Systems and methods for detecting degradation of catalyst members of an aftertreatment system

A method comprising:

• causing, by at least one controller, a first doser to cease dosing a first reductant portion of a reductant to a first exhaust portion of exhaust upstream of a first catalyst member disposed in a first leg of a selective catalytic reduction (SCR) system;
• causing, by the at least one controller, a second doser to dose a second reductant portion of the reductant to a second exhaust portion of the exhaust upstream of a second catalyst member disposed in a second leg of the SCR system;
• determining, by the at least one controller, a first conversion efficiency of the first leg while the first doser is not dosing the first reductant portion and the second doser is dosing the second reductant portion;
• causing, by the at least one controller, the second doser to cease dosing the second reductant portion to the second exhaust portion;
• causing, by the at least one controller, the first doser to dose the first reductant portion to the first exhaust portion;
• determining, by the at least one controller, a second conversion efficiency of the second leg while the first doser is dosing the first reductant portion and the second doser is not dosing the second reductant portion;
• comparing, by the at least one controller, the first conversion efficiency to a first conversion efficiency threshold;
• comparing, by the at least one controller, the second conversion efficiency to a second conversion efficiency threshold;
• and
• providing, by the at least one controller, an indication responsive to a determination that at least one of the first conversion efficiency is less than the first conversion efficiency threshold or the second conversion efficiency is less than the second conversion efficiency threshold.