Cummins ISB4.5 CM2150 Fault Code: 197 PID: 2560 SPN: 111 FMI: 1 Coolant Level – Data Valid But Below Normal Operating Range – Moderately Severe Level.

Circuit Description
The coolant level sensor is a switch and is used to measure the level of the engine coolant in the radiator top tank. The coolant level sensor is immersed in the coolant and returns a different signal voltage when immersed in coolant versus being out of coolant. The electronic control module (ECM) supplies 5 volts to the coolant level signal circuit. The resistance of the engine coolant level sensor changes, based on the coolant level. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the level of the engine coolant.

Component Location
The engine coolant level sensor is typically located in the radiator top tank or surge tank. Refer to the original equipment manufacturer (OEM) service manual for the location.

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

Conditions for Setting the Fault Codes
The ECM detects that the coolant level is below the normal operating limits.

Action Taken When the Fault Code is Active
-The ECM illuminated the amber CHECK ENGINE light and/or malfunction indicator lamp (MIL) after 20 seconds when low engine coolant level has been detected.

Conditions for Clearing the Fault Code
-To validate the repair, start the engine and let it idle for 1 minute.
-The ECM will turn off the amber CHECK ENGINE light immediately after 20 seconds of detecting the correct engine coolant level.
-The ECM will turn off the MIL after three consecutive ignition cycles that the diagnostic runs and passes.
-This fault code and MIL can also be cleared with INSITE™ electronic service tool.

Shop Talk
This fault code becomes active when the coolant level inside the radiator top tank or surge tank drops below the sensor level. Fill the top tank with coolant.