The CIS-E Motronic ignition system is also TCI-h with knock control. As in Digifant, all ignition functions including the knock sensor system are combined with fuel injection control in the single Motronic control unit. Ignition timing is based on engine load, engine speed, ignition quality (knock), and coolant temperature. Two knock sensors are used in CIS-E Motronic, along with a knock control reference sensor. The reference sensor allows the control unit to determine which pair of cylinders is knocking. CIS-E Motronic does not have an ignition control unit. Instead, the Hall sender signal is monitored by the Motronic control unit. The control unit then sends a signal to the ignition coil power stage, which switches power to the coil.