Automotive Diagnostics — Control DTC Setting

The control DTC Setting service is used when the client/Tester needs to stop or resume the server/ECU updating the DTC when a fault occurs. This would be very helpful when the client knows the issue in the vehicle but is trying to root cause by doing some additional experiments.

Important points about Control DTC setting service

• When the client requests the server to switch “OFF” updating the server communication, the server freezes the current values of DTC and suspends any update of the DTC values.
• The server then updates the DTC values again when the client requests the server to switch “ON” the DTC update. The two points would be clear as you read further.
• If the client requests the service to be switched “OFF” when the DTC setting of the server or ECU is already in “OFF” mode, the server/ECU responds with a positive response ignoring the request
• If there is a Clear Diagnostic information service (0x14) requested by the user when the control DTC setting is in “OFF” state, the server may still clear the DTC information.
• Any of the system failsafe functionality would not be changed by the Control DTC setting service. Instead, reporting of the DTCs would only be modified.

Sub-functions supported by control DTC setting service are