DTC C1646-83: CAN Signal Error TCU: General Description

The Hydraulic Electronic Control Unit (HECU) sends requirement data, such as torque reduction, the number of fuel cut cylinders, and the ESP control request, to the Engine Control Module (ECM)/Powertrain Control Module (PCM) through CAN bus line. The ECM/PCM performs the fuel cut function according to a request signal from the HECU and then retards an ignition timing. The Transmission Control Module (TCM)/Powertrain Control Module (PCM) maintains current gear position during the ESP control period in order not to increase power which causes a kickdown shift.