The ECM communicate over the CAN are the EMS(Engine Management System), TCS(Traction Control System) TCM(Transmission Control Moudle). The TCM monitors various information such as vehicle speed , gear position and engine torque during upshift, it request the ECM to retard ignition timing to lower torque. This produces small change in torque during upshift, hence smooth shift and increase in shift feeling. In case of the TCM failure, the engine symptoms will occur a corrupted torque reduction signal information, a shift shock, a increasing engine rpm abruptly.

If the error between the ECM and the TCM is detected during two back-to-back trips and this code will be set.