DTC Check: Notes

NOTE: The MIL is turned on when the ECM and/or TCM detect malfunction(s). Each ECU stores diagnostic information as the diagnostic trouble code (DTC) in its memory and outputs the DTC to the scan tool. Therefore, check both of the ECUs for any DTC with the scan tool because the DTC stored in ECU and TCM is not read and displayed at a time. However, each of the ECUs needs not to be checked with the generic scan tool because the DTC stored in ECM and TCM is read and displayed at a time.

Automatic transmission DTC can be checked using any one of the following 2 methods.