Instrument Pack 1 Instrument pack 2 Transmission status display 3 Message centre 4 Malfunction Indicator Lamp (MIL) The instrument pack is connected to the EAT ECU via the CAN. Transmission status is transmitted by the EAT ECU and displayed to the driver on one of two displays in the instrument pack + INSTRUMENTS, DESCRIPTION AND OPERATION, Description. Malfunction Indicator Lamp (MIL) The MIL is located in the lower left hand corner of the instrument pack, below the fuel gauge. Transmission related faults which may affect the vehicle emissions output will illuminate the MIL. The MIL is illuminated by the ECM on receipt of a relevant fault message from the EAT ECU on the CAN. The nature of the fault can be diagnosed using TestBook which reads fault codes stored in the ECU memory.