Cummins ISB6.7 CM2350 (2013-17) Fault Code: 5248 PID: SPN: 1623 FMI: 13 Tachograph Output Shaft Speed – Out of Calibration – The received datalink message was not valid.

Cummins ISB6.7 CM2350 (2013-17) Fault Code: 5248 PID: SPN: 1623 FMI: 13 Tachograph Output Shaft Speed – Out of Calibration – The received datalink message was not valid.

Circuit Description
Normally, switches, accelerators, and other components are connected to the engine control module (ECM) directly through individual wires. Multiplexing allows those same components to be hard wired to an original equipment manufacturer (OEM) vehicle electronic control unit (VECU) or transmission electronic control unit (ECU) in the cab. Then component values and states from components such as sensors, accelerators, and switches can be transmitted from the OEM VECU to the Cummins? ECM over the SAE J1939 data link.

Messages sent from OEM VECUs or transmission ECUs are received by the Cummins? ECM and used for controlling the engine. The Cummins? ECM and OEM VECU(s) must be configured properly, so that proper operation of the multiplexed components will occur.

Component Location
The SAE J1939 data link wiring and the SAE J1939 devices vary by OEM options.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes
The OEM VECU determined that there was a malfunction of the tachograph output shaft speed sensor.

Action Taken When the Fault Code is Active
1)The ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and fails.
2)The ECM will illuminate the Malfunction Indicator Lamp (MIL) after an extended period of time with the fault code active.

Conditions for Clearing the Fault Code
1)To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2)The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3)The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
4)For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after four consecutive trips where the diagnostic runs and passes.

The Reset All Faults command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk
The J1939 multiplexing controller has indicated a malfunction of the tachograph output shaft speed sensor.