Abstract: The invention relates to a method for monitoring an ammonia slip catalytic converter which is arranged in an exhaust gas after-treatment device of an internal combustion engine, downstream of a catalytic converter arrangement, wherein the method comprises the steps of measuring a nitrogen oxide content in the exhaust gas by means of a sensor upstream of the ammonia slip catalytic converter, detecting a sensor signal of an ammonia-cross-sensitive nitrogen oxide sensor which is arranged downstream of the ammonia slip catalytic converter, and checking whether the ammonia-cross-sensitive nitrogen oxide sensor measures a higher value than the sensor.

Abstract: The invention relates to a method for monitoring an ammonia slip catalytic converter which is arranged in an exhaust gas after-treatment device of an internal combustion engine, downstream of a catalytic converter arrangement, wherein the method comprises the steps of measuring a nitrogen oxide content in the exhaust gas by means of a sensor upstream of the ammonia slip catalytic converter, detecting a sensor signal of an ammonia-cross-sensitive nitrogen oxide sensor which is arranged downstream of the ammonia slip catalytic converter, and checking whether the ammonia-cross-sensitive nitrogen oxide sensor measures a higher value than the sensor.