Cummins ISB4.5 CM2150 Fault Code: 252 PID: SPN: 98 FMI: 2 Engine Oil Level – Data Erratic, Intermittent, or Incorrect.

Circuit Description
The oil level sensor will monitor the oil fluid level in the oil pan at key ON. The oil level sensor will not monitor the oil level after the engine is started or when the engine speed is greater than 0 rpm. During engine key ON, if the oil level sensor detects a critical low oil level, then the amber CHECK ENGINE lamp will blink for 30 seconds and a fault code will be logged. If an operator observes a blinking amber CHECK ENGINE lamp at key ON, the operator must check the engine oil level with the manual dipstick.

The oil level sensor provides the electronic control module (ECM) with a pulse width modulated (PWM) signal. Within this signal, the oil level sensor transmits the engine oil level reading, oil temperature, and fault code information from the oil level sensor.

Component Location
The oil level sensor is located on the left side of the engine on the front part of the dipstick port.

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

Conditions for Setting the Fault Codes
A valid PWM message is not received from the oil level sensor within the required time limits at initial key ON.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
-The oil level sensor operation will be disabled.

Conditions for Clearing the Fault Code
The ECM will turn off the amber CHECK ENGINE light and enable oil level sensor operation immediately after a valid PWM signal is received from the oil level sensor.

Possible Causes
-The oil level sensor is not receiving power from the ECM. This can be caused by an open circuit in the power supply or low voltage supplied by the primary engine ECM
-Open return circuit on the oil level sensor circuit between the engine ECM and the oil level sensor
-Open or short circuit on the oil level sensor signal circuit between the ECM and oil level sensor
-A damaged oil level sensor.