This Preliminary Information communication advises the technician that vehicles with engine Regular Production Option Code LGH or LML may have an Exhaust Fluid Quality Poor message displayed on the Driver Information Center. Technician will need to complete the current Service Information diagnostic for any current Diagnostic Trouble Codes or symptoms found. If an Exhaust Fluid Quality Poor message is displayed with a specific Diagnostic Trouble Code, use that specific Service Information diagnostic, and repair the vehicle as necessary. If the dealer has found an Exhaust Fluid Quality Poor message with no Diagnostic Trouble Code, diagnose the condition using the current Service Information diagnosis for Diagnostic Trouble Code P20EE / P207F (P2BAD for 2012 and newer model years). After making repairs use the Service Information Document titled "Reductant Fluid Quality Test (With or without Diagnostic Trouble Codes)" to evaluate and clear the Exhaust Fluid Quality Poor Driver Information Center message.