Method, device and computer program product for diagnosing of at least one exhaust emission control unit

摘要

A method, device and computer program product are provided for diagnosing of a NOx-reducing catalyzer that can be regenerated and/or of a three-way valve for directing the flow of exhaust gases into a bypass pipe, and/or of a clean-up catalyzer. All the components can be included in one and the same exhaust emission control system. The diagnosing of the NOx-reducing catalyzer and of the three-way valve is carried out by method steps comprising measurement of the drop in pressure across the NOx-reducing catalyzer. The diagnosing of the clean-up catalyzer is carried out by method steps comprising measurement of the increase in temperature in the clean-up catalyzer. In the event of reduced functionality of the NOx catalyzer, a deSOx is carried out. A fault code is generated in the event of reduced functionality of the three-way valve or of the clean-up catalyzer.