CM850 Electronic Control System – FAULT CODE 498

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Overview

ISB — Oil Level Sensor Circuit SMALL | MEDIUM | LARGE

ISL and ISLe — Oil Level Sensor Circuit SMALL | MEDIUM | LARGE

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 the engine key-on, if the oil level sensor detects a critical low oil level, then the amber CHECK ENGINE light will blink for 30 seconds and a fault code will be logged. If an operator observes a blinking amber CHECK ENGINE light 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 oil dipstick port. Refer to Procedure 100-002 for a detailed component location view.

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 oil level sensor has detected an internal short or open circuit.

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.

Shop Talk

Possible causes of this fault code include:

• Open or short circuit internally to the oil level sensor
• A malfunctioning oil level sensor.

Refer to Troubleshooting Fault Code t05-498