Cummins ISX12 CM2250 (2010-12) Fault Code: 196 (2 Wire) PID: 2558 SPN: 111 FMI: 4 Coolant Level Sensor 1 Circuit- Voltage Below Normal or Shorted to Low Source

Circuit Description
The engine control module (ECM) provides a 5 volt supply to the engine coolant level sensor using a common sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The engine coolant level sensor provides a signal to the ECM on the engine coolant level sensor signal circuit. This sensor signal voltage changes based on the coolant level in the expansion tank.

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 location.

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 ECM detects that the coolant level signal voltage is less than a calibratible value 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.
No engine protection will be available for low coolant level.
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 and the fault code will go inactive immediately after the diagnostic runs and passes.
This fault code can also be cleared with INSITE? electronic service tool.

Shop Talk
Verify the ECM calibration is correct. Check the calibration revision history found on QuickServe? Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM.

Possible causes of this fault code include:

Open signal circuit in the engine harness, connectors, or sensor
Signal circuit shorted to ground in the harness, sensor or connectors
Damaged sensor.
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and data link communication issues with Aftertreatment Components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing or intermittent connections.

Possible Cause:
1) ECM failure
2) OEM harness