measurement signal and representing amplitudes of the raw signal;
• a configuration step (51) of sending a predefined message to the processor module (14) to cause the processor module (14) to operate in the diagnostic mode;
• a recurrent recovery step (52) of recovering the diagnostic signal at the output port (17), the diagnostic signal corresponding to a value of a local maximum and/or a local minimum of the raw signal;
• and
• a diagnostic step (53) of diagnosing the sensor (10) by comparing the diagnostic signals recovered at the output port of the sensor.

A diagnostic module (40) for diagnosing a camshaft or crankshaft sensor (10), comprising:

• means for interfacing with an output port of the camshaft or crankshaft sensor (10);
• and
• processing means having a memory connected thereto, said processing means configured to perform functions of
• transmitting a message via the output port to a processor module (14) of the camshaft or crankshaft sensor (10) that causes said processor module (14) to switch from operating in a measurement mode in which the processor module (14) supplies at said output port a measurement signal representing times of passage of teeth of a target at a level of a measuring cell (12) to a diagnostic mode in which the processor module supplies at said output port a diagnostic signal, different from the measurement signal and representing an amplitude of a raw analog signal produced by the measuring cell,
• recurrently recovering the diagnostic signal from the output port and storing the diagnostic signal in the memory, so as to recurrently store a plurality of diagnostic signals corresponding to a value of a local maximum and/or a local minimum of a raw signal generated by the sensor, and
• comparing the diagnostic signals.

An electronic sensing apparatus for sensing a position of a toothed target (11) that rotates with an operative rotation of a machine, the apparatus comprising:

• a measuring cell (12) that detects variations in a magnetic field inducted thereupon by rotation of the toothed target (11);
• an output port;
• and
• a processor module (14), connected to the output port and the measuring cell (12), that processes a raw analog signal received from the measuring cell (12), the processor module (14) configured to operate in either of two distinct operating modes, a first of the operating modes being a measurement mode and a second of the operating modes being a diagnostic mode,
• the processor module (14) further configured to switch between operating in the measurement mode and the diagnostic mode in response to receiving a predefined message for configuring the processor module (14),
• wherein in the measurement mode, the processor module (14) processes the raw signal and supplies at said output port (17) a measurement signal representing times of passage of teeth of the target (11) at a level of the measuring cell (12), and
• wherein in the diagnostic mode, the processor module (14) supplies at said output port (17) a diagnostic signal, different from the measurement signal and representing amplitudes of the raw signal.