Cummins ISB4.5 CM2150 Fault Code: 784 PID: SID 145 SPN: 1590 FMI: 2 Adaptive Cruise Control Mode – Data Erratic, Intermittent, or Incorrect.

Circuit Description
The adaptive cruise control unit communicates with the engine control module (ECM) sending and receiving vehicle speed control messages through the SAE J1939 data link.

Component Location
The location of the adaptive cruise control unit will vary by original equipment manufacturer (OEM). Refer to the OEM service manual for specific location.

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

Conditions for Setting the Fault Codes
The ECM does not receive a valid J1939 message from the adaptive cruise control module for more than 1 second.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
-The adaptive cruise control will not operate.

Conditions for Clearing the Fault Code
The ECM will turn off the amber CHECK ENGINE light immediately after the diagnostic runs and passes.

Shop Talk
If Adaptive Cruise Recovery is enabled, the driver can toggle the cruise enable switch from the OFF position to the ON position two times to get regular cruise control to operate, and Fault Code 784 will go inactive. At the next key cycle, if the Heartbeat message is still not present, Fault Code 784 will go active.