Accu-Chek Combo Error codes E7: ELECTTRONIC ERROR An electronic error has been discovered in the pump during a routine automatic system check. Change the battery. If the message still occurs, contact Accu-Chek Customer Care for advice. E6: MECHANICAL ERROR E6: MECHANICAL ERROR An error in the mechanical system of the… Error E4: OCCLUSION E-4 Occlusion detection View all error messages