Method and device for diagnosing a coolant pump for an internal combustion engine

A device for diagnosing a coolant pump which is provided for the purpose of circulating a coolant in a closed cooling circuit of an internal combustion engine and which can be activated and deactivated independently of the operating state of the internal combustion engine, comprising

• a facility for determining a value representing the coolant temperature,
• a facility for determining a value representing the cylinder head temperature,
• comparator facility for comparing the values representing the coolant temperature and the cylinder head temperature,
• a frequency counter that counts a number of comparison results lying outside a tolerance range defined by one or more predefined limits,
• assessment facility which rates the coolant pump as faulty when the number of comparison results lying outside the tolerance range exceeds a predefined maximum number, and
• fault management facility that have at least one of a fault memory and a fault indicator device for at least one of:
• storing a fault code and outputting a warning message in the event of a faulty coolant pump.

A device for diagnosing a coolant pump which is provided for the purpose of circulating a coolant in a closed cooling circuit of an internal combustion engine and which can be activated and deactivated independently of the operating state of the internal combustion engine, comprising an engine control unit comprising:

• a first temperature sensor for measuring the coolant temperature,
• a second temperature sensor for measuring the cylinder head temperature,
• a comparator comparing output values of said first and second temperature sensors,
• a frequency counter that counts a number of comparison results lying outside a tolerance range defined by one or more predefined limits,
• an assessment unit configured to rate the coolant pump as faulty when the number of comparison results lying outside the tolerance range exceeds a predefined maximum number, and
• a fault management unit comprising at least one of a fault memory and a fault indicator device for at least one of:
• storing a fault code and outputting a warning message in the event of a faulty coolant pump.