GMC Sierra 3500 HD check engine light and exhaust fluid quality issue after NoX sensor replacement on GMC Sierra 3500 HD

Some GMC Sierra 3500 HD owners report experiencing issues with the check engine light and exhaust fluid quality after replacing the NOx sensor. These problems may manifest as slow acceleration, loss of power, irregular idling, engine hesitation, high fuel consumption, increased tailpipe emissions, foul odors from the exhaust, and even stalling. It's crucial to address these symptoms promptly to avoid further complications. Additionally, some owners encounter a "Exhaust Fluid Quality Poor" message, which could be linked to the SCR system or NOx sensors, potentially caused by crystal build-up affecting sensor performance and triggering limp mode. If issues with the DEF system arise, resetting it may help restore proper functionality. For persistent problems, further diagnostics, including checking fault codes and inspecting the SCR system, may be necessary. If unresolved, seeking professional assistance from a qualified mechanic is advisable to effectively address the check engine light and exhaust fluid quality concerns.